From: Junio C Hamano <gitster@pobox.com>
Date: Thu, 14 Mar 2024 21:05:23 +0000 (-0700)
Subject: Merge branch 'ps/reftable-iteration-perf-part2'
X-Git-Tag: v2.45.0-rc0~116
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=448a74e1515ca63bc0877a0461624d7beb1bec2e;hp=43f70eaea0e3fa9d98c895e9341674a67262b657;p=thirdparty%2Fgit.git

Merge branch 'ps/reftable-iteration-perf-part2'

The code to iterate over refs with the reftable backend has seen
some optimization.

* ps/reftable-iteration-perf-part2:
  refs/reftable: precompute prefix length
  reftable: allow inlining of a few functions
  reftable/record: decode keys in place
  reftable/record: reuse refname when copying
  reftable/record: reuse refname when decoding
  reftable/merged: avoid duplicate pqueue emptiness check
  reftable/merged: circumvent pqueue with single subiter
  reftable/merged: handle subiter cleanup on close only
  reftable/merged: remove unnecessary null check for subiters
  reftable/merged: make subiters own their records
  reftable/merged: advance subiter on subsequent iteration
  reftable/merged: make `merged_iter` structure private
  reftable/pq: use `size_t` to track iterator index
---

diff --git a/Documentation/CodingGuidelines b/Documentation/CodingGuidelines
index 578587a471..32e69f798e 100644
--- a/Documentation/CodingGuidelines
+++ b/Documentation/CodingGuidelines
@@ -446,12 +446,41 @@ For C programs:
    detail.
 
  - The first #include in C files, except in platform specific compat/
-   implementations and sha1dc/, must be either "git-compat-util.h" or
-   one of the approved headers that includes it first for you.  (The
-   approved headers currently include "builtin.h",
-   "t/helper/test-tool.h", "xdiff/xinclude.h", or
-   "reftable/system.h".)  You do not have to include more than one of
-   these.
+   implementations and sha1dc/, must be <git-compat-util.h>.  This
+   header file insulates other header files and source files from
+   platform differences, like which system header files must be
+   included in what order, and what C preprocessor feature macros must
+   be defined to trigger certain features we expect out of the system.
+   A collorary to this is that C files should not directly include
+   system header files themselves.
+
+   There are some exceptions, because certain group of files that
+   implement an API all have to include the same header file that
+   defines the API and it is convenient to include <git-compat-util.h>
+   there.  Namely:
+
+   - the implementation of the built-in commands in the "builtin/"
+     directory that include "builtin.h" for the cmd_foo() prototype
+     definition,
+
+   - the test helper programs in the "t/helper/" directory that include
+     "t/helper/test-tool.h" for the cmd__foo() prototype definition,
+
+   - the xdiff implementation in the "xdiff/" directory that includes
+     "xdiff/xinclude.h" for the xdiff machinery internals,
+
+   - the unit test programs in "t/unit-tests/" directory that include
+     "t/unit-tests/test-lib.h" that gives them the unit-tests
+     framework, and
+
+   - the source files that implement reftable in the "reftable/"
+     directory that include "reftable/system.h" for the reftable
+     internals,
+
+   are allowed to assume that they do not have to include
+   <git-compat-util.h> themselves, as it is included as the first
+   '#include' in these header files.  These headers must be the first
+   header file to be "#include"d in them, though.
 
  - A C file must directly include the header files that declare the
    functions and the types it uses, except for the functions and types
@@ -666,6 +695,11 @@ Writing Documentation:
    <new-branch-name>
    --template=<template-directory>
 
+ When a placeholder is cited in text paragraph, it is enclosed in angle
+ brackets to remind the reader the reference in the synopsis section.
+ For better visibility, the placeholder is typeset in italics:
+   The _<file>_ to be added.
+
  Possibility of multiple occurrences is indicated by three dots:
    <file>...
    (One or more of <file>.)
@@ -751,6 +785,8 @@ Writing Documentation:
    Incorrect:
       `\--pretty=oneline`
 
+A placeholder is not enclosed in backticks, as it is not a literal.
+
  If some place in the documentation needs to typeset a command usage
  example with inline substitutions, it is fine to use +monospaced and
  inline substituted text+ instead of `monospaced literal text`, and with
diff --git a/Documentation/RelNotes/2.45.0.txt b/Documentation/RelNotes/2.45.0.txt
index 4f5a01c611..2e75932539 100644
--- a/Documentation/RelNotes/2.45.0.txt
+++ b/Documentation/RelNotes/2.45.0.txt
@@ -12,6 +12,28 @@ UI, Workflows & Features
  * "git checkout -p" and friends learned that that "@" is a synonym
    for "HEAD".
 
+ * Variants of vimdiff learned to honor mergetool.<variant>.layout
+   settings.
+
+ * "git reflog" learned a "list" subcommand that enumerates known reflogs.
+
+ * When a merge conflicted at a submodule, merge-ort backend used to
+   unconditionally give a lengthy message to suggest how to resolve
+   it.  Now the message can be squelched as an advice message.
+
+ * "git for-each-ref" learned "--include-root-refs" option to show
+   even the stuff outside the 'refs/' hierarchy.
+
+ * "git rev-list --missing=print" has learned to optionally take
+   "--allow-missing-tips", which allows the objects at the starting
+   points to be missing.
+
+ * "git merge-tree" has learned that the three trees involved in the
+   3-way merge only need to be trees, not necessarily commits.
+
+ * "git log --merge" learned to pay attention to CHERRY_PICK_HEAD and
+   other kinds of *_HEAD pseudorefs.
+
 
 Performance, Internal Implementation, Development Support etc.
 
@@ -21,6 +43,17 @@ Performance, Internal Implementation, Development Support etc.
  * More tests that are marked as "ref-files only" have been updated to
    improve test coverage of reftable backend.
 
+ * Some parts of command line completion script (in contrib/) have
+   been micro-optimized.
+
+ * The way placeholders are to be marked-up in documentation have been
+   specified; use "_<placeholder>_" to typeset the word inside a pair
+   of <angle-brakets> emphasized.
+
+ * "git --no-lazy-fetch cmd" allows to run "cmd" while disabling lazy
+   fetching of objects from the promisor remote, which may be handy
+   for debugging.
+
 
 Fixes since v2.44
 -----------------
@@ -36,5 +69,80 @@ Fixes since v2.44
    it would lead to nonsense behaviour including division by zero.
    (merge 76fb807faa kh/column-reject-negative-padding later to maint).
 
+ * "git am --help" now tells readers what actions are available in
+   "git am --whitespace=<action>", in addition to saying that the
+   option is passed through to the underlying "git apply".
+   (merge a171dac734 jc/am-whitespace-doc later to maint).
+
+ * "git tag --column" failed to check the exit status of its "git
+   column" invocation, which has been corrected.
+   (merge 92e66478fc rj/tag-column-fix later to maint).
+
+ * Credential helper based on libsecret (in contrib/) has been updated
+   to handle an empty password correctly.
+   (merge 8f1f2023b7 mh/libsecret-empty-password-fix later to maint).
+
+ * "git difftool --dir-diff" learned to honor the "--trust-exit-code"
+   option; it used to always exit with 0 and signalled success.
+   (merge eb84c8b6ce ps/difftool-dir-diff-exit-code later to maint).
+
+ * The code incorrectly attempted to use textconv cache when asked,
+   even when we are not running in a repository, which has been
+   corrected.
+   (merge affe355fe7 jk/textconv-cache-outside-repo-fix later to maint).
+
+ * Remove an empty file that shouldn't have been added in the first
+   place.
+   (merge 4f66942215 js/remove-cruft-files later to maint).
+
+ * The logic to access reflog entries by date and number had ugly
+   corner cases at the boundaries, which have been cleaned up.
+   (merge 5edd126720 jk/reflog-special-cases-fix later to maint).
+
+ * An error message from "git upload-pack", which responds to "git
+   fetch" requests, had a trialing NUL in it, which has been
+   corrected.
+   (merge 3f4c7a0805 sg/upload-pack-error-message-fix later to maint).
+
+ * Clarify wording in the CodingGuidelines that requires <git-compat-util.h>
+   to be the first header file.
+   (merge 4e89f0e07c jc/doc-compat-util later to maint).
+
+ * "git commit -v --cleanup=scissors" used to add the scissors line
+   twice in the log message buffer, which has been corrected.
+   (merge e90cc075cc jt/commit-redundant-scissors-fix later to maint).
+
+ * A custom remote helper no longer cannot access the newly created
+   repository during "git clone", which is a regression in Git 2.44.
+   This has been corrected.
+   (merge 199f44cb2e ps/remote-helper-repo-initialization-fix later to maint).
+
+ * Various parts of upload-pack has been updated to bound the resource
+   consumption relative to the size of the repository to protect from
+   abusive clients.
+   (merge 6cd05e768b jk/upload-pack-bounded-resources later to maint).
+
+ * The upload-pack program, when talking over v2, accepted the
+   packfile-uris protocol extension from the client, even if it did
+   not advertise the capability, which has been corrected.
+   (merge a922bfa3b5 jk/upload-pack-v2-capability-cleanup later to maint).
+
+ * Make sure failure return from merge_bases_many() is properly caught.
+   (merge 25fd20eb44 js/merge-base-with-missing-commit later to maint).
+
  * Other code cleanup, docfix, build fix, etc.
    (merge f0e578c69c rs/use-xstrncmpz later to maint).
+   (merge 83e6eb7d7a ba/credential-test-clean-fix later to maint).
+   (merge 64562d784d jb/doc-interactive-singlekey-do-not-need-perl later to maint).
+   (merge c431a235e2 cp/t9146-use-test-path-helpers later to maint).
+   (merge 82d75402d5 ds/doc-send-email-capitalization later to maint).
+   (merge 41bff66e35 jc/doc-add-placeholder-fix later to maint).
+   (merge 6835f0efe9 jw/remote-doc-typofix later to maint).
+   (merge 244001aa20 hs/rebase-not-in-progress later to maint).
+   (merge 2ca6c07db2 jc/no-include-of-compat-util-from-headers later to maint).
+   (merge 87bd7fbb9c rs/fetch-simplify-with-starts-with later to maint).
+   (merge f39addd0d9 rs/name-rev-with-mempool later to maint).
+   (merge 9a97b43e03 rs/submodule-prefix-simplify later to maint).
+   (merge 40b8076462 ak/rebase-autosquash later to maint).
+   (merge 3223204456 eg/add-uflags later to maint).
+   (merge 5f78d52dce es/config-doc-sort-sections later to maint).
diff --git a/Documentation/config.txt b/Documentation/config.txt
index e3a74dd1c1..782c2bab90 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -369,20 +369,18 @@ inventing new variables for use in your own tool, make sure their
 names do not conflict with those that are used by Git itself and
 other popular tools, and describe them in your documentation.
 
-include::config/advice.txt[]
-
-include::config/attr.txt[]
-
-include::config/core.txt[]
-
 include::config/add.txt[]
 
+include::config/advice.txt[]
+
 include::config/alias.txt[]
 
 include::config/am.txt[]
 
 include::config/apply.txt[]
 
+include::config/attr.txt[]
+
 include::config/blame.txt[]
 
 include::config/branch.txt[]
@@ -405,10 +403,12 @@ include::config/commit.txt[]
 
 include::config/commitgraph.txt[]
 
-include::config/credential.txt[]
-
 include::config/completion.txt[]
 
+include::config/core.txt[]
+
+include::config/credential.txt[]
+
 include::config/diff.txt[]
 
 include::config/difftool.txt[]
@@ -421,10 +421,10 @@ include::config/feature.txt[]
 
 include::config/fetch.txt[]
 
-include::config/format.txt[]
-
 include::config/filter.txt[]
 
+include::config/format.txt[]
+
 include::config/fsck.txt[]
 
 include::config/fsmonitor--daemon.txt[]
@@ -435,10 +435,10 @@ include::config/gitcvs.txt[]
 
 include::config/gitweb.txt[]
 
-include::config/grep.txt[]
-
 include::config/gpg.txt[]
 
+include::config/grep.txt[]
+
 include::config/gui.txt[]
 
 include::config/guitool.txt[]
@@ -519,10 +519,10 @@ include::config/splitindex.txt[]
 
 include::config/ssh.txt[]
 
-include::config/status.txt[]
-
 include::config/stash.txt[]
 
+include::config/status.txt[]
+
 include::config/submodule.txt[]
 
 include::config/tag.txt[]
diff --git a/Documentation/config/advice.txt b/Documentation/config/advice.txt
index c7ea70f2e2..dde8e7840e 100644
--- a/Documentation/config/advice.txt
+++ b/Documentation/config/advice.txt
@@ -129,6 +129,9 @@ advice.*::
 	submoduleAlternateErrorStrategyDie::
 		Advice shown when a submodule.alternateErrorStrategy option
 		configured to "die" causes a fatal error.
+	submoduleMergeConflict::
+		Advice shown when a non-trivial submodule merge conflict is
+		encountered.
 	submodulesNotUpdated::
 		Advice shown when a user runs a submodule command that fails
 		because `git submodule update --init` was not run.
diff --git a/Documentation/config/clean.txt b/Documentation/config/clean.txt
index f05b9403b5..c0188ead4e 100644
--- a/Documentation/config/clean.txt
+++ b/Documentation/config/clean.txt
@@ -1,3 +1,3 @@
 clean.requireForce::
-	A boolean to make git-clean do nothing unless given -f,
-	-i, or -n.  Defaults to true.
+	A boolean to make git-clean refuse to delete files unless -f
+	is given. Defaults to true.
diff --git a/Documentation/config/diff.txt b/Documentation/config/diff.txt
index bd5ae0c337..6c7e09a1ef 100644
--- a/Documentation/config/diff.txt
+++ b/Documentation/config/diff.txt
@@ -223,5 +223,5 @@ diff.colorMoved::
 
 diff.colorMovedWS::
 	When moved lines are colored using e.g. the `diff.colorMoved` setting,
-	this option controls the `<mode>` how spaces are treated
-	for details of valid modes see '--color-moved-ws' in linkgit:git-diff[1].
+	this option controls the `<mode>` how spaces are treated.
+	For details of valid modes see '--color-moved-ws' in linkgit:git-diff[1].
diff --git a/Documentation/config/interactive.txt b/Documentation/config/interactive.txt
index a2d3c7ec44..5cc26555f1 100644
--- a/Documentation/config/interactive.txt
+++ b/Documentation/config/interactive.txt
@@ -4,9 +4,7 @@ interactive.singleKey::
 	Currently this is used by the `--patch` mode of
 	linkgit:git-add[1], linkgit:git-checkout[1],
 	linkgit:git-restore[1], linkgit:git-commit[1],
-	linkgit:git-reset[1], and linkgit:git-stash[1]. Note that this
-	setting is silently ignored if portable keystroke input
-	is not available; requires the Perl module Term::ReadKey.
+	linkgit:git-reset[1], and linkgit:git-stash[1].
 
 interactive.diffFilter::
 	When an interactive command (such as `git add --patch`) shows
diff --git a/Documentation/config/mergetool.txt b/Documentation/config/mergetool.txt
index 294f61efd1..00bf665aa0 100644
--- a/Documentation/config/mergetool.txt
+++ b/Documentation/config/mergetool.txt
@@ -45,14 +45,21 @@ mergetool.meld.useAutoMerge::
 	value of `false` avoids using `--auto-merge` altogether, and is the
 	default value.
 
-mergetool.vimdiff.layout::
-	The vimdiff backend uses this variable to control how its split
-	windows appear. Applies even if you are using Neovim (`nvim`) or
-	gVim (`gvim`) as the merge tool. See BACKEND SPECIFIC HINTS section
+mergetool.<vimdiff variant>.layout::
+	Configure the split window layout for vimdiff's `<variant>`, which is any of `vimdiff`,
+	`nvimdiff`, `gvimdiff`.
+	Upon launching `git mergetool` with `--tool=<variant>` (or without `--tool`
+	if `merge.tool` is configured as `<variant>`), Git will consult
+	`mergetool.<variant>.layout` to determine the tool's layout. If the
+	variant-specific configuration is not available, `vimdiff`'s is used as
+	fallback.  If that too is not available, a default layout with 4 windows
+	will be used.  To configure the layout, see the `BACKEND SPECIFIC HINTS`
+ifdef::git-mergetool[]
+	section.
+endif::[]
 ifndef::git-mergetool[]
-	in linkgit:git-mergetool[1].
+	section in linkgit:git-mergetool[1].
 endif::[]
-	for details.
 
 mergetool.hideResolved::
 	During a merge, Git will automatically resolve as many conflicts as
diff --git a/Documentation/config/pack.txt b/Documentation/config/pack.txt
index 9c630863e6..da527377fa 100644
--- a/Documentation/config/pack.txt
+++ b/Documentation/config/pack.txt
@@ -34,11 +34,10 @@ pack.allowPackReuse::
 	reachability bitmap is available, pack-objects will try to send
 	parts of all packs in the MIDX.
 +
-	If only a single pack bitmap is available, and
-	`pack.allowPackReuse` is set to "multi", reuse parts of just the
-	bitmapped packfile. This can reduce memory and CPU usage to
-	serve fetches, but might result in sending a slightly larger
-	pack. Defaults to true.
+If only a single pack bitmap is available, and `pack.allowPackReuse`
+is set to "multi", reuse parts of just the bitmapped packfile. This
+can reduce memory and CPU usage to serve fetches, but might result in
+sending a slightly larger pack. Defaults to true.
 
 pack.island::
 	An extended regular expression configuring a set of delta
diff --git a/Documentation/config/sendemail.txt b/Documentation/config/sendemail.txt
index 7fc770ee9e..6a869d67eb 100644
--- a/Documentation/config/sendemail.txt
+++ b/Documentation/config/sendemail.txt
@@ -8,7 +8,7 @@ sendemail.smtpEncryption::
 	See linkgit:git-send-email[1] for description.  Note that this
 	setting is not subject to the 'identity' mechanism.
 
-sendemail.smtpsslcertpath::
+sendemail.smtpSSLCertPath::
 	Path to ca-certificates (either a directory or a single file).
 	Set it to an empty string to disable certificate verification.
 
@@ -62,12 +62,12 @@ sendemail.chainReplyTo::
 sendemail.envelopeSender::
 sendemail.from::
 sendemail.headerCmd::
-sendemail.signedoffbycc::
+sendemail.signedOffByCc::
 sendemail.smtpPass::
-sendemail.suppresscc::
+sendemail.suppressCc::
 sendemail.suppressFrom::
 sendemail.to::
-sendemail.tocmd::
+sendemail.toCmd::
 sendemail.smtpDomain::
 sendemail.smtpServer::
 sendemail.smtpServerPort::
@@ -81,8 +81,8 @@ sendemail.xmailer::
 	linkgit:git-send-email[1] command-line options. See its
 	documentation for details.
 
-sendemail.signedoffcc (deprecated)::
-	Deprecated alias for `sendemail.signedoffbycc`.
+sendemail.signedOffCc (deprecated)::
+	Deprecated alias for `sendemail.signedOffByCc`.
 
 sendemail.smtpBatchSize::
 	Number of messages to be sent per connection, after that a relogin
diff --git a/Documentation/config/transfer.txt b/Documentation/config/transfer.txt
index a9cbdb88a1..f1ce50f4a6 100644
--- a/Documentation/config/transfer.txt
+++ b/Documentation/config/transfer.txt
@@ -121,3 +121,7 @@ transfer.bundleURI::
 	information from the remote server (if advertised) and download
 	bundles before continuing the clone through the Git protocol.
 	Defaults to `false`.
+
+transfer.advertiseObjectInfo::
+	When `true`, the `object-info` capability is advertised by
+	servers. Defaults to false.
diff --git a/Documentation/git-add.txt b/Documentation/git-add.txt
index 3d2e670716..14a371fff3 100644
--- a/Documentation/git-add.txt
+++ b/Documentation/git-add.txt
@@ -63,7 +63,7 @@ OPTIONS
 	to ignore removed files; use `--no-all` option if you want
 	to add modified or new files but ignore removed ones.
 +
-For more details about the <pathspec> syntax, see the 'pathspec' entry
+For more details about the _<pathspec>_ syntax, see the 'pathspec' entry
 in linkgit:gitglossary[7].
 
 -n::
@@ -119,10 +119,10 @@ apply to the index. See EDITING PATCHES below.
 -u::
 --update::
 	Update the index just where it already has an entry matching
-	<pathspec>.  This removes as well as modifies index entries to
+	_<pathspec>_.  This removes as well as modifies index entries to
 	match the working tree, but adds no new files.
 +
-If no <pathspec> is given when `-u` option is used, all
+If no _<pathspec>_ is given when `-u` option is used, all
 tracked files in the entire working tree are updated (old versions
 of Git used to limit the update to the current directory and its
 subdirectories).
@@ -131,11 +131,11 @@ subdirectories).
 --all::
 --no-ignore-removal::
 	Update the index not only where the working tree has a file
-	matching <pathspec> but also where the index already has an
+	matching _<pathspec>_ but also where the index already has an
 	entry. This adds, modifies, and removes index entries to
 	match the working tree.
 +
-If no <pathspec> is given when `-A` option is used, all
+If no _<pathspec>_ is given when `-A` option is used, all
 files in the entire working tree are updated (old versions
 of Git used to limit the update to the current directory and its
 subdirectories).
@@ -145,11 +145,11 @@ subdirectories).
 	Update the index by adding new files that are unknown to the
 	index and files modified in the working tree, but ignore
 	files that have been removed from the working tree.  This
-	option is a no-op when no <pathspec> is used.
+	option is a no-op when no _<pathspec>_ is used.
 +
 This option is primarily to help users who are used to older
-versions of Git, whose "git add <pathspec>..." was a synonym
-for "git add --no-all <pathspec>...", i.e. ignored removed files.
+versions of Git, whose "git add _<pathspec>_..." was a synonym
+for "git add --no-all _<pathspec>_...", i.e. ignored removed files.
 
 -N::
 --intent-to-add::
@@ -198,8 +198,8 @@ for "git add --no-all <pathspec>...", i.e. ignored removed files.
 	unchanged.
 
 --pathspec-from-file=<file>::
-	Pathspec is passed in `<file>` instead of commandline args. If
-	`<file>` is exactly `-` then standard input is used. Pathspec
+	Pathspec is passed in _<file>_ instead of commandline args. If
+	_<file>_ is exactly `-` then standard input is used. Pathspec
 	elements are separated by LF or CR/LF. Pathspec elements can be
 	quoted as explained for the configuration variable `core.quotePath`
 	(see linkgit:git-config[1]). See also `--pathspec-file-nul` and
diff --git a/Documentation/git-am.txt b/Documentation/git-am.txt
index e080458d6c..463a3c6600 100644
--- a/Documentation/git-am.txt
+++ b/Documentation/git-am.txt
@@ -128,6 +128,9 @@ include::rerere-options.txt[]
 	These flags are passed to the 'git apply' (see linkgit:git-apply[1])
 	program that applies
 	the patch.
++
+Valid <action> for the `--whitespace` option are:
+`nowarn`, `warn`, `fix`, `error`, and `error-all`.
 
 --patch-format::
 	By default the command will try to detect the patch format
diff --git a/Documentation/git-clean.txt b/Documentation/git-clean.txt
index 69331e3f05..fd17165416 100644
--- a/Documentation/git-clean.txt
+++ b/Documentation/git-clean.txt
@@ -37,7 +37,7 @@ OPTIONS
 --force::
 	If the Git configuration variable clean.requireForce is not set
 	to false, 'git clean' will refuse to delete files or directories
-	unless given -f or -i.  Git will refuse to modify untracked
+	unless given -f.  Git will refuse to modify untracked
 	nested git repositories (directories with a .git subdirectory)
 	unless a second -f is given.
 
@@ -45,10 +45,14 @@ OPTIONS
 --interactive::
 	Show what would be done and clean files interactively. See
 	``Interactive mode'' for details.
+	Configuration variable `clean.requireForce` is ignored, as
+	this mode gives its own safety protection by going interactive.
 
 -n::
 --dry-run::
 	Don't actually remove anything, just show what would be done.
+	Configuration variable `clean.requireForce` is ignored, as
+	nothing will be deleted anyway.
 
 -q::
 --quiet::
diff --git a/Documentation/git-clone.txt b/Documentation/git-clone.txt
index 6e43eb9c20..0c07720c6f 100644
--- a/Documentation/git-clone.txt
+++ b/Documentation/git-clone.txt
@@ -311,7 +311,7 @@ or `--mirror` is given)
 	The result is Git repository can be separated from working
 	tree.
 
---ref-format=<ref-format::
+--ref-format=<ref-format>::
 
 Specify the given ref storage format for the repository. The valid values are:
 +
diff --git a/Documentation/git-difftool.txt b/Documentation/git-difftool.txt
index c05f97aca9..a616f8b2e6 100644
--- a/Documentation/git-difftool.txt
+++ b/Documentation/git-difftool.txt
@@ -105,7 +105,6 @@ instead.  `--no-symlinks` is the default on Windows.
 	`merge.tool` until a tool is found.
 
 --[no-]trust-exit-code::
-	'git-difftool' invokes a diff tool individually on each file.
 	Errors reported by the diff tool are ignored by default.
 	Use `--trust-exit-code` to make 'git-difftool' exit when an
 	invoked diff tool returns a non-zero exit code.
diff --git a/Documentation/git-fast-export.txt b/Documentation/git-fast-export.txt
index 4643ddbe68..752e4b9b01 100644
--- a/Documentation/git-fast-export.txt
+++ b/Documentation/git-fast-export.txt
@@ -48,7 +48,7 @@ When asking to 'abort' (which is the default), this program will die
 when encountering such a tag.  With 'drop' it will omit such tags from
 the output.  With 'rewrite', if the tagged object is a commit, it will
 rewrite the tag to tag an ancestor commit (via parent rewriting; see
-linkgit:git-rev-list[1])
+linkgit:git-rev-list[1]).
 
 -M::
 -C::
diff --git a/Documentation/git-for-each-ref.txt b/Documentation/git-for-each-ref.txt
index 3a9ad91b7a..c1dd12b93c 100644
--- a/Documentation/git-for-each-ref.txt
+++ b/Documentation/git-for-each-ref.txt
@@ -10,7 +10,7 @@ SYNOPSIS
 [verse]
 'git for-each-ref' [--count=<count>] [--shell|--perl|--python|--tcl]
 		   [(--sort=<key>)...] [--format=<format>]
-		   [ --stdin | <pattern>... ]
+		   [--include-root-refs] [ --stdin | <pattern>... ]
 		   [--points-at=<object>]
 		   [--merged[=<object>]] [--no-merged[=<object>]]
 		   [--contains[=<object>]] [--no-contains[=<object>]]
@@ -105,6 +105,9 @@ TAB %(refname)`.
 	any excluded pattern(s) are shown. Matching is done using the
 	same rules as `<pattern>` above.
 
+--include-root-refs::
+	List root refs (HEAD and pseudorefs) apart from regular refs.
+
 FIELD NAMES
 -----------
 
diff --git a/Documentation/git-merge-tree.txt b/Documentation/git-merge-tree.txt
index b50acace3b..dd388fa21d 100644
--- a/Documentation/git-merge-tree.txt
+++ b/Documentation/git-merge-tree.txt
@@ -64,10 +64,13 @@ OPTIONS
 	share no common history.  This flag can be given to override that
 	check and make the merge proceed anyway.
 
---merge-base=<commit>::
+--merge-base=<tree-ish>::
 	Instead of finding the merge-bases for <branch1> and <branch2>,
 	specify a merge-base for the merge, and specifying multiple bases is
 	currently not supported. This option is incompatible with `--stdin`.
++
+As the merge-base is provided directly, <branch1> and <branch2> do not need
+to specify commits; trees are enough.
 
 [[OUTPUT]]
 OUTPUT
diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index 06206521fc..e7e725044d 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -607,7 +607,7 @@ The recommended way to create commits with squash markers is by using the
 linkgit:git-commit[1], which take the target commit as an argument and
 automatically fill in the subject line of the new commit from that.
 +
-Settting configuration variable `rebase.autoSquash` to true enables
+Setting configuration variable `rebase.autoSquash` to true enables
 auto-squashing by default for interactive rebase.  The `--no-autosquash`
 option can be used to override that setting.
 +
diff --git a/Documentation/git-reflog.txt b/Documentation/git-reflog.txt
index ec64cbff4c..a929c52982 100644
--- a/Documentation/git-reflog.txt
+++ b/Documentation/git-reflog.txt
@@ -10,6 +10,7 @@ SYNOPSIS
 --------
 [verse]
 'git reflog' [show] [<log-options>] [<ref>]
+'git reflog list'
 'git reflog expire' [--expire=<time>] [--expire-unreachable=<time>]
 	[--rewrite] [--updateref] [--stale-fix]
 	[--dry-run | -n] [--verbose] [--all [--single-worktree] | <refs>...]
@@ -39,6 +40,8 @@ actions, and in addition the `HEAD` reflog records branch switching.
 `git reflog show` is an alias for `git log -g --abbrev-commit
 --pretty=oneline`; see linkgit:git-log[1] for more information.
 
+The "list" subcommand lists all refs which have a corresponding reflog.
+
 The "expire" subcommand prunes older reflog entries. Entries older
 than `expire` time, or entries older than `expire-unreachable` time
 and not reachable from the current tip, are removed from the reflog.
diff --git a/Documentation/git-remote.txt b/Documentation/git-remote.txt
index 1dec314834..932a5c3ea4 100644
--- a/Documentation/git-remote.txt
+++ b/Documentation/git-remote.txt
@@ -35,7 +35,7 @@ OPTIONS
 -v::
 --verbose::
 	Be a little more verbose and show remote url after name.
-	For promisor remotes, also show which filter (`blob:none` etc.)
+	For promisor remotes, also show which filters (`blob:none` etc.)
 	are configured.
 	NOTE: This must be placed between `remote` and subcommand.
 
diff --git a/Documentation/git-rev-parse.txt b/Documentation/git-rev-parse.txt
index 546faf9017..5d83dd36da 100644
--- a/Documentation/git-rev-parse.txt
+++ b/Documentation/git-rev-parse.txt
@@ -9,7 +9,7 @@ git-rev-parse - Pick out and massage parameters
 SYNOPSIS
 --------
 [verse]
-'git rev-parse' [<options>] <args>...
+'git rev-parse' [<options>] <arg>...
 
 DESCRIPTION
 -----------
@@ -130,7 +130,7 @@ for another option.
 	'git diff-{asterisk}'). In contrast to the `--sq-quote` option,
 	the command input is still interpreted as usual.
 
---short[=length]::
+--short[=<length>]::
 	Same as `--verify` but shortens the object name to a unique
 	prefix with at least `length` characters. The minimum length
 	is 4, the default is the effective value of the `core.abbrev`
@@ -165,9 +165,9 @@ Options for Objects
 --all::
 	Show all refs found in `refs/`.
 
---branches[=pattern]::
---tags[=pattern]::
---remotes[=pattern]::
+--branches[=<pattern>]::
+--tags[=<pattern>]::
+--remotes[=<pattern>]::
 	Show all branches, tags, or remote-tracking branches,
 	respectively (i.e., refs found in `refs/heads`,
 	`refs/tags`, or `refs/remotes`, respectively).
@@ -176,7 +176,7 @@ If a `pattern` is given, only refs matching the given shell glob are
 shown.  If the pattern does not contain a globbing character (`?`,
 `*`, or `[`), it is turned into a prefix match by appending `/*`.
 
---glob=pattern::
+--glob=<pattern>::
 	Show all refs matching the shell glob pattern `pattern`. If
 	the pattern does not start with `refs/`, this is automatically
 	prepended.  If the pattern does not contain a globbing
@@ -197,7 +197,7 @@ respectively, and they must begin with `refs/` when applied to `--glob`
 or `--all`. If a trailing '/{asterisk}' is intended, it must be given
 explicitly.
 
---exclude-hidden=[fetch|receive|uploadpack]::
+--exclude-hidden=(fetch|receive|uploadpack)::
 	Do not include refs that would be hidden by `git-fetch`,
 	`git-receive-pack` or `git-upload-pack` by consulting the appropriate
 	`fetch.hideRefs`, `receive.hideRefs` or `uploadpack.hideRefs`
@@ -314,17 +314,17 @@ The following options are unaffected by `--path-format`:
 Other Options
 ~~~~~~~~~~~~~
 
---since=datestring::
---after=datestring::
+--since=<datestring>::
+--after=<datestring>::
 	Parse the date string, and output the corresponding
 	--max-age= parameter for 'git rev-list'.
 
---until=datestring::
---before=datestring::
+--until=<datestring>::
+--before=<datestring>::
 	Parse the date string, and output the corresponding
 	--min-age= parameter for 'git rev-list'.
 
-<args>...::
+<arg>...::
 	Flags and parameters to be parsed.
 
 
diff --git a/Documentation/git-send-email.txt b/Documentation/git-send-email.txt
index d1ef6a204e..8264f87380 100644
--- a/Documentation/git-send-email.txt
+++ b/Documentation/git-send-email.txt
@@ -138,7 +138,7 @@ Note that no attempts whatsoever are made to validate the encoding.
 
 --compose-encoding=<encoding>::
 	Specify encoding of compose message. Default is the value of the
-	'sendemail.composeencoding'; if that is unspecified, UTF-8 is assumed.
+	'sendemail.composeEncoding'; if that is unspecified, UTF-8 is assumed.
 
 --transfer-encoding=(7bit|8bit|quoted-printable|base64|auto)::
 	Specify the transfer encoding to be used to send the message over SMTP.
@@ -174,7 +174,7 @@ Sending
 	Specify a command to run to send the email. The command should
 	be sendmail-like; specifically, it must support the `-i` option.
 	The command will be executed in the shell if necessary.  Default
-	is the value of `sendemail.sendmailcmd`.  If unspecified, and if
+	is the value of `sendemail.sendmailCmd`.  If unspecified, and if
 	--smtp-server is also unspecified, git-send-email will search
 	for `sendmail` in `/usr/sbin`, `/usr/lib` and $PATH.
 
@@ -269,7 +269,7 @@ must be used for each option.
 	certificates concatenated together: see verify(1) -CAfile and
 	-CApath for more information on these). Set it to an empty string
 	to disable certificate verification. Defaults to the value of the
-	`sendemail.smtpsslcertpath` configuration variable, if set, or the
+	`sendemail.smtpSSLCertPath` configuration variable, if set, or the
 	backing SSL library's compiled-in default otherwise (which should
 	be the best choice on most platforms).
 
@@ -313,7 +313,7 @@ Automating
 	Specify a command to execute once per patch file which
 	should generate patch file specific "To:" entries.
 	Output of this command must be single email address per line.
-	Default is the value of 'sendemail.tocmd' configuration value.
+	Default is the value of 'sendemail.toCmd' configuration value.
 
 --cc-cmd=<command>::
 	Specify a command to execute once per patch file which
@@ -348,19 +348,19 @@ Automating
 
 --[no-]signed-off-by-cc::
 	If this is set, add emails found in the `Signed-off-by` trailer or Cc: lines to the
-	cc list. Default is the value of `sendemail.signedoffbycc` configuration
+	cc list. Default is the value of `sendemail.signedOffByCc` configuration
 	value; if that is unspecified, default to --signed-off-by-cc.
 
 --[no-]cc-cover::
 	If this is set, emails found in Cc: headers in the first patch of
 	the series (typically the cover letter) are added to the cc list
-	for each email set. Default is the value of 'sendemail.cccover'
+	for each email set. Default is the value of 'sendemail.ccCover'
 	configuration value; if that is unspecified, default to --no-cc-cover.
 
 --[no-]to-cover::
 	If this is set, emails found in To: headers in the first patch of
 	the series (typically the cover letter) are added to the to list
-	for each email set. Default is the value of 'sendemail.tocover'
+	for each email set. Default is the value of 'sendemail.toCover'
 	configuration value; if that is unspecified, default to --no-to-cover.
 
 --suppress-cc=<category>::
@@ -384,7 +384,7 @@ Automating
 - 'all' will suppress all auto cc values.
 --
 +
-Default is the value of `sendemail.suppresscc` configuration value; if
+Default is the value of `sendemail.suppressCc` configuration value; if
 that is unspecified, default to 'self' if --suppress-from is
 specified, as well as 'body' if --no-signed-off-cc is specified.
 
@@ -471,7 +471,7 @@ Information
 	Instead of the normal operation, dump the shorthand alias names from
 	the configured alias file(s), one per line in alphabetical order. Note
 	that this only includes the alias name and not its expanded email addresses.
-	See 'sendemail.aliasesfile' for more information about aliases.
+	See 'sendemail.aliasesFile' for more information about aliases.
 
 
 CONFIGURATION
diff --git a/Documentation/git.txt b/Documentation/git.txt
index 0d25224c96..e6b766d5c3 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -174,8 +174,17 @@ If you just want to run git as if it was started in `<path>` then use
 	directory.
 
 --no-replace-objects::
-	Do not use replacement refs to replace Git objects. See
-	linkgit:git-replace[1] for more information.
+	Do not use replacement refs to replace Git objects.
+	This is equivalent to exporting the `GIT_NO_REPLACE_OBJECTS`
+	environment variable with any value.
+	See linkgit:git-replace[1] for more information.
+
+--no-lazy-fetch::
+	Do not fetch missing objects from the promisor remote on
+	demand.  Useful together with `git cat-file -e <object>` to
+	see if the object is locally available.
+	This is equivalent to setting the `GIT_NO_LAZY_FETCH`
+	environment variable to `1`.
 
 --literal-pathspecs::
 	Treat pathspecs literally (i.e. no globbing, no pathspec magic).
@@ -872,6 +881,10 @@ for full details.
 	header and packfile URIs. Set this Boolean environment variable to false to prevent this
 	redaction.
 
+`GIT_NO_REPLACE_OBJECTS`::
+	Setting and exporting this environment variable tells Git to
+	ignore replacement refs and do not replace Git objects.
+
 `GIT_LITERAL_PATHSPECS`::
 	Setting this Boolean environment variable to true will cause Git to treat all
 	pathspecs literally, rather than as glob patterns. For example,
@@ -893,6 +906,11 @@ for full details.
 	Setting this Boolean environment variable to true will cause Git to treat all
 	pathspecs as case-insensitive.
 
+`GIT_NO_LAZY_FETCH`::
+	Setting this Boolean environment variable to true tells Git
+	not to lazily fetch missing objects from the promisor remote
+	on demand.
+
 `GIT_REFLOG_ACTION`::
 	When a ref is updated, reflog entries are created to keep
 	track of the reason why the ref was updated (which is
diff --git a/Documentation/gitcli.txt b/Documentation/gitcli.txt
index e5fac94322..7c709324ba 100644
--- a/Documentation/gitcli.txt
+++ b/Documentation/gitcli.txt
@@ -81,9 +81,6 @@ you will.
 Here are the rules regarding the "flags" that you should follow when you are
 scripting Git:
 
- * It's preferred to use the non-dashed form of Git commands, which means that
-   you should prefer `git foo` to `git-foo`.
-
  * Splitting short options to separate words (prefer `git foo -a -b`
    to `git foo -ab`, the latter may not even work).
 
diff --git a/Documentation/gitprotocol-v2.txt b/Documentation/gitprotocol-v2.txt
index 0b800abd56..414bc625d5 100644
--- a/Documentation/gitprotocol-v2.txt
+++ b/Documentation/gitprotocol-v2.txt
@@ -346,7 +346,8 @@ the 'wanted-refs' section in the server's response as explained below.
     want-ref <ref>
 	Indicates to the server that the client wants to retrieve a
 	particular ref, where <ref> is the full name of a ref on the
-	server.
+	server.  It is a protocol error to send want-ref for the
+	same ref more than once.
 
 If the 'sideband-all' feature is advertised, the following argument can be
 included in the client's request:
@@ -361,7 +362,8 @@ included in the client's request:
 If the 'packfile-uris' feature is advertised, the following argument
 can be included in the client's request as well as the potential
 addition of the 'packfile-uris' section in the server's response as
-explained below.
+explained below. Note that at most one `packfile-uris` line can be sent
+to the server.
 
     packfile-uris <comma-separated-list-of-protocols>
 	Indicates to the server that the client is willing to receive
diff --git a/Documentation/mergetools/vimdiff.txt b/Documentation/mergetools/vimdiff.txt
index d1a4c468e6..befa86d692 100644
--- a/Documentation/mergetools/vimdiff.txt
+++ b/Documentation/mergetools/vimdiff.txt
@@ -177,7 +177,8 @@ Instead of `--tool=vimdiff`, you can also use one of these other variants:
 
 When using these variants, in order to specify a custom layout you will have to
 set configuration variables `mergetool.gvimdiff.layout` and
-`mergetool.nvimdiff.layout` instead of `mergetool.vimdiff.layout`
+`mergetool.nvimdiff.layout` instead of `mergetool.vimdiff.layout` (though the
+latter will be used as fallback if the variant-specific one is not set).
 
 In addition, for backwards compatibility with previous Git versions, you can
 also append `1`, `2` or `3` to either `vimdiff` or any of the variants (ex:
diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index a583b52c61..408d9314d0 100644
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt
@@ -341,8 +341,11 @@ See also linkgit:git-reflog[1].
 Under `--pretty=reference`, this information will not be shown at all.
 
 --merge::
-	After a failed merge, show refs that touch files having a
-	conflict and don't exist on all heads to merge.
+	Show commits touching conflicted paths in the range `HEAD...<other>`,
+	where `<other>` is the first existing pseudoref in `MERGE_HEAD`,
+	`CHERRY_PICK_HEAD`, `REVERT_HEAD` or `REBASE_HEAD`. Only works
+	when the index has unmerged entries. This option can be used to show
+	relevant commits when resolving conflicts from a 3-way merge.
 
 --boundary::
 	Output excluded boundary commits. Boundary commits are
@@ -1019,6 +1022,10 @@ Unexpected missing objects will raise an error.
 +
 The form '--missing=print' is like 'allow-any', but will also print a
 list of the missing objects.  Object IDs are prefixed with a ``?'' character.
++
+If some tips passed to the traversal are missing, they will be
+considered as missing too, and the traversal will ignore them. In case
+we cannot get their Object ID though, an error will be raised.
 
 --exclude-promisor-objects::
 	(For internal use only.)  Prefilter object traversal at
diff --git a/GIT-VERSION-GEN b/GIT-VERSION-GEN
index c9d1d29082..df788c764b 100755
--- a/GIT-VERSION-GEN
+++ b/GIT-VERSION-GEN
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 GVF=GIT-VERSION-FILE
-DEF_VER=v2.44.0
+DEF_VER=v2.44.GIT
 
 LF='
 '
diff --git a/advice.c b/advice.c
index 6e9098ff08..4ba64ee5b2 100644
--- a/advice.c
+++ b/advice.c
@@ -79,6 +79,7 @@ static struct {
 	[ADVICE_STATUS_U_OPTION]			= { "statusUoption" },
 	[ADVICE_SUBMODULES_NOT_UPDATED] 		= { "submodulesNotUpdated" },
 	[ADVICE_SUBMODULE_ALTERNATE_ERROR_STRATEGY_DIE] = { "submoduleAlternateErrorStrategyDie" },
+	[ADVICE_SUBMODULE_MERGE_CONFLICT]               = { "submoduleMergeConflict" },
 	[ADVICE_SUGGEST_DETACHING_HEAD]			= { "suggestDetachingHead" },
 	[ADVICE_UPDATE_SPARSE_PATH]			= { "updateSparsePath" },
 	[ADVICE_WAITING_FOR_EDITOR]			= { "waitingForEditor" },
diff --git a/advice.h b/advice.h
index 9d4f49ae38..7d0a821f5c 100644
--- a/advice.h
+++ b/advice.h
@@ -47,6 +47,7 @@ enum advice_type {
 	ADVICE_STATUS_U_OPTION,
 	ADVICE_SUBMODULES_NOT_UPDATED,
 	ADVICE_SUBMODULE_ALTERNATE_ERROR_STRATEGY_DIE,
+	ADVICE_SUBMODULE_MERGE_CONFLICT,
 	ADVICE_SUGGEST_DETACHING_HEAD,
 	ADVICE_UPDATE_SPARSE_PATH,
 	ADVICE_WAITING_FOR_EDITOR,
diff --git a/apply.c b/apply.c
index 355e2b0f2f..432837a674 100644
--- a/apply.c
+++ b/apply.c
@@ -77,7 +77,8 @@ static int parse_whitespace_option(struct apply_state *state, const char *option
 		return 0;
 	}
 	/*
-	 * Please update $__git_whitespacelist in git-completion.bash
+	 * Please update $__git_whitespacelist in git-completion.bash,
+	 * Documentation/git-apply.txt, and Documentation/git-am.txt
 	 * when you add new options.
 	 */
 	return error(_("unrecognized whitespace option '%s'"), option);
diff --git a/bisect.c b/bisect.c
index f75e50c339..60aae2fe50 100644
--- a/bisect.c
+++ b/bisect.c
@@ -836,10 +836,11 @@ static void handle_skipped_merge_base(const struct object_id *mb)
 static enum bisect_error check_merge_bases(int rev_nr, struct commit **rev, int no_checkout)
 {
 	enum bisect_error res = BISECT_OK;
-	struct commit_list *result;
+	struct commit_list *result = NULL;
 
-	result = repo_get_merge_bases_many(the_repository, rev[0], rev_nr - 1,
-					   rev + 1);
+	if (repo_get_merge_bases_many(the_repository, rev[0], rev_nr - 1,
+				      rev + 1, &result) < 0)
+		exit(128);
 
 	for (; result; result = result->next) {
 		const struct object_id *mb = &result->item->object.oid;
diff --git a/builtin/add.c b/builtin/add.c
index ada7719561..393c10cbcf 100644
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -115,7 +115,7 @@ static int refresh(int verbose, const struct pathspec *pathspec)
 	int i, ret = 0;
 	char *skip_worktree_seen = NULL;
 	struct string_list only_match_skip_worktree = STRING_LIST_INIT_NODUP;
-	int flags = REFRESH_IGNORE_SKIP_WORKTREE |
+	unsigned int flags = REFRESH_IGNORE_SKIP_WORKTREE |
 		    (verbose ? REFRESH_IN_PORCELAIN : REFRESH_QUIET);
 
 	seen = xcalloc(pathspec->nr, 1);
diff --git a/builtin/branch.c b/builtin/branch.c
index cfb63cce5f..b3cbb7fd44 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -158,6 +158,8 @@ static int branch_merged(int kind, const char *name,
 
 	merged = reference_rev ? repo_in_merge_bases(the_repository, rev,
 						     reference_rev) : 0;
+	if (merged < 0)
+		exit(128);
 
 	/*
 	 * After the safety valve is fully redefined to "check with
@@ -166,9 +168,13 @@ static int branch_merged(int kind, const char *name,
 	 * any of the following code, but during the transition period,
 	 * a gentle reminder is in order.
 	 */
-	if ((head_rev != reference_rev) &&
-	    (head_rev ? repo_in_merge_bases(the_repository, rev, head_rev) : 0) != merged) {
-		if (merged)
+	if (head_rev != reference_rev) {
+		int expect = head_rev ? repo_in_merge_bases(the_repository, rev, head_rev) : 0;
+		if (expect < 0)
+			exit(128);
+		if (expect == merged)
+			; /* okay */
+		else if (merged)
 			warning(_("deleting branch '%s' that has been merged to\n"
 				"         '%s', but not yet merged to HEAD"),
 				name, reference_name);
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 067c251933..15293a3013 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -704,7 +704,8 @@ static int reset_tree(struct tree *tree, const struct checkout_opts *o,
 	init_checkout_metadata(&opts.meta, info->refname,
 			       info->commit ? &info->commit->object.oid : null_oid(),
 			       NULL);
-	parse_tree(tree);
+	if (parse_tree(tree) < 0)
+		return 128;
 	init_tree_desc(&tree_desc, tree->buffer, tree->size);
 	switch (unpack_trees(1, &tree_desc, &opts)) {
 	case -2:
@@ -783,9 +784,15 @@ static int merge_working_tree(const struct checkout_opts *opts,
 		if (new_branch_info->commit)
 			BUG("'switch --orphan' should never accept a commit as starting point");
 		new_tree = parse_tree_indirect(the_hash_algo->empty_tree);
-	} else
+		if (!new_tree)
+			BUG("unable to read empty tree");
+	} else {
 		new_tree = repo_get_commit_tree(the_repository,
 						new_branch_info->commit);
+		if (!new_tree)
+			return error(_("unable to read tree (%s)"),
+				     oid_to_hex(&new_branch_info->commit->object.oid));
+	}
 	if (opts->discard_changes) {
 		ret = reset_tree(new_tree, opts, 1, writeout_error, new_branch_info);
 		if (ret)
@@ -820,7 +827,8 @@ static int merge_working_tree(const struct checkout_opts *opts,
 				oid_to_hex(old_commit_oid));
 
 		init_tree_desc(&trees[0], tree->buffer, tree->size);
-		parse_tree(new_tree);
+		if (parse_tree(new_tree) < 0)
+			exit(128);
 		tree = new_tree;
 		init_tree_desc(&trees[1], tree->buffer, tree->size);
 
@@ -1240,10 +1248,15 @@ static void setup_new_branch_info_and_source_tree(
 	if (!new_branch_info->commit) {
 		/* not a commit */
 		*source_tree = parse_tree_indirect(rev);
+		if (!*source_tree)
+			die(_("unable to read tree (%s)"), oid_to_hex(rev));
 	} else {
 		parse_commit_or_die(new_branch_info->commit);
 		*source_tree = repo_get_commit_tree(the_repository,
 						    new_branch_info->commit);
+		if (!*source_tree)
+			die(_("unable to read tree (%s)"),
+			    oid_to_hex(&new_branch_info->commit->object.oid));
 	}
 }
 
diff --git a/builtin/clean.c b/builtin/clean.c
index d90766cad3..29efe84153 100644
--- a/builtin/clean.c
+++ b/builtin/clean.c
@@ -25,7 +25,7 @@
 #include "help.h"
 #include "prompt.h"
 
-static int force = -1; /* unset */
+static int require_force = -1; /* unset */
 static int interactive;
 static struct string_list del_list = STRING_LIST_INIT_DUP;
 static unsigned int colopts;
@@ -128,7 +128,7 @@ static int git_clean_config(const char *var, const char *value,
 	}
 
 	if (!strcmp(var, "clean.requireforce")) {
-		force = !git_config_bool(var, value);
+		require_force = git_config_bool(var, value);
 		return 0;
 	}
 
@@ -920,7 +920,7 @@ int cmd_clean(int argc, const char **argv, const char *prefix)
 {
 	int i, res;
 	int dry_run = 0, remove_directories = 0, quiet = 0, ignored = 0;
-	int ignored_only = 0, config_set = 0, errors = 0, gone = 1;
+	int ignored_only = 0, force = 0, errors = 0, gone = 1;
 	int rm_flags = REMOVE_DIR_KEEP_NESTED_GIT;
 	struct strbuf abs_path = STRBUF_INIT;
 	struct dir_struct dir = DIR_INIT;
@@ -946,22 +946,12 @@ int cmd_clean(int argc, const char **argv, const char *prefix)
 	};
 
 	git_config(git_clean_config, NULL);
-	if (force < 0)
-		force = 0;
-	else
-		config_set = 1;
 
 	argc = parse_options(argc, argv, prefix, options, builtin_clean_usage,
 			     0);
 
-	if (!interactive && !dry_run && !force) {
-		if (config_set)
-			die(_("clean.requireForce set to true and neither -i, -n, nor -f given; "
-				  "refusing to clean"));
-		else
-			die(_("clean.requireForce defaults to true and neither -i, -n, nor -f given;"
-				  " refusing to clean"));
-	}
+	if (require_force != 0 && !force && !interactive && !dry_run)
+		die(_("clean.requireForce is true and -f not given: refusing to clean"));
 
 	if (force > 1)
 		rm_flags = 0;
diff --git a/builtin/clone.c b/builtin/clone.c
index bad1b70ce8..93892ab568 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -738,7 +738,8 @@ static int checkout(int submodule_progress, int filter_submodules)
 	tree = parse_tree_indirect(&oid);
 	if (!tree)
 		die(_("unable to parse commit %s"), oid_to_hex(&oid));
-	parse_tree(tree);
+	if (parse_tree(tree) < 0)
+		exit(128);
 	init_tree_desc(&t, tree->buffer, tree->size);
 	if (unpack_trees(1, &t, &opts) < 0)
 		die(_("unable to checkout working tree"));
@@ -926,6 +927,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	struct ref *mapped_refs = NULL;
 	const struct ref *ref;
 	struct strbuf key = STRBUF_INIT;
+	struct strbuf buf = STRBUF_INIT;
 	struct strbuf branch_top = STRBUF_INIT, reflog_msg = STRBUF_INIT;
 	struct transport *transport = NULL;
 	const char *src_ref_prefix = "refs/heads/";
@@ -1125,6 +1127,50 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 		git_dir = real_git_dir;
 	}
 
+	/*
+	 * We have a chicken-and-egg situation between initializing the refdb
+	 * and spawning transport helpers:
+	 *
+	 *   - Initializing the refdb requires us to know about the object
+	 *     format. We thus have to spawn the transport helper to learn
+	 *     about it.
+	 *
+	 *   - The transport helper may want to access the Git repository. But
+	 *     because the refdb has not been initialized, we don't have "HEAD"
+	 *     or "refs/". Thus, the helper cannot find the Git repository.
+	 *
+	 * Ideally, we would have structured the helper protocol such that it's
+	 * mandatory for the helper to first announce its capabilities without
+	 * yet assuming a fully initialized repository. Like that, we could
+	 * have added a "lazy-refdb-init" capability that announces whether the
+	 * helper is ready to handle not-yet-initialized refdbs. If any helper
+	 * didn't support them, we would have fully initialized the refdb with
+	 * the SHA1 object format, but later on bailed out if we found out that
+	 * the remote repository used a different object format.
+	 *
+	 * But we didn't, and thus we use the following workaround to partially
+	 * initialize the repository's refdb such that it can be discovered by
+	 * Git commands. To do so, we:
+	 *
+	 *   - Create an invalid HEAD ref pointing at "refs/heads/.invalid".
+	 *
+	 *   - Create the "refs/" directory.
+	 *
+	 *   - Set up the ref storage format and repository version as
+	 *     required.
+	 *
+	 * This is sufficient for Git commands to discover the Git directory.
+	 */
+	initialize_repository_version(GIT_HASH_UNKNOWN,
+				      the_repository->ref_storage_format, 1);
+
+	strbuf_addf(&buf, "%s/HEAD", git_dir);
+	write_file(buf.buf, "ref: refs/heads/.invalid");
+
+	strbuf_reset(&buf);
+	strbuf_addf(&buf, "%s/refs", git_dir);
+	safe_create_dir(buf.buf, 1);
+
 	/*
 	 * additional config can be injected with -c, make sure it's included
 	 * after init_db, which clears the entire config environment.
@@ -1453,6 +1499,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	free(remote_name);
 	strbuf_release(&reflog_msg);
 	strbuf_release(&branch_top);
+	strbuf_release(&buf);
 	strbuf_release(&key);
 	free_refs(mapped_refs);
 	free_refs(remote_head_points_at);
diff --git a/builtin/commit.c b/builtin/commit.c
index 6d1fa71676..a91197245f 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -331,7 +331,8 @@ static void create_base_index(const struct commit *current_head)
 	tree = parse_tree_indirect(&current_head->object.oid);
 	if (!tree)
 		die(_("failed to unpack HEAD tree object"));
-	parse_tree(tree);
+	if (parse_tree(tree) < 0)
+		exit(128);
 	init_tree_desc(&t, tree->buffer, tree->size);
 	if (unpack_trees(1, &t, &opts))
 		exit(128); /* We've already reported the error, finish dying */
@@ -737,7 +738,6 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 	const char *hook_arg2 = NULL;
 	int clean_message_contents = (cleanup_mode != COMMIT_MSG_CLEANUP_NONE);
 	int old_display_comment_prefix;
-	int merge_contains_scissors = 0;
 	int invoked_hook;
 
 	/* This checks and barfs if author is badly specified */
@@ -841,7 +841,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 		    wt_status_locate_end(sb.buf + merge_msg_start,
 					 sb.len - merge_msg_start) <
 				sb.len - merge_msg_start)
-			merge_contains_scissors = 1;
+			s->added_cut_line = 1;
 	} else if (!stat(git_path_squash_msg(the_repository), &statbuf)) {
 		if (strbuf_read_file(&sb, git_path_squash_msg(the_repository), 0) < 0)
 			die_errno(_("could not read SQUASH_MSG"));
@@ -924,9 +924,8 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 			  " yourself if you want to.\n"
 			  "An empty message aborts the commit.\n");
 		if (whence != FROM_COMMIT) {
-			if (cleanup_mode == COMMIT_MSG_CLEANUP_SCISSORS &&
-				!merge_contains_scissors)
-				wt_status_add_cut_line(s->fp);
+			if (cleanup_mode == COMMIT_MSG_CLEANUP_SCISSORS)
+				wt_status_add_cut_line(s);
 			status_printf_ln(
 				s, GIT_COLOR_NORMAL,
 				whence == FROM_MERGE ?
@@ -946,8 +945,8 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 		if (cleanup_mode == COMMIT_MSG_CLEANUP_ALL)
 			status_printf(s, GIT_COLOR_NORMAL, hint_cleanup_all, comment_line_char);
 		else if (cleanup_mode == COMMIT_MSG_CLEANUP_SCISSORS) {
-			if (whence == FROM_COMMIT && !merge_contains_scissors)
-				wt_status_add_cut_line(s->fp);
+			if (whence == FROM_COMMIT)
+				wt_status_add_cut_line(s);
 		} else /* COMMIT_MSG_CLEANUP_SPACE, that is. */
 			status_printf(s, GIT_COLOR_NORMAL, hint_cleanup_space, comment_line_char);
 
diff --git a/builtin/fast-import.c b/builtin/fast-import.c
index 92eda20683..71a195ca22 100644
--- a/builtin/fast-import.c
+++ b/builtin/fast-import.c
@@ -1625,6 +1625,7 @@ static int update_branch(struct branch *b)
 		oidclr(&old_oid);
 	if (!force_update && !is_null_oid(&old_oid)) {
 		struct commit *old_cmit, *new_cmit;
+		int ret;
 
 		old_cmit = lookup_commit_reference_gently(the_repository,
 							  &old_oid, 0);
@@ -1633,7 +1634,10 @@ static int update_branch(struct branch *b)
 		if (!old_cmit || !new_cmit)
 			return error("Branch %s is missing commits.", b->name);
 
-		if (!repo_in_merge_bases(the_repository, old_cmit, new_cmit)) {
+		ret = repo_in_merge_bases(the_repository, old_cmit, new_cmit);
+		if (ret < 0)
+			exit(128);
+		if (!ret) {
 			warning("Not updating %s"
 				" (new tip %s does not contain %s)",
 				b->name, oid_to_hex(&b->oid),
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 3aedfd1bb6..46a793411a 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -448,9 +448,8 @@ static void filter_prefetch_refspec(struct refspec *rs)
 			continue;
 		if (!rs->items[i].dst ||
 		    (rs->items[i].src &&
-		     !strncmp(rs->items[i].src,
-			      ref_namespace[NAMESPACE_TAGS].ref,
-			      strlen(ref_namespace[NAMESPACE_TAGS].ref)))) {
+		     starts_with(rs->items[i].src,
+				 ref_namespace[NAMESPACE_TAGS].ref))) {
 			int j;
 
 			free(rs->items[i].src);
@@ -982,6 +981,8 @@ static int update_local_ref(struct ref *ref,
 		uint64_t t_before = getnanotime();
 		fast_forward = repo_in_merge_bases(the_repository, current,
 						   updated);
+		if (fast_forward < 0)
+			exit(128);
 		forced_updates_ms += (getnanotime() - t_before) / 1000000;
 	} else {
 		fast_forward = 1;
diff --git a/builtin/for-each-ref.c b/builtin/for-each-ref.c
index 3885a9c28e..919282e12a 100644
--- a/builtin/for-each-ref.c
+++ b/builtin/for-each-ref.c
@@ -20,10 +20,10 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix)
 {
 	struct ref_sorting *sorting;
 	struct string_list sorting_options = STRING_LIST_INIT_DUP;
-	int icase = 0;
+	int icase = 0, include_root_refs = 0, from_stdin = 0;
 	struct ref_filter filter = REF_FILTER_INIT;
 	struct ref_format format = REF_FORMAT_INIT;
-	int from_stdin = 0;
+	unsigned int flags = FILTER_REFS_REGULAR;
 	struct strvec vec = STRVEC_INIT;
 
 	struct option opts[] = {
@@ -53,6 +53,7 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix)
 		OPT_NO_CONTAINS(&filter.no_commit, N_("print only refs which don't contain the commit")),
 		OPT_BOOL(0, "ignore-case", &icase, N_("sorting and filtering are case insensitive")),
 		OPT_BOOL(0, "stdin", &from_stdin, N_("read reference patterns from stdin")),
+		OPT_BOOL(0, "include-root-refs", &include_root_refs, N_("also include HEAD ref and pseudorefs")),
 		OPT_END(),
 	};
 
@@ -96,8 +97,11 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix)
 		filter.name_patterns = argv;
 	}
 
+	if (include_root_refs)
+		flags |= FILTER_REFS_ROOT_REFS;
+
 	filter.match_as_path = 1;
-	filter_and_format_refs(&filter, FILTER_REFS_ALL, sorting, &format);
+	filter_and_format_refs(&filter, flags, sorting, &format);
 
 	ref_filter_clear(&filter);
 	ref_sorting_release(sorting);
diff --git a/builtin/fsck.c b/builtin/fsck.c
index a7cf94f67e..f892487c9b 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -509,9 +509,7 @@ static int fsck_handle_reflog_ent(struct object_id *ooid, struct object_id *noid
 	return 0;
 }
 
-static int fsck_handle_reflog(const char *logname,
-			      const struct object_id *oid UNUSED,
-			      int flag UNUSED, void *cb_data)
+static int fsck_handle_reflog(const char *logname, void *cb_data)
 {
 	struct strbuf refname = STRBUF_INIT;
 
diff --git a/builtin/log.c b/builtin/log.c
index db1808d7c1..e5da0d1043 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -1625,7 +1625,7 @@ static struct commit *get_base_commit(const char *base_commit,
 {
 	struct commit *base = NULL;
 	struct commit **rev;
-	int i = 0, rev_nr = 0, auto_select, die_on_failure;
+	int i = 0, rev_nr = 0, auto_select, die_on_failure, ret;
 
 	switch (auto_base) {
 	case AUTO_BASE_NEVER:
@@ -1658,7 +1658,7 @@ static struct commit *get_base_commit(const char *base_commit,
 		struct branch *curr_branch = branch_get(NULL);
 		const char *upstream = branch_get_upstream(curr_branch, NULL);
 		if (upstream) {
-			struct commit_list *base_list;
+			struct commit_list *base_list = NULL;
 			struct commit *commit;
 			struct object_id oid;
 
@@ -1669,11 +1669,12 @@ static struct commit *get_base_commit(const char *base_commit,
 					return NULL;
 			}
 			commit = lookup_commit_or_die(&oid, "upstream base");
-			base_list = repo_get_merge_bases_many(the_repository,
-							      commit, total,
-							      list);
-			/* There should be one and only one merge base. */
-			if (!base_list || base_list->next) {
+			if (repo_get_merge_bases_many(the_repository,
+						      commit, total,
+						      list,
+						      &base_list) < 0 ||
+			    /* There should be one and only one merge base. */
+			    !base_list || base_list->next) {
 				if (die_on_failure) {
 					die(_("could not find exact merge base"));
 				} else {
@@ -1704,11 +1705,11 @@ static struct commit *get_base_commit(const char *base_commit,
 	 */
 	while (rev_nr > 1) {
 		for (i = 0; i < rev_nr / 2; i++) {
-			struct commit_list *merge_base;
-			merge_base = repo_get_merge_bases(the_repository,
-							  rev[2 * i],
-							  rev[2 * i + 1]);
-			if (!merge_base || merge_base->next) {
+			struct commit_list *merge_base = NULL;
+			if (repo_get_merge_bases(the_repository,
+						 rev[2 * i],
+						 rev[2 * i + 1], &merge_base) < 0 ||
+			    !merge_base || merge_base->next) {
 				if (die_on_failure) {
 					die(_("failed to find exact merge base"));
 				} else {
@@ -1725,7 +1726,10 @@ static struct commit *get_base_commit(const char *base_commit,
 		rev_nr = DIV_ROUND_UP(rev_nr, 2);
 	}
 
-	if (!repo_in_merge_bases(the_repository, base, rev[0])) {
+	ret = repo_in_merge_bases(the_repository, base, rev[0]);
+	if (ret < 0)
+		exit(128);
+	if (!ret) {
 		if (die_on_failure) {
 			die(_("base commit should be the ancestor of revision list"));
 		} else {
diff --git a/builtin/merge-base.c b/builtin/merge-base.c
index d26e8fbf6f..5a8e729502 100644
--- a/builtin/merge-base.c
+++ b/builtin/merge-base.c
@@ -10,10 +10,13 @@
 
 static int show_merge_base(struct commit **rev, int rev_nr, int show_all)
 {
-	struct commit_list *result, *r;
+	struct commit_list *result = NULL, *r;
 
-	result = repo_get_merge_bases_many_dirty(the_repository, rev[0],
-						 rev_nr - 1, rev + 1);
+	if (repo_get_merge_bases_many_dirty(the_repository, rev[0],
+					    rev_nr - 1, rev + 1, &result) < 0) {
+		free_commit_list(result);
+		return -1;
+	}
 
 	if (!result)
 		return 1;
@@ -74,13 +77,17 @@ static int handle_independent(int count, const char **args)
 static int handle_octopus(int count, const char **args, int show_all)
 {
 	struct commit_list *revs = NULL;
-	struct commit_list *result, *rev;
+	struct commit_list *result = NULL, *rev;
 	int i;
 
 	for (i = count - 1; i >= 0; i--)
 		commit_list_insert(get_commit_reference(args[i]), &revs);
 
-	result = get_octopus_merge_bases(revs);
+	if (get_octopus_merge_bases(revs, &result) < 0) {
+		free_commit_list(revs);
+		free_commit_list(result);
+		return 128;
+	}
 	free_commit_list(revs);
 	reduce_heads_replace(&result);
 
@@ -100,12 +107,16 @@ static int handle_octopus(int count, const char **args, int show_all)
 static int handle_is_ancestor(int argc, const char **argv)
 {
 	struct commit *one, *two;
+	int ret;
 
 	if (argc != 2)
 		die("--is-ancestor takes exactly two commits");
 	one = get_commit_reference(argv[0]);
 	two = get_commit_reference(argv[1]);
-	if (repo_in_merge_bases(the_repository, one, two))
+	ret = repo_in_merge_bases(the_repository, one, two);
+	if (ret < 0)
+		exit(128);
+	if (ret)
 		return 0;
 	else
 		return 1;
diff --git a/builtin/merge-tree.c b/builtin/merge-tree.c
index 3bdec53fbe..05d0cad554 100644
--- a/builtin/merge-tree.c
+++ b/builtin/merge-tree.c
@@ -429,41 +429,56 @@ static int real_merge(struct merge_tree_options *o,
 	struct merge_options opt;
 
 	copy_merge_options(&opt, &o->merge_options);
-	parent1 = get_merge_parent(branch1);
-	if (!parent1)
-		help_unknown_ref(branch1, "merge-tree",
-				 _("not something we can merge"));
-
-	parent2 = get_merge_parent(branch2);
-	if (!parent2)
-		help_unknown_ref(branch2, "merge-tree",
-				 _("not something we can merge"));
-
 	opt.show_rename_progress = 0;
 
 	opt.branch1 = branch1;
 	opt.branch2 = branch2;
 
 	if (merge_base) {
-		struct commit *base_commit;
 		struct tree *base_tree, *parent1_tree, *parent2_tree;
 
-		base_commit = lookup_commit_reference_by_name(merge_base);
-		if (!base_commit)
-			die(_("could not lookup commit '%s'"), merge_base);
+		/*
+		 * We actually only need the trees because we already
+		 * have a merge base.
+		 */
+		struct object_id base_oid, head_oid, merge_oid;
+
+		if (repo_get_oid_treeish(the_repository, merge_base, &base_oid))
+			die(_("could not parse as tree '%s'"), merge_base);
+		base_tree = parse_tree_indirect(&base_oid);
+		if (!base_tree)
+			die(_("unable to read tree (%s)"), oid_to_hex(&base_oid));
+		if (repo_get_oid_treeish(the_repository, branch1, &head_oid))
+			die(_("could not parse as tree '%s'"), branch1);
+		parent1_tree = parse_tree_indirect(&head_oid);
+		if (!parent1_tree)
+			die(_("unable to read tree (%s)"), oid_to_hex(&head_oid));
+		if (repo_get_oid_treeish(the_repository, branch2, &merge_oid))
+			die(_("could not parse as tree '%s'"), branch2);
+		parent2_tree = parse_tree_indirect(&merge_oid);
+		if (!parent2_tree)
+			die(_("unable to read tree (%s)"), oid_to_hex(&merge_oid));
 
 		opt.ancestor = merge_base;
-		base_tree = repo_get_commit_tree(the_repository, base_commit);
-		parent1_tree = repo_get_commit_tree(the_repository, parent1);
-		parent2_tree = repo_get_commit_tree(the_repository, parent2);
 		merge_incore_nonrecursive(&opt, base_tree, parent1_tree, parent2_tree, &result);
 	} else {
+		parent1 = get_merge_parent(branch1);
+		if (!parent1)
+			help_unknown_ref(branch1, "merge-tree",
+					 _("not something we can merge"));
+
+		parent2 = get_merge_parent(branch2);
+		if (!parent2)
+			help_unknown_ref(branch2, "merge-tree",
+					 _("not something we can merge"));
+
 		/*
 		 * Get the merge bases, in reverse order; see comment above
 		 * merge_incore_recursive in merge-ort.h
 		 */
-		merge_bases = repo_get_merge_bases(the_repository, parent1,
-						   parent2);
+		if (repo_get_merge_bases(the_repository, parent1,
+					 parent2, &merge_bases) < 0)
+			exit(128);
 		if (!merge_bases && !o->allow_unrelated_histories)
 			die(_("refusing to merge unrelated histories"));
 		merge_bases = reverse_commit_list(merge_bases);
diff --git a/builtin/merge.c b/builtin/merge.c
index 935c8a57dd..a0ba1f9815 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -1513,13 +1513,20 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 
 	if (!remoteheads)
 		; /* already up-to-date */
-	else if (!remoteheads->next)
-		common = repo_get_merge_bases(the_repository, head_commit,
-					      remoteheads->item);
-	else {
+	else if (!remoteheads->next) {
+		if (repo_get_merge_bases(the_repository, head_commit,
+					 remoteheads->item, &common) < 0) {
+			ret = 2;
+			goto done;
+		}
+	} else {
 		struct commit_list *list = remoteheads;
 		commit_list_insert(head_commit, &list);
-		common = get_octopus_merge_bases(list);
+		if (get_octopus_merge_bases(list, &common) < 0) {
+			free(list);
+			ret = 2;
+			goto done;
+		}
 		free(list);
 	}
 
@@ -1626,7 +1633,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		struct commit_list *j;
 
 		for (j = remoteheads; j; j = j->next) {
-			struct commit_list *common_one;
+			struct commit_list *common_one = NULL;
 			struct commit *common_item;
 
 			/*
@@ -1634,9 +1641,10 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 			 * merge_bases again, otherwise "git merge HEAD^
 			 * HEAD^^" would be missed.
 			 */
-			common_one = repo_get_merge_bases(the_repository,
-							  head_commit,
-							  j->item);
+			if (repo_get_merge_bases(the_repository, head_commit,
+						 j->item, &common_one) < 0)
+				exit(128);
+
 			common_item = common_one->item;
 			free_commit_list(common_one);
 			if (!oideq(&common_item->object.oid, &j->item->object.oid)) {
diff --git a/builtin/name-rev.c b/builtin/name-rev.c
index 2dd1807c4e..ad9930c831 100644
--- a/builtin/name-rev.c
+++ b/builtin/name-rev.c
@@ -15,6 +15,7 @@
 #include "commit-slab.h"
 #include "commit-graph.h"
 #include "wildmatch.h"
+#include "mem-pool.h"
 
 /*
  * One day.  See the 'name a rev shortly after epoch' test in t6120 when
@@ -155,30 +156,25 @@ static struct rev_name *create_or_update_name(struct commit *commit,
 	return name;
 }
 
-static char *get_parent_name(const struct rev_name *name, int parent_number)
+static char *get_parent_name(const struct rev_name *name, int parent_number,
+			     struct mem_pool *string_pool)
 {
-	struct strbuf sb = STRBUF_INIT;
 	size_t len;
 
 	strip_suffix(name->tip_name, "^0", &len);
 	if (name->generation > 0) {
-		strbuf_grow(&sb, len +
-			    1 + decimal_width(name->generation) +
-			    1 + decimal_width(parent_number));
-		strbuf_addf(&sb, "%.*s~%d^%d", (int)len, name->tip_name,
-			    name->generation, parent_number);
+		return mem_pool_strfmt(string_pool, "%.*s~%d^%d",
+				       (int)len, name->tip_name,
+				       name->generation, parent_number);
 	} else {
-		strbuf_grow(&sb, len +
-			    1 + decimal_width(parent_number));
-		strbuf_addf(&sb, "%.*s^%d", (int)len, name->tip_name,
-			    parent_number);
+		return mem_pool_strfmt(string_pool, "%.*s^%d",
+				       (int)len, name->tip_name, parent_number);
 	}
-	return strbuf_detach(&sb, NULL);
 }
 
 static void name_rev(struct commit *start_commit,
 		const char *tip_name, timestamp_t taggerdate,
-		int from_tag, int deref)
+		int from_tag, int deref, struct mem_pool *string_pool)
 {
 	struct prio_queue queue;
 	struct commit *commit;
@@ -195,9 +191,10 @@ static void name_rev(struct commit *start_commit,
 	if (!start_name)
 		return;
 	if (deref)
-		start_name->tip_name = xstrfmt("%s^0", tip_name);
+		start_name->tip_name = mem_pool_strfmt(string_pool, "%s^0",
+						       tip_name);
 	else
-		start_name->tip_name = xstrdup(tip_name);
+		start_name->tip_name = mem_pool_strdup(string_pool, tip_name);
 
 	memset(&queue, 0, sizeof(queue)); /* Use the prio_queue as LIFO */
 	prio_queue_put(&queue, start_commit);
@@ -235,7 +232,8 @@ static void name_rev(struct commit *start_commit,
 				if (parent_number > 1)
 					parent_name->tip_name =
 						get_parent_name(name,
-								parent_number);
+								parent_number,
+								string_pool);
 				else
 					parent_name->tip_name = name->tip_name;
 				ALLOC_GROW(parents_to_queue,
@@ -415,7 +413,7 @@ static int name_ref(const char *path, const struct object_id *oid,
 	return 0;
 }
 
-static void name_tips(void)
+static void name_tips(struct mem_pool *string_pool)
 {
 	int i;
 
@@ -428,7 +426,7 @@ static void name_tips(void)
 		struct tip_table_entry *e = &tip_table.table[i];
 		if (e->commit) {
 			name_rev(e->commit, e->refname, e->taggerdate,
-				 e->from_tag, e->deref);
+				 e->from_tag, e->deref, string_pool);
 		}
 	}
 }
@@ -561,6 +559,7 @@ static void name_rev_line(char *p, struct name_ref_data *data)
 
 int cmd_name_rev(int argc, const char **argv, const char *prefix)
 {
+	struct mem_pool string_pool;
 	struct object_array revs = OBJECT_ARRAY_INIT;
 	int all = 0, annotate_stdin = 0, transform_stdin = 0, allow_undefined = 1, always = 0, peel_tag = 0;
 	struct name_ref_data data = { 0, 0, STRING_LIST_INIT_NODUP, STRING_LIST_INIT_NODUP };
@@ -587,6 +586,7 @@ int cmd_name_rev(int argc, const char **argv, const char *prefix)
 		OPT_END(),
 	};
 
+	mem_pool_init(&string_pool, 0);
 	init_commit_rev_name(&rev_names);
 	git_config(git_default_config, NULL);
 	argc = parse_options(argc, argv, prefix, opts, name_rev_usage, 0);
@@ -648,7 +648,7 @@ int cmd_name_rev(int argc, const char **argv, const char *prefix)
 	adjust_cutoff_timestamp_for_slop();
 
 	for_each_ref(name_ref, &data);
-	name_tips();
+	name_tips(&string_pool);
 
 	if (annotate_stdin) {
 		struct strbuf sb = STRBUF_INIT;
@@ -676,6 +676,7 @@ int cmd_name_rev(int argc, const char **argv, const char *prefix)
 				  always, allow_undefined, data.name_only);
 	}
 
+	UNLEAK(string_pool);
 	UNLEAK(revs);
 	return 0;
 }
diff --git a/builtin/pull.c b/builtin/pull.c
index 73a68b75b0..72cbb76d52 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -815,7 +815,7 @@ static int get_octopus_merge_base(struct object_id *merge_base,
 		const struct object_id *merge_head,
 		const struct object_id *fork_point)
 {
-	struct commit_list *revs = NULL, *result;
+	struct commit_list *revs = NULL, *result = NULL;
 
 	commit_list_insert(lookup_commit_reference(the_repository, curr_head),
 			   &revs);
@@ -825,7 +825,8 @@ static int get_octopus_merge_base(struct object_id *merge_base,
 		commit_list_insert(lookup_commit_reference(the_repository, fork_point),
 				   &revs);
 
-	result = get_octopus_merge_bases(revs);
+	if (get_octopus_merge_bases(revs, &result) < 0)
+		exit(128);
 	free_commit_list(revs);
 	reduce_heads_replace(&result);
 
@@ -926,6 +927,8 @@ static int get_can_ff(struct object_id *orig_head,
 	merge_head = lookup_commit_reference(the_repository, orig_merge_head);
 	ret = repo_is_descendant_of(the_repository, merge_head, list);
 	free_commit_list(list);
+	if (ret < 0)
+		exit(128);
 	return ret;
 }
 
@@ -950,6 +953,8 @@ static int already_up_to_date(struct object_id *orig_head,
 		commit_list_insert(theirs, &list);
 		ok = repo_is_descendant_of(the_repository, ours, list);
 		free_commit_list(list);
+		if (ok < 0)
+			exit(128);
 		if (!ok)
 			return 0;
 	}
diff --git a/builtin/read-tree.c b/builtin/read-tree.c
index 20e7db1973..1ffd863cff 100644
--- a/builtin/read-tree.c
+++ b/builtin/read-tree.c
@@ -261,7 +261,8 @@ int cmd_read_tree(int argc, const char **argv, const char *cmd_prefix)
 	cache_tree_free(&the_index.cache_tree);
 	for (i = 0; i < nr_trees; i++) {
 		struct tree *tree = trees[i];
-		parse_tree(tree);
+		if (parse_tree(tree) < 0)
+			return 128;
 		init_tree_desc(t+i, tree->buffer, tree->size);
 	}
 	if (unpack_trees(nr_trees, t, &opts))
diff --git a/builtin/rebase.c b/builtin/rebase.c
index 5b086f651a..be787690bd 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -867,7 +867,8 @@ static int can_fast_forward(struct commit *onto, struct commit *upstream,
 	if (!upstream)
 		goto done;
 
-	merge_bases = repo_get_merge_bases(the_repository, upstream, head);
+	if (repo_get_merge_bases(the_repository, upstream, head, &merge_bases) < 0)
+		exit(128);
 	if (!merge_bases || merge_bases->next)
 		goto done;
 
@@ -886,8 +887,9 @@ static void fill_branch_base(struct rebase_options *options,
 {
 	struct commit_list *merge_bases = NULL;
 
-	merge_bases = repo_get_merge_bases(the_repository, options->onto,
-					   options->orig_head);
+	if (repo_get_merge_bases(the_repository, options->onto,
+				 options->orig_head, &merge_bases) < 0)
+		exit(128);
 	if (!merge_bases || merge_bases->next)
 		oidcpy(branch_base, null_oid());
 	else
@@ -1254,7 +1256,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		die(_("options '%s' and '%s' cannot be used together"), "--root", "--fork-point");
 
 	if (options.action != ACTION_NONE && !in_progress)
-		die(_("No rebase in progress?"));
+		die(_("no rebase in progress"));
 
 	if (options.action == ACTION_EDIT_TODO && !is_merge(&options))
 		die(_("The --edit-todo action can only be used during "
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index db65607485..56d8a77ed7 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1526,6 +1526,7 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 	    starts_with(name, "refs/heads/")) {
 		struct object *old_object, *new_object;
 		struct commit *old_commit, *new_commit;
+		int ret2;
 
 		old_object = parse_object(the_repository, old_oid);
 		new_object = parse_object(the_repository, new_oid);
@@ -1539,7 +1540,10 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 		}
 		old_commit = (struct commit *)old_object;
 		new_commit = (struct commit *)new_object;
-		if (!repo_in_merge_bases(the_repository, old_commit, new_commit)) {
+		ret2 = repo_in_merge_bases(the_repository, old_commit, new_commit);
+		if (ret2 < 0)
+			exit(128);
+		if (!ret2) {
 			rp_error("denying non-fast-forward %s"
 				 " (you should pull first)", name);
 			ret = "non-fast-forward";
diff --git a/builtin/reflog.c b/builtin/reflog.c
index 2c3369fca5..060eb3377e 100644
--- a/builtin/reflog.c
+++ b/builtin/reflog.c
@@ -7,11 +7,15 @@
 #include "wildmatch.h"
 #include "worktree.h"
 #include "reflog.h"
+#include "refs.h"
 #include "parse-options.h"
 
 #define BUILTIN_REFLOG_SHOW_USAGE \
 	N_("git reflog [show] [<log-options>] [<ref>]")
 
+#define BUILTIN_REFLOG_LIST_USAGE \
+	N_("git reflog list")
+
 #define BUILTIN_REFLOG_EXPIRE_USAGE \
 	N_("git reflog expire [--expire=<time>] [--expire-unreachable=<time>]\n" \
 	   "                  [--rewrite] [--updateref] [--stale-fix]\n" \
@@ -29,6 +33,11 @@ static const char *const reflog_show_usage[] = {
 	NULL,
 };
 
+static const char *const reflog_list_usage[] = {
+	BUILTIN_REFLOG_LIST_USAGE,
+	NULL,
+};
+
 static const char *const reflog_expire_usage[] = {
 	BUILTIN_REFLOG_EXPIRE_USAGE,
 	NULL
@@ -46,6 +55,7 @@ static const char *const reflog_exists_usage[] = {
 
 static const char *const reflog_usage[] = {
 	BUILTIN_REFLOG_SHOW_USAGE,
+	BUILTIN_REFLOG_LIST_USAGE,
 	BUILTIN_REFLOG_EXPIRE_USAGE,
 	BUILTIN_REFLOG_DELETE_USAGE,
 	BUILTIN_REFLOG_EXISTS_USAGE,
@@ -60,8 +70,7 @@ struct worktree_reflogs {
 	struct string_list reflogs;
 };
 
-static int collect_reflog(const char *ref, const struct object_id *oid UNUSED,
-			  int flags UNUSED, void *cb_data)
+static int collect_reflog(const char *ref, void *cb_data)
 {
 	struct worktree_reflogs *cb = cb_data;
 	struct worktree *worktree = cb->worktree;
@@ -238,6 +247,29 @@ static int cmd_reflog_show(int argc, const char **argv, const char *prefix)
 	return cmd_log_reflog(argc, argv, prefix);
 }
 
+static int show_reflog(const char *refname, void *cb_data UNUSED)
+{
+	printf("%s\n", refname);
+	return 0;
+}
+
+static int cmd_reflog_list(int argc, const char **argv, const char *prefix)
+{
+	struct option options[] = {
+		OPT_END()
+	};
+	struct ref_store *ref_store;
+
+	argc = parse_options(argc, argv, prefix, options, reflog_list_usage, 0);
+	if (argc)
+		return error(_("%s does not accept arguments: '%s'"),
+			     "list", argv[0]);
+
+	ref_store = get_main_ref_store(the_repository);
+
+	return refs_for_each_reflog(ref_store, show_reflog, NULL);
+}
+
 static int cmd_reflog_expire(int argc, const char **argv, const char *prefix)
 {
 	struct cmd_reflog_expire_cb cmd = { 0 };
@@ -417,6 +449,7 @@ int cmd_reflog(int argc, const char **argv, const char *prefix)
 	parse_opt_subcommand_fn *fn = NULL;
 	struct option options[] = {
 		OPT_SUBCOMMAND("show", &fn, cmd_reflog_show),
+		OPT_SUBCOMMAND("list", &fn, cmd_reflog_list),
 		OPT_SUBCOMMAND("expire", &fn, cmd_reflog_expire),
 		OPT_SUBCOMMAND("delete", &fn, cmd_reflog_delete),
 		OPT_SUBCOMMAND("exists", &fn, cmd_reflog_exists),
diff --git a/builtin/reset.c b/builtin/reset.c
index f0bf29a478..1d62ff6332 100644
--- a/builtin/reset.c
+++ b/builtin/reset.c
@@ -116,6 +116,10 @@ static int reset_index(const char *ref, const struct object_id *oid, int reset_t
 
 	if (reset_type == MIXED || reset_type == HARD) {
 		tree = parse_tree_indirect(oid);
+		if (!tree) {
+			error(_("unable to read tree (%s)"), oid_to_hex(oid));
+			goto out;
+		}
 		prime_cache_tree(the_repository, the_repository->index, tree);
 	}
 
diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index b3f4783858..ec455aa972 100644
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -545,6 +545,18 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix)
 	 *
 	 * Let "--missing" to conditionally set fetch_if_missing.
 	 */
+	/*
+	 * NEEDSWORK: These loops that attempt to find presence of
+	 * options without understanding that the options they are
+	 * skipping are broken (e.g., it would not know "--grep
+	 * --exclude-promisor-objects" is not triggering
+	 * "--exclude-promisor-objects" option).  We really need
+	 * setup_revisions() to have a mechanism to allow and disallow
+	 * some sets of options for different commands (like rev-list,
+	 * replay, etc). Such a mechanism should do an early parsing
+	 * of options and be able to manage the `--missing=...` and
+	 * `--exclude-promisor-objects` options below.
+	 */
 	for (i = 1; i < argc; i++) {
 		const char *arg = argv[i];
 		if (!strcmp(arg, "--exclude-promisor-objects")) {
@@ -753,8 +765,12 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix)
 
 	if (arg_print_omitted)
 		oidset_init(&omitted_objects, DEFAULT_OIDSET_SIZE);
-	if (arg_missing_action == MA_PRINT)
+	if (arg_missing_action == MA_PRINT) {
 		oidset_init(&missing_objects, DEFAULT_OIDSET_SIZE);
+		/* Add missing tips */
+		oidset_insert_from_set(&missing_objects, &revs.missing_commits);
+		oidset_clear(&revs.missing_commits);
+	}
 
 	traverse_commit_list_filtered(
 		&revs, show_commit, show_object, &info,
diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index d08987646a..181c703d4c 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -297,7 +297,7 @@ static int try_difference(const char *arg)
 		show_rev(NORMAL, &end_oid, end);
 		show_rev(symmetric ? NORMAL : REVERSED, &start_oid, start);
 		if (symmetric) {
-			struct commit_list *exclude;
+			struct commit_list *exclude = NULL;
 			struct commit *a, *b;
 			a = lookup_commit_reference(the_repository, &start_oid);
 			b = lookup_commit_reference(the_repository, &end_oid);
@@ -305,7 +305,8 @@ static int try_difference(const char *arg)
 				*dotdot = '.';
 				return 0;
 			}
-			exclude = repo_get_merge_bases(the_repository, a, b);
+			if (repo_get_merge_bases(the_repository, a, b, &exclude) < 0)
+				exit(128);
 			while (exclude) {
 				struct commit *commit = pop_commit(&exclude);
 				show_rev(REVERSED, &commit->object.oid, NULL);
diff --git a/builtin/tag.c b/builtin/tag.c
index 37473ac21f..19a7e06bf4 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -530,7 +530,8 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 			struct column_options copts;
 			memset(&copts, 0, sizeof(copts));
 			copts.padding = 2;
-			run_column_filter(colopts, &copts);
+			if (run_column_filter(colopts, &copts))
+				die(_("could not start 'git column'"));
 		}
 		filter.name_patterns = argv;
 		ret = list_tags(&filter, sorting, &format);
diff --git a/builtin/upload-pack.c b/builtin/upload-pack.c
index 9b021ef026..15afb97260 100644
--- a/builtin/upload-pack.c
+++ b/builtin/upload-pack.c
@@ -8,6 +8,7 @@
 #include "replace-object.h"
 #include "upload-pack.h"
 #include "serve.h"
+#include "commit.h"
 
 static const char * const upload_pack_usage[] = {
 	N_("git-upload-pack [--[no-]strict] [--timeout=<n>] [--stateless-rpc]\n"
@@ -37,6 +38,7 @@ int cmd_upload_pack(int argc, const char **argv, const char *prefix)
 
 	packet_trace_identity("upload-pack");
 	disable_replace_refs();
+	save_commit_buffer = 0;
 
 	argc = parse_options(argc, argv, prefix, options, upload_pack_usage, 0);
 
diff --git a/cache-tree.c b/cache-tree.c
index 64678fe199..80ca832477 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -778,8 +778,8 @@ static void prime_cache_tree_rec(struct repository *r,
 			struct cache_tree_sub *sub;
 			struct tree *subtree = lookup_tree(r, &entry.oid);
 
-			if (!subtree->object.parsed)
-				parse_tree(subtree);
+			if (parse_tree(subtree) < 0)
+				exit(128);
 			sub = cache_tree_sub(it, entry.path);
 			sub->cache_tree = cache_tree();
 
diff --git a/commit-reach.c b/commit-reach.c
index ecc913fc99..8f9b008f87 100644
--- a/commit-reach.c
+++ b/commit-reach.c
@@ -49,13 +49,14 @@ static int queue_has_nonstale(struct prio_queue *queue)
 }
 
 /* all input commits in one and twos[] must have been parsed! */
-static struct commit_list *paint_down_to_common(struct repository *r,
-						struct commit *one, int n,
-						struct commit **twos,
-						timestamp_t min_generation)
+static int paint_down_to_common(struct repository *r,
+				struct commit *one, int n,
+				struct commit **twos,
+				timestamp_t min_generation,
+				int ignore_missing_commits,
+				struct commit_list **result)
 {
 	struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
-	struct commit_list *result = NULL;
 	int i;
 	timestamp_t last_gen = GENERATION_NUMBER_INFINITY;
 
@@ -64,8 +65,8 @@ static struct commit_list *paint_down_to_common(struct repository *r,
 
 	one->object.flags |= PARENT1;
 	if (!n) {
-		commit_list_append(one, &result);
-		return result;
+		commit_list_append(one, result);
+		return 0;
 	}
 	prio_queue_put(&queue, one);
 
@@ -93,7 +94,7 @@ static struct commit_list *paint_down_to_common(struct repository *r,
 		if (flags == (PARENT1 | PARENT2)) {
 			if (!(commit->object.flags & RESULT)) {
 				commit->object.flags |= RESULT;
-				commit_list_insert_by_date(commit, &result);
+				commit_list_insert_by_date(commit, result);
 			}
 			/* Mark parents of a found merge stale */
 			flags |= STALE;
@@ -104,67 +105,97 @@ static struct commit_list *paint_down_to_common(struct repository *r,
 			parents = parents->next;
 			if ((p->object.flags & flags) == flags)
 				continue;
-			if (repo_parse_commit(r, p))
-				return NULL;
+			if (repo_parse_commit(r, p)) {
+				clear_prio_queue(&queue);
+				free_commit_list(*result);
+				*result = NULL;
+				/*
+				 * At this stage, we know that the commit is
+				 * missing: `repo_parse_commit()` uses
+				 * `OBJECT_INFO_DIE_IF_CORRUPT` and therefore
+				 * corrupt commits would already have been
+				 * dispatched with a `die()`.
+				 */
+				if (ignore_missing_commits)
+					return 0;
+				return error(_("could not parse commit %s"),
+					     oid_to_hex(&p->object.oid));
+			}
 			p->object.flags |= flags;
 			prio_queue_put(&queue, p);
 		}
 	}
 
 	clear_prio_queue(&queue);
-	return result;
+	return 0;
 }
 
-static struct commit_list *merge_bases_many(struct repository *r,
-					    struct commit *one, int n,
-					    struct commit **twos)
+static int merge_bases_many(struct repository *r,
+			    struct commit *one, int n,
+			    struct commit **twos,
+			    struct commit_list **result)
 {
 	struct commit_list *list = NULL;
-	struct commit_list *result = NULL;
 	int i;
 
 	for (i = 0; i < n; i++) {
-		if (one == twos[i])
+		if (one == twos[i]) {
 			/*
 			 * We do not mark this even with RESULT so we do not
 			 * have to clean it up.
 			 */
-			return commit_list_insert(one, &result);
+			*result = commit_list_insert(one, result);
+			return 0;
+		}
 	}
 
+	if (!one)
+		return 0;
 	if (repo_parse_commit(r, one))
-		return NULL;
+		return error(_("could not parse commit %s"),
+			     oid_to_hex(&one->object.oid));
 	for (i = 0; i < n; i++) {
+		if (!twos[i])
+			return 0;
 		if (repo_parse_commit(r, twos[i]))
-			return NULL;
+			return error(_("could not parse commit %s"),
+				     oid_to_hex(&twos[i]->object.oid));
 	}
 
-	list = paint_down_to_common(r, one, n, twos, 0);
+	if (paint_down_to_common(r, one, n, twos, 0, 0, &list)) {
+		free_commit_list(list);
+		return -1;
+	}
 
 	while (list) {
 		struct commit *commit = pop_commit(&list);
 		if (!(commit->object.flags & STALE))
-			commit_list_insert_by_date(commit, &result);
+			commit_list_insert_by_date(commit, result);
 	}
-	return result;
+	return 0;
 }
 
-struct commit_list *get_octopus_merge_bases(struct commit_list *in)
+int get_octopus_merge_bases(struct commit_list *in, struct commit_list **result)
 {
-	struct commit_list *i, *j, *k, *ret = NULL;
+	struct commit_list *i, *j, *k;
 
 	if (!in)
-		return ret;
+		return 0;
 
-	commit_list_insert(in->item, &ret);
+	commit_list_insert(in->item, result);
 
 	for (i = in->next; i; i = i->next) {
 		struct commit_list *new_commits = NULL, *end = NULL;
 
-		for (j = ret; j; j = j->next) {
-			struct commit_list *bases;
-			bases = repo_get_merge_bases(the_repository, i->item,
-						     j->item);
+		for (j = *result; j; j = j->next) {
+			struct commit_list *bases = NULL;
+			if (repo_get_merge_bases(the_repository, i->item,
+						 j->item, &bases) < 0) {
+				free_commit_list(bases);
+				free_commit_list(*result);
+				*result = NULL;
+				return -1;
+			}
 			if (!new_commits)
 				new_commits = bases;
 			else
@@ -172,10 +203,10 @@ struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 			for (k = bases; k; k = k->next)
 				end = k;
 		}
-		free_commit_list(ret);
-		ret = new_commits;
+		free_commit_list(*result);
+		*result = new_commits;
 	}
-	return ret;
+	return 0;
 }
 
 static int remove_redundant_no_gen(struct repository *r,
@@ -193,7 +224,7 @@ static int remove_redundant_no_gen(struct repository *r,
 	for (i = 0; i < cnt; i++)
 		repo_parse_commit(r, array[i]);
 	for (i = 0; i < cnt; i++) {
-		struct commit_list *common;
+		struct commit_list *common = NULL;
 		timestamp_t min_generation = commit_graph_generation(array[i]);
 
 		if (redundant[i])
@@ -209,8 +240,16 @@ static int remove_redundant_no_gen(struct repository *r,
 			if (curr_generation < min_generation)
 				min_generation = curr_generation;
 		}
-		common = paint_down_to_common(r, array[i], filled,
-					      work, min_generation);
+		if (paint_down_to_common(r, array[i], filled,
+					 work, min_generation, 0, &common)) {
+			clear_commit_marks(array[i], all_flags);
+			clear_commit_marks_many(filled, work, all_flags);
+			free_commit_list(common);
+			free(work);
+			free(redundant);
+			free(filled_index);
+			return -1;
+		}
 		if (array[i]->object.flags & PARENT2)
 			redundant[i] = 1;
 		for (j = 0; j < filled; j++)
@@ -375,69 +414,77 @@ static int remove_redundant(struct repository *r, struct commit **array, int cnt
 	return remove_redundant_no_gen(r, array, cnt);
 }
 
-static struct commit_list *get_merge_bases_many_0(struct repository *r,
-						  struct commit *one,
-						  int n,
-						  struct commit **twos,
-						  int cleanup)
+static int get_merge_bases_many_0(struct repository *r,
+				  struct commit *one,
+				  int n,
+				  struct commit **twos,
+				  int cleanup,
+				  struct commit_list **result)
 {
 	struct commit_list *list;
 	struct commit **rslt;
-	struct commit_list *result;
 	int cnt, i;
 
-	result = merge_bases_many(r, one, n, twos);
+	if (merge_bases_many(r, one, n, twos, result) < 0)
+		return -1;
 	for (i = 0; i < n; i++) {
 		if (one == twos[i])
-			return result;
+			return 0;
 	}
-	if (!result || !result->next) {
+	if (!*result || !(*result)->next) {
 		if (cleanup) {
 			clear_commit_marks(one, all_flags);
 			clear_commit_marks_many(n, twos, all_flags);
 		}
-		return result;
+		return 0;
 	}
 
 	/* There are more than one */
-	cnt = commit_list_count(result);
+	cnt = commit_list_count(*result);
 	CALLOC_ARRAY(rslt, cnt);
-	for (list = result, i = 0; list; list = list->next)
+	for (list = *result, i = 0; list; list = list->next)
 		rslt[i++] = list->item;
-	free_commit_list(result);
+	free_commit_list(*result);
+	*result = NULL;
 
 	clear_commit_marks(one, all_flags);
 	clear_commit_marks_many(n, twos, all_flags);
 
 	cnt = remove_redundant(r, rslt, cnt);
-	result = NULL;
+	if (cnt < 0) {
+		free(rslt);
+		return -1;
+	}
 	for (i = 0; i < cnt; i++)
-		commit_list_insert_by_date(rslt[i], &result);
+		commit_list_insert_by_date(rslt[i], result);
 	free(rslt);
-	return result;
+	return 0;
 }
 
-struct commit_list *repo_get_merge_bases_many(struct repository *r,
-					      struct commit *one,
-					      int n,
-					      struct commit **twos)
+int repo_get_merge_bases_many(struct repository *r,
+			      struct commit *one,
+			      int n,
+			      struct commit **twos,
+			      struct commit_list **result)
 {
-	return get_merge_bases_many_0(r, one, n, twos, 1);
+	return get_merge_bases_many_0(r, one, n, twos, 1, result);
 }
 
-struct commit_list *repo_get_merge_bases_many_dirty(struct repository *r,
-						    struct commit *one,
-						    int n,
-						    struct commit **twos)
+int repo_get_merge_bases_many_dirty(struct repository *r,
+				    struct commit *one,
+				    int n,
+				    struct commit **twos,
+				    struct commit_list **result)
 {
-	return get_merge_bases_many_0(r, one, n, twos, 0);
+	return get_merge_bases_many_0(r, one, n, twos, 0, result);
 }
 
-struct commit_list *repo_get_merge_bases(struct repository *r,
-					 struct commit *one,
-					 struct commit *two)
+int repo_get_merge_bases(struct repository *r,
+			 struct commit *one,
+			 struct commit *two,
+			 struct commit_list **result)
 {
-	return get_merge_bases_many_0(r, one, 1, &two, 1);
+	return get_merge_bases_many_0(r, one, 1, &two, 1, result);
 }
 
 /*
@@ -460,11 +507,13 @@ int repo_is_descendant_of(struct repository *r,
 	} else {
 		while (with_commit) {
 			struct commit *other;
+			int ret;
 
 			other = with_commit->item;
 			with_commit = with_commit->next;
-			if (repo_in_merge_bases_many(r, other, 1, &commit))
-				return 1;
+			ret = repo_in_merge_bases_many(r, other, 1, &commit, 0);
+			if (ret)
+				return ret;
 		}
 		return 0;
 	}
@@ -474,17 +523,18 @@ int repo_is_descendant_of(struct repository *r,
  * Is "commit" an ancestor of one of the "references"?
  */
 int repo_in_merge_bases_many(struct repository *r, struct commit *commit,
-			     int nr_reference, struct commit **reference)
+			     int nr_reference, struct commit **reference,
+			     int ignore_missing_commits)
 {
-	struct commit_list *bases;
+	struct commit_list *bases = NULL;
 	int ret = 0, i;
 	timestamp_t generation, max_generation = GENERATION_NUMBER_ZERO;
 
 	if (repo_parse_commit(r, commit))
-		return ret;
+		return ignore_missing_commits ? 0 : -1;
 	for (i = 0; i < nr_reference; i++) {
 		if (repo_parse_commit(r, reference[i]))
-			return ret;
+			return ignore_missing_commits ? 0 : -1;
 
 		generation = commit_graph_generation(reference[i]);
 		if (generation > max_generation)
@@ -495,10 +545,11 @@ int repo_in_merge_bases_many(struct repository *r, struct commit *commit,
 	if (generation > max_generation)
 		return ret;
 
-	bases = paint_down_to_common(r, commit,
-				     nr_reference, reference,
-				     generation);
-	if (commit->object.flags & PARENT2)
+	if (paint_down_to_common(r, commit,
+				 nr_reference, reference,
+				 generation, ignore_missing_commits, &bases))
+		ret = -1;
+	else if (commit->object.flags & PARENT2)
 		ret = 1;
 	clear_commit_marks(commit, all_flags);
 	clear_commit_marks_many(nr_reference, reference, all_flags);
@@ -551,6 +602,10 @@ struct commit_list *reduce_heads(struct commit_list *heads)
 		}
 	}
 	num_head = remove_redundant(the_repository, array, num_head);
+	if (num_head < 0) {
+		free(array);
+		return NULL;
+	}
 	for (i = 0; i < num_head; i++)
 		tail = &commit_list_insert(array[i], tail)->next;
 	free(array);
@@ -593,6 +648,8 @@ int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
 	commit_list_insert(old_commit, &old_commit_list);
 	ret = repo_is_descendant_of(the_repository,
 				    new_commit, old_commit_list);
+	if (ret < 0)
+		exit(128);
 	free_commit_list(old_commit_list);
 	return ret;
 }
diff --git a/commit-reach.h b/commit-reach.h
index 35c4da4948..bf63cc468f 100644
--- a/commit-reach.h
+++ b/commit-reach.h
@@ -9,18 +9,21 @@ struct ref_filter;
 struct object_id;
 struct object_array;
 
-struct commit_list *repo_get_merge_bases(struct repository *r,
-					 struct commit *rev1,
-					 struct commit *rev2);
-struct commit_list *repo_get_merge_bases_many(struct repository *r,
-					      struct commit *one, int n,
-					      struct commit **twos);
+int repo_get_merge_bases(struct repository *r,
+			 struct commit *rev1,
+			 struct commit *rev2,
+			 struct commit_list **result);
+int repo_get_merge_bases_many(struct repository *r,
+			      struct commit *one, int n,
+			      struct commit **twos,
+			      struct commit_list **result);
 /* To be used only when object flags after this call no longer matter */
-struct commit_list *repo_get_merge_bases_many_dirty(struct repository *r,
-						    struct commit *one, int n,
-						    struct commit **twos);
+int repo_get_merge_bases_many_dirty(struct repository *r,
+				    struct commit *one, int n,
+				    struct commit **twos,
+				    struct commit_list **result);
 
-struct commit_list *get_octopus_merge_bases(struct commit_list *in);
+int get_octopus_merge_bases(struct commit_list *in, struct commit_list **result);
 
 int repo_is_descendant_of(struct repository *r,
 			  struct commit *commit,
@@ -30,7 +33,8 @@ int repo_in_merge_bases(struct repository *r,
 			struct commit *reference);
 int repo_in_merge_bases_many(struct repository *r,
 			     struct commit *commit,
-			     int nr_reference, struct commit **reference);
+			     int nr_reference, struct commit **reference,
+			     int ignore_missing_commits);
 
 /*
  * Takes a list of commits and returns a new list where those
diff --git a/commit.c b/commit.c
index ef679a0b93..467be9f7f9 100644
--- a/commit.c
+++ b/commit.c
@@ -1052,7 +1052,7 @@ struct commit *get_fork_point(const char *refname, struct commit *commit)
 {
 	struct object_id oid;
 	struct rev_collect revs;
-	struct commit_list *bases;
+	struct commit_list *bases = NULL;
 	int i;
 	struct commit *ret = NULL;
 	char *full_refname;
@@ -1077,8 +1077,9 @@ struct commit *get_fork_point(const char *refname, struct commit *commit)
 	for (i = 0; i < revs.nr; i++)
 		revs.commit[i]->object.flags &= ~TMP_MARK;
 
-	bases = repo_get_merge_bases_many(the_repository, commit, revs.nr,
-					  revs.commit);
+	if (repo_get_merge_bases_many(the_repository, commit, revs.nr,
+				      revs.commit, &bases) < 0)
+		exit(128);
 
 	/*
 	 * There should be one and only one merge base, when we found
diff --git a/compat/compiler.h b/compat/compiler.h
index 10dbb65937..e9ad9db84f 100644
--- a/compat/compiler.h
+++ b/compat/compiler.h
@@ -1,7 +1,6 @@
 #ifndef COMPILER_H
 #define COMPILER_H
 
-#include "git-compat-util.h"
 #include "strbuf.h"
 
 #ifdef __GLIBC__
diff --git a/compat/disk.h b/compat/disk.h
index 6c979c27d8..23bc1bef86 100644
--- a/compat/disk.h
+++ b/compat/disk.h
@@ -1,7 +1,6 @@
 #ifndef COMPAT_DISK_H
 #define COMPAT_DISK_H
 
-#include "git-compat-util.h"
 #include "abspath.h"
 #include "gettext.h"
 
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 444b3efa63..fcf1afd75d 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -2673,7 +2673,8 @@ __git_compute_first_level_config_vars_for_section ()
 	__git_compute_config_vars
 	local this_section="__git_first_level_config_vars_for_section_${section}"
 	test -n "${!this_section}" ||
-	printf -v "__git_first_level_config_vars_for_section_${section}" %s "$(echo "$__git_config_vars" | grep -E "^${section}\.[a-z]" | awk -F. '{print $2}')"
+	printf -v "__git_first_level_config_vars_for_section_${section}" %s \
+		"$(echo "$__git_config_vars" | awk -F. "/^${section}\.[a-z]/ { print \$2 }")"
 }
 
 __git_compute_second_level_config_vars_for_section ()
@@ -2682,7 +2683,8 @@ __git_compute_second_level_config_vars_for_section ()
 	__git_compute_config_vars_all
 	local this_section="__git_second_level_config_vars_for_section_${section}"
 	test -n "${!this_section}" ||
-	printf -v "__git_second_level_config_vars_for_section_${section}" %s "$(echo "$__git_config_vars_all" | grep -E "^${section}\.<" | awk -F. '{print $3}')"
+	printf -v "__git_second_level_config_vars_for_section_${section}" %s \
+		"$(echo "$__git_config_vars_all" | awk -F. "/^${section}\.</ { print \$3 }")"
 }
 
 __git_config_sections=
diff --git a/contrib/credential/libsecret/git-credential-libsecret.c b/contrib/credential/libsecret/git-credential-libsecret.c
index 215a81d8ba..90034d0cf1 100644
--- a/contrib/credential/libsecret/git-credential-libsecret.c
+++ b/contrib/credential/libsecret/git-credential-libsecret.c
@@ -164,6 +164,9 @@ static int keyring_get(struct credential *c)
 			if (g_strv_length(parts) >= 1) {
 				g_free(c->password);
 				c->password = g_strdup(parts[0]);
+			} else {
+				g_free(c->password);
+				c->password = g_strdup("");
 			}
 			for (int i = 1; i < g_strv_length(parts); i++) {
 				if (g_str_has_prefix(parts[i], "password_expiry_utc=")) {
diff --git a/diff-lib.c b/diff-lib.c
index 6c8df04273..5e8717c774 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -570,7 +570,7 @@ void diff_get_merge_base(const struct rev_info *revs, struct object_id *mb)
 {
 	int i;
 	struct commit *mb_child[2] = {0};
-	struct commit_list *merge_bases;
+	struct commit_list *merge_bases = NULL;
 
 	for (i = 0; i < revs->pending.nr; i++) {
 		struct object *obj = revs->pending.objects[i].item;
@@ -597,7 +597,8 @@ void diff_get_merge_base(const struct rev_info *revs, struct object_id *mb)
 		mb_child[1] = lookup_commit_reference(the_repository, &oid);
 	}
 
-	merge_bases = repo_get_merge_bases(the_repository, mb_child[0], mb_child[1]);
+	if (repo_get_merge_bases(the_repository, mb_child[0], mb_child[1], &merge_bases) < 0)
+		exit(128);
 	if (!merge_bases)
 		die(_("no merge base found"));
 	if (merge_bases->next)
diff --git a/dir-iterator.c b/dir-iterator.c
index 278b04243a..de619846f2 100644
--- a/dir-iterator.c
+++ b/dir-iterator.c
@@ -2,10 +2,19 @@
 #include "dir.h"
 #include "iterator.h"
 #include "dir-iterator.h"
+#include "string-list.h"
 
 struct dir_iterator_level {
 	DIR *dir;
 
+	/*
+	 * The directory entries of the current level. This list will only be
+	 * populated when the iterator is ordered. In that case, `dir` will be
+	 * set to `NULL`.
+	 */
+	struct string_list entries;
+	size_t entries_idx;
+
 	/*
 	 * The length of the directory part of path at this level
 	 * (including a trailing '/'):
@@ -43,6 +52,31 @@ struct dir_iterator_int {
 	unsigned int flags;
 };
 
+static int next_directory_entry(DIR *dir, const char *path,
+				struct dirent **out)
+{
+	struct dirent *de;
+
+repeat:
+	errno = 0;
+	de = readdir(dir);
+	if (!de) {
+		if (errno) {
+			warning_errno("error reading directory '%s'",
+				      path);
+			return -1;
+		}
+
+		return 1;
+	}
+
+	if (is_dot_or_dotdot(de->d_name))
+		goto repeat;
+
+	*out = de;
+	return 0;
+}
+
 /*
  * Push a level in the iter stack and initialize it with information from
  * the directory pointed by iter->base->path. It is assumed that this
@@ -72,6 +106,35 @@ static int push_level(struct dir_iterator_int *iter)
 		return -1;
 	}
 
+	string_list_init_dup(&level->entries);
+	level->entries_idx = 0;
+
+	/*
+	 * When the iterator is sorted we read and sort all directory entries
+	 * directly.
+	 */
+	if (iter->flags & DIR_ITERATOR_SORTED) {
+		struct dirent *de;
+
+		while (1) {
+			int ret = next_directory_entry(level->dir, iter->base.path.buf, &de);
+			if (ret < 0) {
+				if (errno != ENOENT &&
+				    iter->flags & DIR_ITERATOR_PEDANTIC)
+					return -1;
+				continue;
+			} else if (ret > 0) {
+				break;
+			}
+
+			string_list_append(&level->entries, de->d_name);
+		}
+		string_list_sort(&level->entries);
+
+		closedir(level->dir);
+		level->dir = NULL;
+	}
+
 	return 0;
 }
 
@@ -88,21 +151,22 @@ static int pop_level(struct dir_iterator_int *iter)
 		warning_errno("error closing directory '%s'",
 			      iter->base.path.buf);
 	level->dir = NULL;
+	string_list_clear(&level->entries, 0);
 
 	return --iter->levels_nr;
 }
 
 /*
  * Populate iter->base with the necessary information on the next iteration
- * entry, represented by the given dirent de. Return 0 on success and -1
+ * entry, represented by the given name. Return 0 on success and -1
  * otherwise, setting errno accordingly.
  */
 static int prepare_next_entry_data(struct dir_iterator_int *iter,
-				   struct dirent *de)
+				   const char *name)
 {
 	int err, saved_errno;
 
-	strbuf_addstr(&iter->base.path, de->d_name);
+	strbuf_addstr(&iter->base.path, name);
 	/*
 	 * We have to reset these because the path strbuf might have
 	 * been realloc()ed at the previous strbuf_addstr().
@@ -139,27 +203,34 @@ int dir_iterator_advance(struct dir_iterator *dir_iterator)
 		struct dirent *de;
 		struct dir_iterator_level *level =
 			&iter->levels[iter->levels_nr - 1];
+		const char *name;
 
 		strbuf_setlen(&iter->base.path, level->prefix_len);
-		errno = 0;
-		de = readdir(level->dir);
 
-		if (!de) {
-			if (errno) {
-				warning_errno("error reading directory '%s'",
-					      iter->base.path.buf);
+		if (level->dir) {
+			int ret = next_directory_entry(level->dir, iter->base.path.buf, &de);
+			if (ret < 0) {
 				if (iter->flags & DIR_ITERATOR_PEDANTIC)
 					goto error_out;
-			} else if (pop_level(iter) == 0) {
-				return dir_iterator_abort(dir_iterator);
+				continue;
+			} else if (ret > 0) {
+				if (pop_level(iter) == 0)
+					return dir_iterator_abort(dir_iterator);
+				continue;
 			}
-			continue;
-		}
 
-		if (is_dot_or_dotdot(de->d_name))
-			continue;
+			name = de->d_name;
+		} else {
+			if (level->entries_idx >= level->entries.nr) {
+				if (pop_level(iter) == 0)
+					return dir_iterator_abort(dir_iterator);
+				continue;
+			}
 
-		if (prepare_next_entry_data(iter, de)) {
+			name = level->entries.items[level->entries_idx++].string;
+		}
+
+		if (prepare_next_entry_data(iter, name)) {
 			if (errno != ENOENT && iter->flags & DIR_ITERATOR_PEDANTIC)
 				goto error_out;
 			continue;
@@ -188,6 +259,8 @@ int dir_iterator_abort(struct dir_iterator *dir_iterator)
 			warning_errno("error closing directory '%s'",
 				      iter->base.path.buf);
 		}
+
+		string_list_clear(&level->entries, 0);
 	}
 
 	free(iter->levels);
diff --git a/dir-iterator.h b/dir-iterator.h
index 479e1ec784..6d438809b6 100644
--- a/dir-iterator.h
+++ b/dir-iterator.h
@@ -54,8 +54,11 @@
  *   and ITER_ERROR is returned immediately. In both cases, a meaningful
  *   warning is emitted. Note: ENOENT errors are always ignored so that
  *   the API users may remove files during iteration.
+ *
+ * - DIR_ITERATOR_SORTED: sort directory entries alphabetically.
  */
 #define DIR_ITERATOR_PEDANTIC (1 << 0)
+#define DIR_ITERATOR_SORTED   (1 << 1)
 
 struct dir_iterator {
 	/* The current path: */
diff --git a/environment.c b/environment.c
index 90632a39bc..60706ea398 100644
--- a/environment.c
+++ b/environment.c
@@ -207,6 +207,9 @@ void setup_git_env(const char *git_dir)
 	shallow_file = getenv(GIT_SHALLOW_FILE_ENVIRONMENT);
 	if (shallow_file)
 		set_alternate_shallow_file(the_repository, shallow_file, 0);
+
+	if (git_env_bool(NO_LAZY_FETCH_ENVIRONMENT, 0))
+		fetch_if_missing = 0;
 }
 
 int is_bare_repository(void)
diff --git a/environment.h b/environment.h
index e5351c9dd9..5cec19cecc 100644
--- a/environment.h
+++ b/environment.h
@@ -36,6 +36,7 @@ const char *getenv_safe(struct strvec *argv, const char *name);
 #define CEILING_DIRECTORIES_ENVIRONMENT "GIT_CEILING_DIRECTORIES"
 #define NO_REPLACE_OBJECTS_ENVIRONMENT "GIT_NO_REPLACE_OBJECTS"
 #define GIT_REPLACE_REF_BASE_ENVIRONMENT "GIT_REPLACE_REF_BASE"
+#define NO_LAZY_FETCH_ENVIRONMENT "GIT_NO_LAZY_FETCH"
 #define GITATTRIBUTES_FILE ".gitattributes"
 #define INFOATTRIBUTES_FILE "info/attributes"
 #define ATTRIBUTE_MACRO_PREFIX "[attr]"
diff --git a/git-difftool--helper.sh b/git-difftool--helper.sh
index e4e820e680..dd0c9a5b7f 100755
--- a/git-difftool--helper.sh
+++ b/git-difftool--helper.sh
@@ -91,6 +91,19 @@ then
 	# ignore the error from the above --- run_merge_tool
 	# will diagnose unusable tool by itself
 	run_merge_tool "$merge_tool" false
+
+	status=$?
+	if test $status -ge 126
+	then
+		# Command not found (127), not executable (126) or
+		# exited via a signal (>= 128).
+		exit $status
+	fi
+
+	if test "$GIT_DIFFTOOL_TRUST_EXIT_CODE" = true
+	then
+		exit $status
+	fi
 else
 	# Launch the merge tool on each path provided by 'git diff'
 	while test $# -gt 6
diff --git a/git.c b/git.c
index 7068a184b0..5265f920f1 100644
--- a/git.c
+++ b/git.c
@@ -4,6 +4,7 @@
 #include "exec-cmd.h"
 #include "gettext.h"
 #include "help.h"
+#include "object-file.h"
 #include "pager.h"
 #include "read-cache-ll.h"
 #include "run-command.h"
@@ -186,6 +187,11 @@ static int handle_options(const char ***argv, int *argc, int *envchanged)
 			use_pager = 0;
 			if (envchanged)
 				*envchanged = 1;
+		} else if (!strcmp(cmd, "--no-lazy-fetch")) {
+			fetch_if_missing = 0;
+			setenv(NO_LAZY_FETCH_ENVIRONMENT, "1", 1);
+			if (envchanged)
+				*envchanged = 1;
 		} else if (!strcmp(cmd, "--no-replace-objects")) {
 			disable_replace_refs();
 			setenv(NO_REPLACE_OBJECTS_ENVIRONMENT, "1", 1);
diff --git a/http-push.c b/http-push.c
index 12d1113741..33db41bfac 100644
--- a/http-push.c
+++ b/http-push.c
@@ -1575,8 +1575,11 @@ static int verify_merge_base(struct object_id *head_oid, struct ref *remote)
 	struct commit *head = lookup_commit_or_die(head_oid, "HEAD");
 	struct commit *branch = lookup_commit_or_die(&remote->old_oid,
 						     remote->name);
+	int ret = repo_in_merge_bases(the_repository, branch, head);
 
-	return repo_in_merge_bases(the_repository, branch, head);
+	if (ret < 0)
+		exit(128);
+	return ret;
 }
 
 static int delete_remote_branch(const char *pattern, int force)
diff --git a/list-objects-filter.c b/list-objects-filter.c
index da287cc8e0..4346f8da45 100644
--- a/list-objects-filter.c
+++ b/list-objects-filter.c
@@ -711,15 +711,6 @@ static void filter_combine__free(void *filter_data)
 	free(d);
 }
 
-static void add_all(struct oidset *dest, struct oidset *src) {
-	struct oidset_iter iter;
-	struct object_id *src_oid;
-
-	oidset_iter_init(src, &iter);
-	while ((src_oid = oidset_iter_next(&iter)) != NULL)
-		oidset_insert(dest, src_oid);
-}
-
 static void filter_combine__finalize_omits(
 	struct oidset *omits,
 	void *filter_data)
@@ -728,7 +719,7 @@ static void filter_combine__finalize_omits(
 	size_t sub;
 
 	for (sub = 0; sub < d->nr; sub++) {
-		add_all(omits, &d->sub[sub].omits);
+		oidset_insert_from_set(omits, &d->sub[sub].omits);
 		oidset_clear(&d->sub[sub].omits);
 	}
 }
diff --git a/log-tree.c b/log-tree.c
index 337b9334cd..e5438b029d 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -1011,7 +1011,7 @@ static int do_remerge_diff(struct rev_info *opt,
 			   struct object_id *oid)
 {
 	struct merge_options o;
-	struct commit_list *bases;
+	struct commit_list *bases = NULL;
 	struct merge_result res = {0};
 	struct pretty_print_context ctx = {0};
 	struct commit *parent1 = parents->item;
@@ -1036,7 +1036,8 @@ static int do_remerge_diff(struct rev_info *opt,
 	/* Parse the relevant commits and get the merge bases */
 	parse_commit_or_die(parent1);
 	parse_commit_or_die(parent2);
-	bases = repo_get_merge_bases(the_repository, parent1, parent2);
+	if (repo_get_merge_bases(the_repository, parent1, parent2, &bases) < 0)
+		exit(128);
 
 	/* Re-merge the parents */
 	merge_incore_recursive(&o, bases, parent1, parent2, &res);
diff --git a/mem-pool.c b/mem-pool.c
index c7d6256020..2078c22b09 100644
--- a/mem-pool.c
+++ b/mem-pool.c
@@ -107,6 +107,45 @@ void *mem_pool_alloc(struct mem_pool *pool, size_t len)
 	return r;
 }
 
+static char *mem_pool_strvfmt(struct mem_pool *pool, const char *fmt,
+			      va_list ap)
+{
+	struct mp_block *block = pool->mp_block;
+	char *next_free = block ? block->next_free : NULL;
+	size_t available = block ? block->end - block->next_free : 0;
+	va_list cp;
+	int len, len2;
+	char *ret;
+
+	va_copy(cp, ap);
+	len = vsnprintf(next_free, available, fmt, cp);
+	va_end(cp);
+	if (len < 0)
+		BUG("your vsnprintf is broken (returned %d)", len);
+
+	ret = mem_pool_alloc(pool, len + 1);  /* 1 for NUL */
+
+	/* Shortcut; relies on mem_pool_alloc() not touching buffer contents. */
+	if (ret == next_free)
+		return ret;
+
+	len2 = vsnprintf(ret, len + 1, fmt, ap);
+	if (len2 != len)
+		BUG("your vsnprintf is broken (returns inconsistent lengths)");
+	return ret;
+}
+
+char *mem_pool_strfmt(struct mem_pool *pool, const char *fmt, ...)
+{
+	va_list ap;
+	char *ret;
+
+	va_start(ap, fmt);
+	ret = mem_pool_strvfmt(pool, fmt, ap);
+	va_end(ap);
+	return ret;
+}
+
 void *mem_pool_calloc(struct mem_pool *pool, size_t count, size_t size)
 {
 	size_t len = st_mult(count, size);
diff --git a/mem-pool.h b/mem-pool.h
index fe7507f022..d1c66413ec 100644
--- a/mem-pool.h
+++ b/mem-pool.h
@@ -47,6 +47,11 @@ void *mem_pool_calloc(struct mem_pool *pool, size_t count, size_t size);
 char *mem_pool_strdup(struct mem_pool *pool, const char *str);
 char *mem_pool_strndup(struct mem_pool *pool, const char *str, size_t len);
 
+/*
+ * Allocate memory from the memory pool and format a string into it.
+ */
+char *mem_pool_strfmt(struct mem_pool *pool, const char *fmt, ...);
+
 /*
  * Move the memory associated with the 'src' pool to the 'dst' pool. The 'src'
  * pool will be empty and not contain any memory. It still needs to be free'd
diff --git a/merge-ort.c b/merge-ort.c
index 8617babee4..201f8f7775 100644
--- a/merge-ort.c
+++ b/merge-ort.c
@@ -18,6 +18,7 @@
 #include "merge-ort.h"
 
 #include "alloc.h"
+#include "advice.h"
 #include "attr.h"
 #include "cache-tree.h"
 #include "commit.h"
@@ -542,6 +543,7 @@ enum conflict_and_info_types {
 	CONFLICT_SUBMODULE_HISTORY_NOT_AVAILABLE,
 	CONFLICT_SUBMODULE_MAY_HAVE_REWINDS,
 	CONFLICT_SUBMODULE_NULL_MERGE_BASE,
+	CONFLICT_SUBMODULE_CORRUPT,
 
 	/* Keep this entry _last_ in the list */
 	NB_CONFLICT_TYPES,
@@ -594,7 +596,9 @@ static const char *type_short_descriptions[] = {
 	[CONFLICT_SUBMODULE_MAY_HAVE_REWINDS] =
 		"CONFLICT (submodule may have rewinds)",
 	[CONFLICT_SUBMODULE_NULL_MERGE_BASE] =
-		"CONFLICT (submodule lacks merge base)"
+		"CONFLICT (submodule lacks merge base)",
+	[CONFLICT_SUBMODULE_CORRUPT] =
+		"CONFLICT (submodule corrupt)"
 };
 
 struct logical_conflict_info {
@@ -1657,9 +1661,10 @@ static int collect_merge_info(struct merge_options *opt,
 	info.data = opt;
 	info.show_all_errors = 1;
 
-	parse_tree(merge_base);
-	parse_tree(side1);
-	parse_tree(side2);
+	if (parse_tree(merge_base) < 0 ||
+	    parse_tree(side1) < 0 ||
+	    parse_tree(side2) < 0)
+		return -1;
 	init_tree_desc(t + 0, merge_base->buffer, merge_base->size);
 	init_tree_desc(t + 1, side1->buffer, side1->size);
 	init_tree_desc(t + 2, side2->buffer, side2->size);
@@ -1708,7 +1713,14 @@ static int find_first_merges(struct repository *repo,
 		die("revision walk setup failed");
 	while ((commit = get_revision(&revs)) != NULL) {
 		struct object *o = &(commit->object);
-		if (repo_in_merge_bases(repo, b, commit))
+		int ret = repo_in_merge_bases(repo, b, commit);
+
+		if (ret < 0) {
+			object_array_clear(&merges);
+			release_revisions(&revs);
+			return ret;
+		}
+		if (ret > 0)
 			add_object_array(o, NULL, &merges);
 	}
 	reset_revision_walk();
@@ -1723,9 +1735,17 @@ static int find_first_merges(struct repository *repo,
 		contains_another = 0;
 		for (j = 0; j < merges.nr; j++) {
 			struct commit *m2 = (struct commit *) merges.objects[j].item;
-			if (i != j && repo_in_merge_bases(repo, m2, m1)) {
-				contains_another = 1;
-				break;
+			if (i != j) {
+				int ret = repo_in_merge_bases(repo, m2, m1);
+				if (ret < 0) {
+					object_array_clear(&merges);
+					release_revisions(&revs);
+					return ret;
+				}
+				if (ret > 0) {
+					contains_another = 1;
+					break;
+				}
 			}
 		}
 
@@ -1747,7 +1767,7 @@ static int merge_submodule(struct merge_options *opt,
 {
 	struct repository subrepo;
 	struct strbuf sb = STRBUF_INIT;
-	int ret = 0;
+	int ret = 0, ret2;
 	struct commit *commit_o, *commit_a, *commit_b;
 	int parent_count;
 	struct object_array merges;
@@ -1794,8 +1814,28 @@ static int merge_submodule(struct merge_options *opt,
 	}
 
 	/* check whether both changes are forward */
-	if (!repo_in_merge_bases(&subrepo, commit_o, commit_a) ||
-	    !repo_in_merge_bases(&subrepo, commit_o, commit_b)) {
+	ret2 = repo_in_merge_bases(&subrepo, commit_o, commit_a);
+	if (ret2 < 0) {
+		path_msg(opt, CONFLICT_SUBMODULE_CORRUPT, 0,
+			 path, NULL, NULL, NULL,
+			 _("Failed to merge submodule %s "
+			   "(repository corrupt)"),
+			 path);
+		ret = -1;
+		goto cleanup;
+	}
+	if (ret2 > 0)
+		ret2 = repo_in_merge_bases(&subrepo, commit_o, commit_b);
+	if (ret2 < 0) {
+		path_msg(opt, CONFLICT_SUBMODULE_CORRUPT, 0,
+			 path, NULL, NULL, NULL,
+			 _("Failed to merge submodule %s "
+			   "(repository corrupt)"),
+			 path);
+		ret = -1;
+		goto cleanup;
+	}
+	if (!ret2) {
 		path_msg(opt, CONFLICT_SUBMODULE_MAY_HAVE_REWINDS, 0,
 			 path, NULL, NULL, NULL,
 			 _("Failed to merge submodule %s "
@@ -1805,7 +1845,17 @@ static int merge_submodule(struct merge_options *opt,
 	}
 
 	/* Case #1: a is contained in b or vice versa */
-	if (repo_in_merge_bases(&subrepo, commit_a, commit_b)) {
+	ret2 = repo_in_merge_bases(&subrepo, commit_a, commit_b);
+	if (ret2 < 0) {
+		path_msg(opt, CONFLICT_SUBMODULE_CORRUPT, 0,
+			 path, NULL, NULL, NULL,
+			 _("Failed to merge submodule %s "
+			   "(repository corrupt)"),
+			 path);
+		ret = -1;
+		goto cleanup;
+	}
+	if (ret2 > 0) {
 		oidcpy(result, b);
 		path_msg(opt, INFO_SUBMODULE_FAST_FORWARDING, 1,
 			 path, NULL, NULL, NULL,
@@ -1814,7 +1864,17 @@ static int merge_submodule(struct merge_options *opt,
 		ret = 1;
 		goto cleanup;
 	}
-	if (repo_in_merge_bases(&subrepo, commit_b, commit_a)) {
+	ret2 = repo_in_merge_bases(&subrepo, commit_b, commit_a);
+	if (ret2 < 0) {
+		path_msg(opt, CONFLICT_SUBMODULE_CORRUPT, 0,
+			 path, NULL, NULL, NULL,
+			 _("Failed to merge submodule %s "
+			   "(repository corrupt)"),
+			 path);
+		ret = -1;
+		goto cleanup;
+	}
+	if (ret2 > 0) {
 		oidcpy(result, a);
 		path_msg(opt, INFO_SUBMODULE_FAST_FORWARDING, 1,
 			 path, NULL, NULL, NULL,
@@ -1839,6 +1899,14 @@ static int merge_submodule(struct merge_options *opt,
 	parent_count = find_first_merges(&subrepo, path, commit_a, commit_b,
 					 &merges);
 	switch (parent_count) {
+	case -1:
+		path_msg(opt, CONFLICT_SUBMODULE_CORRUPT, 0,
+			 path, NULL, NULL, NULL,
+			 _("Failed to merge submodule %s "
+			   "(repository corrupt)"),
+			 path);
+		ret = -1;
+		break;
 	case 0:
 		path_msg(opt, CONFLICT_SUBMODULE_FAILED_TO_MERGE, 0,
 			 path, NULL, NULL, NULL,
@@ -4376,9 +4444,11 @@ static int checkout(struct merge_options *opt,
 	unpack_opts.verbose_update = (opt->verbosity > 2);
 	unpack_opts.fn = twoway_merge;
 	unpack_opts.preserve_ignored = 0; /* FIXME: !opts->overwrite_ignore */
-	parse_tree(prev);
+	if (parse_tree(prev) < 0)
+		return -1;
 	init_tree_desc(&trees[0], prev->buffer, prev->size);
-	parse_tree(next);
+	if (parse_tree(next) < 0)
+		return -1;
 	init_tree_desc(&trees[1], next->buffer, next->size);
 
 	ret = unpack_trees(2, trees, &unpack_opts);
@@ -4556,7 +4626,7 @@ static void print_submodule_conflict_suggestion(struct string_list *csub) {
 		      " - commit the resulting index in the superproject\n"),
 		    tmp.buf, subs.buf);
 
-	printf("%s", msg.buf);
+	advise_if_enabled(ADVICE_SUBMODULE_MERGE_CONFLICT, "%s", msg.buf);
 
 	strbuf_release(&subs);
 	strbuf_release(&tmp);
@@ -4982,6 +5052,9 @@ redo:
 
 	if (result->clean >= 0) {
 		result->tree = parse_tree_indirect(&working_tree_oid);
+		if (!result->tree)
+			die(_("unable to read tree (%s)"),
+			    oid_to_hex(&working_tree_oid));
 		/* existence of conflicted entries implies unclean */
 		result->clean &= strmap_empty(&opt->priv->conflicted);
 	}
@@ -5007,7 +5080,11 @@ static void merge_ort_internal(struct merge_options *opt,
 	struct strbuf merge_base_abbrev = STRBUF_INIT;
 
 	if (!merge_bases) {
-		merge_bases = repo_get_merge_bases(the_repository, h1, h2);
+		if (repo_get_merge_bases(the_repository, h1, h2,
+					 &merge_bases) < 0) {
+			result->clean = -1;
+			return;
+		}
 		/* See merge-ort.h:merge_incore_recursive() declaration NOTE */
 		merge_bases = reverse_commit_list(merge_bases);
 	}
diff --git a/merge-recursive.c b/merge-recursive.c
index a0c3e7a2d9..103ee321ae 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -405,7 +405,8 @@ static inline int merge_detect_rename(struct merge_options *opt)
 
 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 {
-	parse_tree(tree);
+	if (parse_tree(tree) < 0)
+		exit(128);
 	init_tree_desc(desc, tree->buffer, tree->size);
 }
 
@@ -1139,7 +1140,13 @@ static int find_first_merges(struct repository *repo,
 		die("revision walk setup failed");
 	while ((commit = get_revision(&revs)) != NULL) {
 		struct object *o = &(commit->object);
-		if (repo_in_merge_bases(repo, b, commit))
+		int ret = repo_in_merge_bases(repo, b, commit);
+		if (ret < 0) {
+			object_array_clear(&merges);
+			release_revisions(&revs);
+			return ret;
+		}
+		if (ret)
 			add_object_array(o, NULL, &merges);
 	}
 	reset_revision_walk();
@@ -1154,9 +1161,17 @@ static int find_first_merges(struct repository *repo,
 		contains_another = 0;
 		for (j = 0; j < merges.nr; j++) {
 			struct commit *m2 = (struct commit *) merges.objects[j].item;
-			if (i != j && repo_in_merge_bases(repo, m2, m1)) {
-				contains_another = 1;
-				break;
+			if (i != j) {
+				int ret = repo_in_merge_bases(repo, m2, m1);
+				if (ret < 0) {
+					object_array_clear(&merges);
+					release_revisions(&revs);
+					return ret;
+				}
+				if (ret > 0) {
+					contains_another = 1;
+					break;
+				}
 			}
 		}
 
@@ -1192,7 +1207,7 @@ static int merge_submodule(struct merge_options *opt,
 			   const struct object_id *b)
 {
 	struct repository subrepo;
-	int ret = 0;
+	int ret = 0, ret2;
 	struct commit *commit_base, *commit_a, *commit_b;
 	int parent_count;
 	struct object_array merges;
@@ -1229,14 +1244,32 @@ static int merge_submodule(struct merge_options *opt,
 	}
 
 	/* check whether both changes are forward */
-	if (!repo_in_merge_bases(&subrepo, commit_base, commit_a) ||
-	    !repo_in_merge_bases(&subrepo, commit_base, commit_b)) {
+	ret2 = repo_in_merge_bases(&subrepo, commit_base, commit_a);
+	if (ret2 < 0) {
+		output(opt, 1, _("Failed to merge submodule %s (repository corrupt)"), path);
+		ret = -1;
+		goto cleanup;
+	}
+	if (ret2 > 0)
+		ret2 = repo_in_merge_bases(&subrepo, commit_base, commit_b);
+	if (ret2 < 0) {
+		output(opt, 1, _("Failed to merge submodule %s (repository corrupt)"), path);
+		ret = -1;
+		goto cleanup;
+	}
+	if (!ret2) {
 		output(opt, 1, _("Failed to merge submodule %s (commits don't follow merge-base)"), path);
 		goto cleanup;
 	}
 
 	/* Case #1: a is contained in b or vice versa */
-	if (repo_in_merge_bases(&subrepo, commit_a, commit_b)) {
+	ret2 = repo_in_merge_bases(&subrepo, commit_a, commit_b);
+	if (ret2 < 0) {
+		output(opt, 1, _("Failed to merge submodule %s (repository corrupt)"), path);
+		ret = -1;
+		goto cleanup;
+	}
+	if (ret2) {
 		oidcpy(result, b);
 		if (show(opt, 3)) {
 			output(opt, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
@@ -1249,7 +1282,13 @@ static int merge_submodule(struct merge_options *opt,
 		ret = 1;
 		goto cleanup;
 	}
-	if (repo_in_merge_bases(&subrepo, commit_b, commit_a)) {
+	ret2 = repo_in_merge_bases(&subrepo, commit_b, commit_a);
+	if (ret2 < 0) {
+		output(opt, 1, _("Failed to merge submodule %s (repository corrupt)"), path);
+		ret = -1;
+		goto cleanup;
+	}
+	if (ret2) {
 		oidcpy(result, a);
 		if (show(opt, 3)) {
 			output(opt, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
@@ -1278,6 +1317,10 @@ static int merge_submodule(struct merge_options *opt,
 	parent_count = find_first_merges(&subrepo, &merges, path,
 					 commit_a, commit_b);
 	switch (parent_count) {
+	case -1:
+		output(opt, 1,_("Failed to merge submodule %s (repository corrupt)"), path);
+		ret = -1;
+		break;
 	case 0:
 		output(opt, 1, _("Failed to merge submodule %s (merge following commits not found)"), path);
 		break;
@@ -1392,11 +1435,14 @@ static int merge_mode_and_contents(struct merge_options *opt,
 			/* FIXME: bug, what if modes didn't match? */
 			result->clean = (merge_status == 0);
 		} else if (S_ISGITLINK(a->mode)) {
-			result->clean = merge_submodule(opt, &result->blob.oid,
-							o->path,
-							&o->oid,
-							&a->oid,
-							&b->oid);
+			int clean = merge_submodule(opt, &result->blob.oid,
+						    o->path,
+						    &o->oid,
+						    &a->oid,
+						    &b->oid);
+			if (clean < 0)
+				return -1;
+			result->clean = clean;
 		} else if (S_ISLNK(a->mode)) {
 			switch (opt->recursive_variant) {
 			case MERGE_VARIANT_NORMAL:
@@ -3597,7 +3643,9 @@ static int merge_recursive_internal(struct merge_options *opt,
 	}
 
 	if (!merge_bases) {
-		merge_bases = repo_get_merge_bases(the_repository, h1, h2);
+		if (repo_get_merge_bases(the_repository, h1, h2,
+					 &merge_bases) < 0)
+			return -1;
 		merge_bases = reverse_commit_list(merge_bases);
 	}
 
diff --git a/merge.c b/merge.c
index ca89b312d1..563281b10f 100644
--- a/merge.c
+++ b/merge.c
@@ -77,7 +77,10 @@ int checkout_fast_forward(struct repository *r,
 		return -1;
 	}
 	for (i = 0; i < nr_trees; i++) {
-		parse_tree(trees[i]);
+		if (parse_tree(trees[i]) < 0) {
+			rollback_lock_file(&lock_file);
+			return -1;
+		}
 		init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
 	}
 
diff --git a/mergetools/vimdiff b/mergetools/vimdiff
index 06937acbf5..97e376329b 100644
--- a/mergetools/vimdiff
+++ b/mergetools/vimdiff
@@ -371,9 +371,17 @@ diff_cmd_help () {
 
 
 merge_cmd () {
-	layout=$(git config mergetool.vimdiff.layout)
+	TOOL=$1
 
-	case "$1" in
+	layout=$(git config "mergetool.$TOOL.layout")
+
+	# backward compatibility:
+	if test -z "$layout"
+	then
+		layout=$(git config mergetool.vimdiff.layout)
+	fi
+
+	case "$TOOL" in
 	*vimdiff)
 		if test -z "$layout"
 		then
diff --git a/neue b/neue
deleted file mode 100644
index e69de29bb2..0000000000
diff --git a/notes-merge.c b/notes-merge.c
index 8799b522a5..51282934ae 100644
--- a/notes-merge.c
+++ b/notes-merge.c
@@ -607,7 +607,8 @@ int notes_merge(struct notes_merge_options *o,
 	assert(local && remote);
 
 	/* Find merge bases */
-	bases = repo_get_merge_bases(the_repository, local, remote);
+	if (repo_get_merge_bases(the_repository, local, remote, &bases) < 0)
+		exit(128);
 	if (!bases) {
 		base_oid = null_oid();
 		base_tree_oid = the_hash_algo->empty_tree;
diff --git a/object-name.c b/object-name.c
index 3a2ef5d680..bd77695d7e 100644
--- a/object-name.c
+++ b/object-name.c
@@ -1034,6 +1034,15 @@ static int get_oid_basic(struct repository *r, const char *str, int len,
 						len, str,
 						show_date(co_time, co_tz, DATE_MODE(RFC2822)));
 				}
+			} else if (nth == co_cnt && !is_null_oid(oid)) {
+				/*
+				 * We were asked for the Nth reflog (counting
+				 * from 0), but there were only N entries.
+				 * read_ref_at() will have returned "1" to tell
+				 * us it did not find an entry, but it did
+				 * still fill in the oid with the "old" value,
+				 * which we can use.
+				 */
 			} else {
 				if (flags & GET_OID_QUIETLY) {
 					exit(128);
@@ -1479,7 +1488,7 @@ int repo_get_oid_mb(struct repository *r,
 		    struct object_id *oid)
 {
 	struct commit *one, *two;
-	struct commit_list *mbs;
+	struct commit_list *mbs = NULL;
 	struct object_id oid_tmp;
 	const char *dots;
 	int st;
@@ -1507,7 +1516,10 @@ int repo_get_oid_mb(struct repository *r,
 	two = lookup_commit_reference_gently(r, &oid_tmp, 0);
 	if (!two)
 		return -1;
-	mbs = repo_get_merge_bases(r, one, two);
+	if (repo_get_merge_bases(r, one, two, &mbs) < 0) {
+		free_commit_list(mbs);
+		return -1;
+	}
 	if (!mbs || mbs->next)
 		st = -1;
 	else {
diff --git a/object.c b/object.c
index e6a1c4d905..f11c59ac0c 100644
--- a/object.c
+++ b/object.c
@@ -271,6 +271,7 @@ struct object *parse_object_with_flags(struct repository *r,
 				       enum parse_object_flags flags)
 {
 	int skip_hash = !!(flags & PARSE_OBJECT_SKIP_HASH_CHECK);
+	int discard_tree = !!(flags & PARSE_OBJECT_DISCARD_TREE);
 	unsigned long size;
 	enum object_type type;
 	int eaten;
@@ -298,6 +299,17 @@ struct object *parse_object_with_flags(struct repository *r,
 		return lookup_object(r, oid);
 	}
 
+	/*
+	 * If the caller does not care about the tree buffer and does not
+	 * care about checking the hash, we can simply verify that we
+	 * have the on-disk object with the correct type.
+	 */
+	if (skip_hash && discard_tree &&
+	    (!obj || obj->type == OBJ_TREE) &&
+	    oid_object_info(r, oid, NULL) == OBJ_TREE) {
+		return &lookup_tree(r, oid)->object;
+	}
+
 	buffer = repo_read_object_file(r, oid, &type, &size);
 	if (buffer) {
 		if (!skip_hash &&
@@ -311,6 +323,8 @@ struct object *parse_object_with_flags(struct repository *r,
 					  buffer, &eaten);
 		if (!eaten)
 			free(buffer);
+		if (discard_tree && type == OBJ_TREE)
+			free_tree_buffer((struct tree *)obj);
 		return obj;
 	}
 	return NULL;
diff --git a/object.h b/object.h
index 114d45954d..c7123cade6 100644
--- a/object.h
+++ b/object.h
@@ -197,6 +197,7 @@ void *object_as_type(struct object *obj, enum object_type type, int quiet);
  */
 enum parse_object_flags {
 	PARSE_OBJECT_SKIP_HASH_CHECK = 1 << 0,
+	PARSE_OBJECT_DISCARD_TREE = 1 << 1,
 };
 struct object *parse_object(struct repository *r, const struct object_id *oid);
 struct object *parse_object_with_flags(struct repository *r,
diff --git a/oidset.c b/oidset.c
index d1e5376316..91d1385910 100644
--- a/oidset.c
+++ b/oidset.c
@@ -23,6 +23,16 @@ int oidset_insert(struct oidset *set, const struct object_id *oid)
 	return !added;
 }
 
+void oidset_insert_from_set(struct oidset *dest, struct oidset *src)
+{
+	struct oidset_iter iter;
+	struct object_id *src_oid;
+
+	oidset_iter_init(src, &iter);
+	while ((src_oid = oidset_iter_next(&iter)))
+		oidset_insert(dest, src_oid);
+}
+
 int oidset_remove(struct oidset *set, const struct object_id *oid)
 {
 	khiter_t pos = kh_get_oid_set(&set->set, *oid);
diff --git a/oidset.h b/oidset.h
index ba4a5a2cd3..262f4256d6 100644
--- a/oidset.h
+++ b/oidset.h
@@ -47,6 +47,12 @@ int oidset_contains(const struct oidset *set, const struct object_id *oid);
  */
 int oidset_insert(struct oidset *set, const struct object_id *oid);
 
+/**
+ * Insert all the oids that are in set 'src' into set 'dest'; a copy
+ * is made of each oid inserted into set 'dest'.
+ */
+void oidset_insert_from_set(struct oidset *dest, struct oidset *src);
+
 /**
  * Remove the oid from the set.
  *
diff --git a/ref-filter.c b/ref-filter.c
index be14b56e32..0ec29f7385 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -2628,6 +2628,12 @@ static int for_each_fullref_in_pattern(struct ref_filter *filter,
 				       each_ref_fn cb,
 				       void *cb_data)
 {
+	if (filter->kind == FILTER_REFS_KIND_MASK) {
+		/* In this case, we want to print all refs including root refs. */
+		return refs_for_each_include_root_refs(get_main_ref_store(the_repository),
+						       cb, cb_data);
+	}
+
 	if (!filter->match_as_path) {
 		/*
 		 * in this case, the patterns are applied after
@@ -2750,6 +2756,9 @@ static int ref_kind_from_refname(const char *refname)
 			return ref_kind[i].kind;
 	}
 
+	if (is_pseudoref(get_main_ref_store(the_repository), refname))
+		return FILTER_REFS_PSEUDOREFS;
+
 	return FILTER_REFS_OTHERS;
 }
 
@@ -2781,7 +2790,16 @@ static struct ref_array_item *apply_ref_filter(const char *refname, const struct
 
 	/* Obtain the current ref kind from filter_ref_kind() and ignore unwanted refs. */
 	kind = filter_ref_kind(filter, refname);
-	if (!(kind & filter->kind))
+
+	/*
+	 * Generally HEAD refs are printed with special description denoting a rebase,
+	 * detached state and so forth. This is useful when only printing the HEAD ref
+	 * But when it is being printed along with other pseudorefs, it makes sense to
+	 * keep the formatting consistent. So we mask the type to act like a pseudoref.
+	 */
+	if (filter->kind == FILTER_REFS_KIND_MASK && kind == FILTER_REFS_DETACHED_HEAD)
+		kind = FILTER_REFS_PSEUDOREFS;
+	else if (!(kind & filter->kind))
 		return NULL;
 
 	if (!filter_pattern_match(filter, refname))
@@ -3047,9 +3065,15 @@ static int do_filter_refs(struct ref_filter *filter, unsigned int type, each_ref
 			ret = for_each_fullref_in("refs/remotes/", fn, cb_data);
 		else if (filter->kind == FILTER_REFS_TAGS)
 			ret = for_each_fullref_in("refs/tags/", fn, cb_data);
-		else if (filter->kind & FILTER_REFS_ALL)
+		else if (filter->kind & FILTER_REFS_REGULAR)
 			ret = for_each_fullref_in_pattern(filter, fn, cb_data);
-		if (!ret && (filter->kind & FILTER_REFS_DETACHED_HEAD))
+
+		/*
+		 * When printing all ref types, HEAD is already included,
+		 * so we don't want to print HEAD again.
+		 */
+		if (!ret && (filter->kind != FILTER_REFS_KIND_MASK) &&
+		    (filter->kind & FILTER_REFS_DETACHED_HEAD))
 			head_ref(fn, cb_data);
 	}
 
diff --git a/ref-filter.h b/ref-filter.h
index 07cd6f6da3..0ca28d2bba 100644
--- a/ref-filter.h
+++ b/ref-filter.h
@@ -19,10 +19,13 @@
 #define FILTER_REFS_BRANCHES       0x0004
 #define FILTER_REFS_REMOTES        0x0008
 #define FILTER_REFS_OTHERS         0x0010
-#define FILTER_REFS_ALL            (FILTER_REFS_TAGS | FILTER_REFS_BRANCHES | \
+#define FILTER_REFS_REGULAR        (FILTER_REFS_TAGS | FILTER_REFS_BRANCHES | \
 				    FILTER_REFS_REMOTES | FILTER_REFS_OTHERS)
 #define FILTER_REFS_DETACHED_HEAD  0x0020
-#define FILTER_REFS_KIND_MASK      (FILTER_REFS_ALL | FILTER_REFS_DETACHED_HEAD)
+#define FILTER_REFS_PSEUDOREFS     0x0040
+#define FILTER_REFS_ROOT_REFS      (FILTER_REFS_DETACHED_HEAD | FILTER_REFS_PSEUDOREFS)
+#define FILTER_REFS_KIND_MASK      (FILTER_REFS_REGULAR | FILTER_REFS_DETACHED_HEAD | \
+				    FILTER_REFS_PSEUDOREFS)
 
 struct atom_value;
 struct ref_sorting;
diff --git a/refs.c b/refs.c
index fff343c256..55d2e0b2cb 100644
--- a/refs.c
+++ b/refs.c
@@ -860,6 +860,47 @@ static int is_pseudoref_syntax(const char *refname)
 	return 1;
 }
 
+int is_pseudoref(struct ref_store *refs, const char *refname)
+{
+	static const char *const irregular_pseudorefs[] = {
+		"AUTO_MERGE",
+		"BISECT_EXPECTED_REV",
+		"NOTES_MERGE_PARTIAL",
+		"NOTES_MERGE_REF",
+		"MERGE_AUTOSTASH",
+	};
+	struct object_id oid;
+	size_t i;
+
+	if (!is_pseudoref_syntax(refname))
+		return 0;
+
+	if (ends_with(refname, "_HEAD")) {
+		refs_resolve_ref_unsafe(refs, refname,
+					RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
+					&oid, NULL);
+		return !is_null_oid(&oid);
+	}
+
+	for (i = 0; i < ARRAY_SIZE(irregular_pseudorefs); i++)
+		if (!strcmp(refname, irregular_pseudorefs[i])) {
+			refs_resolve_ref_unsafe(refs, refname,
+						RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
+						&oid, NULL);
+			return !is_null_oid(&oid);
+		}
+
+	return 0;
+}
+
+int is_headref(struct ref_store *refs, const char *refname)
+{
+	if (!strcmp(refname, "HEAD"))
+		return refs_ref_exists(refs, refname);
+
+	return 0;
+}
+
 static int is_current_worktree_ref(const char *ref) {
 	return is_pseudoref_syntax(ref) || is_per_worktree_ref(ref);
 }
@@ -1039,55 +1080,40 @@ static int read_ref_at_ent(struct object_id *ooid, struct object_id *noid,
 			   const char *message, void *cb_data)
 {
 	struct read_ref_at_cb *cb = cb_data;
-	int reached_count;
 
 	cb->tz = tz;
 	cb->date = timestamp;
 
-	/*
-	 * It is not possible for cb->cnt == 0 on the first iteration because
-	 * that special case is handled in read_ref_at().
-	 */
-	if (cb->cnt > 0)
-		cb->cnt--;
-	reached_count = cb->cnt == 0 && !is_null_oid(ooid);
-	if (timestamp <= cb->at_time || reached_count) {
+	if (timestamp <= cb->at_time || cb->cnt == 0) {
 		set_read_ref_cutoffs(cb, timestamp, tz, message);
 		/*
 		 * we have not yet updated cb->[n|o]oid so they still
 		 * hold the values for the previous record.
 		 */
-		if (!is_null_oid(&cb->ooid) && !oideq(&cb->ooid, noid))
-			warning(_("log for ref %s has gap after %s"),
+		if (!is_null_oid(&cb->ooid)) {
+			oidcpy(cb->oid, noid);
+			if (!oideq(&cb->ooid, noid))
+				warning(_("log for ref %s has gap after %s"),
 					cb->refname, show_date(cb->date, cb->tz, DATE_MODE(RFC2822)));
-		if (reached_count)
-			oidcpy(cb->oid, ooid);
-		else if (!is_null_oid(&cb->ooid) || cb->date == cb->at_time)
+		}
+		else if (cb->date == cb->at_time)
 			oidcpy(cb->oid, noid);
 		else if (!oideq(noid, cb->oid))
 			warning(_("log for ref %s unexpectedly ended on %s"),
 				cb->refname, show_date(cb->date, cb->tz,
 						       DATE_MODE(RFC2822)));
+		cb->reccnt++;
+		oidcpy(&cb->ooid, ooid);
+		oidcpy(&cb->noid, noid);
 		cb->found_it = 1;
+		return 1;
 	}
 	cb->reccnt++;
 	oidcpy(&cb->ooid, ooid);
 	oidcpy(&cb->noid, noid);
-	return cb->found_it;
-}
-
-static int read_ref_at_ent_newest(struct object_id *ooid UNUSED,
-				  struct object_id *noid,
-				  const char *email UNUSED,
-				  timestamp_t timestamp, int tz,
-				  const char *message, void *cb_data)
-{
-	struct read_ref_at_cb *cb = cb_data;
-
-	set_read_ref_cutoffs(cb, timestamp, tz, message);
-	oidcpy(cb->oid, noid);
-	/* We just want the first entry */
-	return 1;
+	if (cb->cnt > 0)
+		cb->cnt--;
+	return 0;
 }
 
 static int read_ref_at_ent_oldest(struct object_id *ooid, struct object_id *noid,
@@ -1099,7 +1125,7 @@ static int read_ref_at_ent_oldest(struct object_id *ooid, struct object_id *noid
 
 	set_read_ref_cutoffs(cb, timestamp, tz, message);
 	oidcpy(cb->oid, ooid);
-	if (is_null_oid(cb->oid))
+	if (cb->at_time && is_null_oid(cb->oid))
 		oidcpy(cb->oid, noid);
 	/* We just want the first entry */
 	return 1;
@@ -1122,14 +1148,24 @@ int read_ref_at(struct ref_store *refs, const char *refname,
 	cb.cutoff_cnt = cutoff_cnt;
 	cb.oid = oid;
 
-	if (cb.cnt == 0) {
-		refs_for_each_reflog_ent_reverse(refs, refname, read_ref_at_ent_newest, &cb);
-		return 0;
-	}
-
 	refs_for_each_reflog_ent_reverse(refs, refname, read_ref_at_ent, &cb);
 
 	if (!cb.reccnt) {
+		if (cnt == 0) {
+			/*
+			 * The caller asked for ref@{0}, and we had no entries.
+			 * It's a bit subtle, but in practice all callers have
+			 * prepped the "oid" field with the current value of
+			 * the ref, which is the most reasonable fallback.
+			 *
+			 * We'll put dummy values into the out-parameters (so
+			 * they're not just uninitialized garbage), and the
+			 * caller can take our return value as a hint that
+			 * we did not find any such reflog.
+			 */
+			set_read_ref_cutoffs(&cb, 0, 0, "empty reflog");
+			return 1;
+		}
 		if (flags & GET_OID_QUIETLY)
 			exit(128);
 		else
@@ -1594,10 +1630,6 @@ struct ref_iterator *refs_ref_iterator_begin(
 	if (trim)
 		iter = prefix_ref_iterator_begin(iter, "", trim);
 
-	/* Sanity check for subclasses: */
-	if (!iter->ordered)
-		BUG("reference iterator is not ordered");
-
 	return iter;
 }
 
@@ -1724,6 +1756,13 @@ int for_each_rawref(each_ref_fn fn, void *cb_data)
 	return refs_for_each_rawref(get_main_ref_store(the_repository), fn, cb_data);
 }
 
+int refs_for_each_include_root_refs(struct ref_store *refs, each_ref_fn fn,
+				    void *cb_data)
+{
+	return do_for_each_ref(refs, "", NULL, fn, 0,
+			       DO_FOR_EACH_INCLUDE_ROOT_REFS, cb_data);
+}
+
 static int qsort_strcmp(const void *va, const void *vb)
 {
 	const char *a = *(const char **)va;
@@ -2516,18 +2555,33 @@ cleanup:
 	return ret;
 }
 
-int refs_for_each_reflog(struct ref_store *refs, each_ref_fn fn, void *cb_data)
+struct do_for_each_reflog_help {
+	each_reflog_fn *fn;
+	void *cb_data;
+};
+
+static int do_for_each_reflog_helper(struct repository *r UNUSED,
+				     const char *refname,
+				     const struct object_id *oid UNUSED,
+				     int flags,
+				     void *cb_data)
+{
+	struct do_for_each_reflog_help *hp = cb_data;
+	return hp->fn(refname, hp->cb_data);
+}
+
+int refs_for_each_reflog(struct ref_store *refs, each_reflog_fn fn, void *cb_data)
 {
 	struct ref_iterator *iter;
-	struct do_for_each_ref_help hp = { fn, cb_data };
+	struct do_for_each_reflog_help hp = { fn, cb_data };
 
 	iter = refs->be->reflog_iterator_begin(refs);
 
 	return do_for_each_repo_ref_iterator(the_repository, iter,
-					     do_for_each_ref_helper, &hp);
+					     do_for_each_reflog_helper, &hp);
 }
 
-int for_each_reflog(each_ref_fn fn, void *cb_data)
+int for_each_reflog(each_reflog_fn fn, void *cb_data)
 {
 	return refs_for_each_reflog(get_main_ref_store(the_repository), fn, cb_data);
 }
diff --git a/refs.h b/refs.h
index 303c5fac4d..298caf6c61 100644
--- a/refs.h
+++ b/refs.h
@@ -398,6 +398,12 @@ int for_each_namespaced_ref(const char **exclude_patterns,
 int refs_for_each_rawref(struct ref_store *refs, each_ref_fn fn, void *cb_data);
 int for_each_rawref(each_ref_fn fn, void *cb_data);
 
+/*
+ * Iterates over all refs including root refs, i.e. pseudorefs and HEAD.
+ */
+int refs_for_each_include_root_refs(struct ref_store *refs, each_ref_fn fn,
+				    void *cb_data);
+
 /*
  * Normalizes partial refs to their fully qualified form.
  * Will prepend <prefix> to the <pattern> if it doesn't start with 'refs/'.
@@ -440,7 +446,20 @@ int refs_create_reflog(struct ref_store *refs, const char *refname,
 		       struct strbuf *err);
 int safe_create_reflog(const char *refname, struct strbuf *err);
 
-/** Reads log for the value of ref during at_time. **/
+/**
+ * Reads log for the value of ref during at_time (in which case "cnt" should be
+ * negative) or the reflog "cnt" entries from the top (in which case "at_time"
+ * should be 0).
+ *
+ * If we found the reflog entry in question, returns 0 (and details of the
+ * entry can be found in the out-parameters).
+ *
+ * If we ran out of reflog entries, the out-parameters are filled with the
+ * details of the oldest entry we did find, and the function returns 1. Note
+ * that there is one important special case here! If the reflog was empty
+ * and the caller asked for the 0-th cnt, we will return "1" but leave the
+ * "oid" field untouched.
+ **/
 int read_ref_at(struct ref_store *refs,
 		const char *refname, unsigned int flags,
 		timestamp_t at_time, int cnt,
@@ -534,12 +553,19 @@ int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_dat
 /* youngest entry first */
 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data);
 
+/*
+ * The signature for the callback function for the {refs_,}for_each_reflog()
+ * functions below. The memory pointed to by the refname argument is only
+ * guaranteed to be valid for the duration of a single callback invocation.
+ */
+typedef int each_reflog_fn(const char *refname, void *cb_data);
+
 /*
  * Calls the specified function for each reflog file until it returns nonzero,
  * and returns the value. Reflog file order is unspecified.
  */
-int refs_for_each_reflog(struct ref_store *refs, each_ref_fn fn, void *cb_data);
-int for_each_reflog(each_ref_fn fn, void *cb_data);
+int refs_for_each_reflog(struct ref_store *refs, each_reflog_fn fn, void *cb_data);
+int for_each_reflog(each_reflog_fn fn, void *cb_data);
 
 #define REFNAME_ALLOW_ONELEVEL 1
 #define REFNAME_REFSPEC_PATTERN 2
@@ -1023,4 +1049,7 @@ extern struct ref_namespace_info ref_namespace[NAMESPACE__COUNT];
  */
 void update_ref_namespace(enum ref_namespace namespace, char *ref);
 
+int is_pseudoref(struct ref_store *refs, const char *refname);
+int is_headref(struct ref_store *refs, const char *refname);
+
 #endif /* REFS_H */
diff --git a/refs/debug.c b/refs/debug.c
index 634681ca44..c7531b17f0 100644
--- a/refs/debug.c
+++ b/refs/debug.c
@@ -181,7 +181,6 @@ static int debug_ref_iterator_advance(struct ref_iterator *ref_iterator)
 		trace_printf_key(&trace_refs, "iterator_advance: %s (0)\n",
 			diter->iter->refname);
 
-	diter->base.ordered = diter->iter->ordered;
 	diter->base.refname = diter->iter->refname;
 	diter->base.oid = diter->iter->oid;
 	diter->base.flags = diter->iter->flags;
@@ -222,7 +221,7 @@ debug_ref_iterator_begin(struct ref_store *ref_store, const char *prefix,
 		drefs->refs->be->iterator_begin(drefs->refs, prefix,
 						exclude_patterns, flags);
 	struct debug_ref_iterator *diter = xcalloc(1, sizeof(*diter));
-	base_ref_iterator_init(&diter->base, &debug_ref_iterator_vtable, 1);
+	base_ref_iterator_init(&diter->base, &debug_ref_iterator_vtable);
 	diter->iter = res;
 	trace_printf_key(&trace_refs, "ref_iterator_begin: \"%s\" (0x%x)\n",
 			 prefix, flags);
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 75dcc21ecb..a098d14ea0 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -229,6 +229,38 @@ static void add_per_worktree_entries_to_dir(struct ref_dir *dir, const char *dir
 	}
 }
 
+static void loose_fill_ref_dir_regular_file(struct files_ref_store *refs,
+					    const char *refname,
+					    struct ref_dir *dir)
+{
+	struct object_id oid;
+	int flag;
+
+	if (!refs_resolve_ref_unsafe(&refs->base, refname, RESOLVE_REF_READING,
+				     &oid, &flag)) {
+		oidclr(&oid);
+		flag |= REF_ISBROKEN;
+	} else if (is_null_oid(&oid)) {
+		/*
+		 * It is so astronomically unlikely
+		 * that null_oid is the OID of an
+		 * actual object that we consider its
+		 * appearance in a loose reference
+		 * file to be repo corruption
+		 * (probably due to a software bug).
+		 */
+		flag |= REF_ISBROKEN;
+	}
+
+	if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
+		if (!refname_is_safe(refname))
+			die("loose refname is dangerous: %s", refname);
+		oidclr(&oid);
+		flag |= REF_BAD_NAME | REF_ISBROKEN;
+	}
+	add_entry_to_dir(dir, create_ref_entry(refname, &oid, flag));
+}
+
 /*
  * Read the loose references from the namespace dirname into dir
  * (without recursing).  dirname must end with '/'.  dir must be the
@@ -257,8 +289,6 @@ static void loose_fill_ref_dir(struct ref_store *ref_store,
 	strbuf_add(&refname, dirname, dirnamelen);
 
 	while ((de = readdir(d)) != NULL) {
-		struct object_id oid;
-		int flag;
 		unsigned char dtype;
 
 		if (de->d_name[0] == '.')
@@ -274,33 +304,7 @@ static void loose_fill_ref_dir(struct ref_store *ref_store,
 					 create_dir_entry(dir->cache, refname.buf,
 							  refname.len));
 		} else if (dtype == DT_REG) {
-			if (!refs_resolve_ref_unsafe(&refs->base,
-						     refname.buf,
-						     RESOLVE_REF_READING,
-						     &oid, &flag)) {
-				oidclr(&oid);
-				flag |= REF_ISBROKEN;
-			} else if (is_null_oid(&oid)) {
-				/*
-				 * It is so astronomically unlikely
-				 * that null_oid is the OID of an
-				 * actual object that we consider its
-				 * appearance in a loose reference
-				 * file to be repo corruption
-				 * (probably due to a software bug).
-				 */
-				flag |= REF_ISBROKEN;
-			}
-
-			if (check_refname_format(refname.buf,
-						 REFNAME_ALLOW_ONELEVEL)) {
-				if (!refname_is_safe(refname.buf))
-					die("loose refname is dangerous: %s", refname.buf);
-				oidclr(&oid);
-				flag |= REF_BAD_NAME | REF_ISBROKEN;
-			}
-			add_entry_to_dir(dir,
-					 create_ref_entry(refname.buf, &oid, flag));
+			loose_fill_ref_dir_regular_file(refs, refname.buf, dir);
 		}
 		strbuf_setlen(&refname, dirnamelen);
 	}
@@ -311,9 +315,59 @@ static void loose_fill_ref_dir(struct ref_store *ref_store,
 	add_per_worktree_entries_to_dir(dir, dirname);
 }
 
-static struct ref_cache *get_loose_ref_cache(struct files_ref_store *refs)
+/*
+ * Add pseudorefs to the ref dir by parsing the directory for any files
+ * which follow the pseudoref syntax.
+ */
+static void add_pseudoref_and_head_entries(struct ref_store *ref_store,
+					 struct ref_dir *dir,
+					 const char *dirname)
+{
+	struct files_ref_store *refs =
+		files_downcast(ref_store, REF_STORE_READ, "fill_ref_dir");
+	struct strbuf path = STRBUF_INIT, refname = STRBUF_INIT;
+	struct dirent *de;
+	size_t dirnamelen;
+	DIR *d;
+
+	files_ref_path(refs, &path, dirname);
+
+	d = opendir(path.buf);
+	if (!d) {
+		strbuf_release(&path);
+		return;
+	}
+
+	strbuf_addstr(&refname, dirname);
+	dirnamelen = refname.len;
+
+	while ((de = readdir(d)) != NULL) {
+		unsigned char dtype;
+
+		if (de->d_name[0] == '.')
+			continue;
+		if (ends_with(de->d_name, ".lock"))
+			continue;
+		strbuf_addstr(&refname, de->d_name);
+
+		dtype = get_dtype(de, &path, 1);
+		if (dtype == DT_REG && (is_pseudoref(ref_store, de->d_name) ||
+								is_headref(ref_store, de->d_name)))
+			loose_fill_ref_dir_regular_file(refs, refname.buf, dir);
+
+		strbuf_setlen(&refname, dirnamelen);
+	}
+	strbuf_release(&refname);
+	strbuf_release(&path);
+	closedir(d);
+}
+
+static struct ref_cache *get_loose_ref_cache(struct files_ref_store *refs,
+					     unsigned int flags)
 {
 	if (!refs->loose) {
+		struct ref_dir *dir;
+
 		/*
 		 * Mark the top-level directory complete because we
 		 * are about to read the only subdirectory that can
@@ -324,12 +378,17 @@ static struct ref_cache *get_loose_ref_cache(struct files_ref_store *refs)
 		/* We're going to fill the top level ourselves: */
 		refs->loose->root->flag &= ~REF_INCOMPLETE;
 
+		dir = get_ref_dir(refs->loose->root);
+
+		if (flags & DO_FOR_EACH_INCLUDE_ROOT_REFS)
+			add_pseudoref_and_head_entries(dir->cache->ref_store, dir,
+						       refs->loose->root->name);
+
 		/*
 		 * Add an incomplete entry for "refs/" (to be filled
 		 * lazily):
 		 */
-		add_entry_to_dir(get_ref_dir(refs->loose->root),
-				 create_dir_entry(refs->loose, "refs/", 5));
+		add_entry_to_dir(dir, create_dir_entry(refs->loose, "refs/", 5));
 	}
 	return refs->loose;
 }
@@ -857,7 +916,7 @@ static struct ref_iterator *files_ref_iterator_begin(
 	 * disk, and re-reads it if not.
 	 */
 
-	loose_iter = cache_ref_iterator_begin(get_loose_ref_cache(refs),
+	loose_iter = cache_ref_iterator_begin(get_loose_ref_cache(refs, flags),
 					      prefix, ref_store->repo, 1);
 
 	/*
@@ -879,8 +938,7 @@ static struct ref_iterator *files_ref_iterator_begin(
 
 	CALLOC_ARRAY(iter, 1);
 	ref_iterator = &iter->base;
-	base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable,
-			       overlay_iter->ordered);
+	base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);
 	iter->iter0 = overlay_iter;
 	iter->repo = ref_store->repo;
 	iter->flags = flags;
@@ -1218,7 +1276,7 @@ static int files_pack_refs(struct ref_store *ref_store,
 
 	packed_refs_lock(refs->packed_ref_store, LOCK_DIE_ON_ERROR, &err);
 
-	iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), NULL,
+	iter = cache_ref_iterator_begin(get_loose_ref_cache(refs, 0), NULL,
 					the_repository, 0);
 	while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
 		/*
@@ -2116,10 +2174,8 @@ static int files_for_each_reflog_ent(struct ref_store *ref_store,
 
 struct files_reflog_iterator {
 	struct ref_iterator base;
-
 	struct ref_store *ref_store;
 	struct dir_iterator *dir_iterator;
-	struct object_id oid;
 };
 
 static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
@@ -2130,25 +2186,13 @@ static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
 	int ok;
 
 	while ((ok = dir_iterator_advance(diter)) == ITER_OK) {
-		int flags;
-
 		if (!S_ISREG(diter->st.st_mode))
 			continue;
-		if (diter->basename[0] == '.')
+		if (check_refname_format(diter->basename,
+					 REFNAME_ALLOW_ONELEVEL))
 			continue;
-		if (ends_with(diter->basename, ".lock"))
-			continue;
-
-		if (!refs_resolve_ref_unsafe(iter->ref_store,
-					     diter->relative_path, 0,
-					     &iter->oid, &flags)) {
-			error("bad ref for %s", diter->path.buf);
-			continue;
-		}
 
 		iter->base.refname = diter->relative_path;
-		iter->base.oid = &iter->oid;
-		iter->base.flags = flags;
 		return ITER_OK;
 	}
 
@@ -2193,7 +2237,7 @@ static struct ref_iterator *reflog_iterator_begin(struct ref_store *ref_store,
 
 	strbuf_addf(&sb, "%s/logs", gitdir);
 
-	diter = dir_iterator_begin(sb.buf, 0);
+	diter = dir_iterator_begin(sb.buf, DIR_ITERATOR_SORTED);
 	if (!diter) {
 		strbuf_release(&sb);
 		return empty_ref_iterator_begin();
@@ -2202,7 +2246,7 @@ static struct ref_iterator *reflog_iterator_begin(struct ref_store *ref_store,
 	CALLOC_ARRAY(iter, 1);
 	ref_iterator = &iter->base;
 
-	base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable, 0);
+	base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
 	iter->dir_iterator = diter;
 	iter->ref_store = ref_store;
 	strbuf_release(&sb);
@@ -2210,32 +2254,6 @@ static struct ref_iterator *reflog_iterator_begin(struct ref_store *ref_store,
 	return ref_iterator;
 }
 
-static enum iterator_selection reflog_iterator_select(
-	struct ref_iterator *iter_worktree,
-	struct ref_iterator *iter_common,
-	void *cb_data UNUSED)
-{
-	if (iter_worktree) {
-		/*
-		 * We're a bit loose here. We probably should ignore
-		 * common refs if they are accidentally added as
-		 * per-worktree refs.
-		 */
-		return ITER_SELECT_0;
-	} else if (iter_common) {
-		if (parse_worktree_ref(iter_common->refname, NULL, NULL,
-				       NULL) == REF_WORKTREE_SHARED)
-			return ITER_SELECT_1;
-
-		/*
-		 * The main ref store may contain main worktree's
-		 * per-worktree refs, which should be ignored
-		 */
-		return ITER_SKIP_1;
-	} else
-		return ITER_DONE;
-}
-
 static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
 {
 	struct files_ref_store *refs =
@@ -2246,9 +2264,9 @@ static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_st
 		return reflog_iterator_begin(ref_store, refs->gitcommondir);
 	} else {
 		return merge_ref_iterator_begin(
-			0, reflog_iterator_begin(ref_store, refs->base.gitdir),
+			reflog_iterator_begin(ref_store, refs->base.gitdir),
 			reflog_iterator_begin(ref_store, refs->gitcommondir),
-			reflog_iterator_select, refs);
+			ref_iterator_select, refs);
 	}
 }
 
diff --git a/refs/iterator.c b/refs/iterator.c
index 6b680f610e..9db8b056d5 100644
--- a/refs/iterator.c
+++ b/refs/iterator.c
@@ -25,11 +25,9 @@ int ref_iterator_abort(struct ref_iterator *ref_iterator)
 }
 
 void base_ref_iterator_init(struct ref_iterator *iter,
-			    struct ref_iterator_vtable *vtable,
-			    int ordered)
+			    struct ref_iterator_vtable *vtable)
 {
 	iter->vtable = vtable;
-	iter->ordered = !!ordered;
 	iter->refname = NULL;
 	iter->oid = NULL;
 	iter->flags = 0;
@@ -74,7 +72,7 @@ struct ref_iterator *empty_ref_iterator_begin(void)
 	struct empty_ref_iterator *iter = xcalloc(1, sizeof(*iter));
 	struct ref_iterator *ref_iterator = &iter->base;
 
-	base_ref_iterator_init(ref_iterator, &empty_ref_iterator_vtable, 1);
+	base_ref_iterator_init(ref_iterator, &empty_ref_iterator_vtable);
 	return ref_iterator;
 }
 
@@ -98,6 +96,49 @@ struct merge_ref_iterator {
 	struct ref_iterator **current;
 };
 
+enum iterator_selection ref_iterator_select(struct ref_iterator *iter_worktree,
+					    struct ref_iterator *iter_common,
+					    void *cb_data UNUSED)
+{
+	if (iter_worktree && !iter_common) {
+		/*
+		 * Return the worktree ref if there are no more common refs.
+		 */
+		return ITER_SELECT_0;
+	} else if (iter_common) {
+		/*
+		 * In case we have pending worktree and common refs we need to
+		 * yield them based on their lexicographical order. Worktree
+		 * refs that have the same name as common refs shadow the
+		 * latter.
+		 */
+		if (iter_worktree) {
+			int cmp = strcmp(iter_worktree->refname,
+					 iter_common->refname);
+			if (cmp < 0)
+				return ITER_SELECT_0;
+			else if (!cmp)
+				return ITER_SELECT_0_SKIP_1;
+		}
+
+		 /*
+		  * We now know that the lexicographically-next ref is a common
+		  * ref. When the common ref is a shared one we return it.
+		  */
+		if (parse_worktree_ref(iter_common->refname, NULL, NULL,
+				       NULL) == REF_WORKTREE_SHARED)
+			return ITER_SELECT_1;
+
+		/*
+		 * Otherwise, if the common ref is a per-worktree ref we skip
+		 * it because it would belong to the main worktree, not ours.
+		 */
+		return ITER_SKIP_1;
+	} else {
+		return ITER_DONE;
+	}
+}
+
 static int merge_ref_iterator_advance(struct ref_iterator *ref_iterator)
 {
 	struct merge_ref_iterator *iter =
@@ -207,7 +248,6 @@ static struct ref_iterator_vtable merge_ref_iterator_vtable = {
 };
 
 struct ref_iterator *merge_ref_iterator_begin(
-		int ordered,
 		struct ref_iterator *iter0, struct ref_iterator *iter1,
 		ref_iterator_select_fn *select, void *cb_data)
 {
@@ -222,7 +262,7 @@ struct ref_iterator *merge_ref_iterator_begin(
 	 * references through only if they exist in both iterators.
 	 */
 
-	base_ref_iterator_init(ref_iterator, &merge_ref_iterator_vtable, ordered);
+	base_ref_iterator_init(ref_iterator, &merge_ref_iterator_vtable);
 	iter->iter0 = iter0;
 	iter->iter1 = iter1;
 	iter->select = select;
@@ -271,12 +311,9 @@ struct ref_iterator *overlay_ref_iterator_begin(
 	} else if (is_empty_ref_iterator(back)) {
 		ref_iterator_abort(back);
 		return front;
-	} else if (!front->ordered || !back->ordered) {
-		BUG("overlay_ref_iterator requires ordered inputs");
 	}
 
-	return merge_ref_iterator_begin(1, front, back,
-					overlay_iterator_select, NULL);
+	return merge_ref_iterator_begin(front, back, overlay_iterator_select, NULL);
 }
 
 struct prefix_ref_iterator {
@@ -315,16 +352,12 @@ static int prefix_ref_iterator_advance(struct ref_iterator *ref_iterator)
 
 		if (cmp > 0) {
 			/*
-			 * If the source iterator is ordered, then we
+			 * As the source iterator is ordered, we
 			 * can stop the iteration as soon as we see a
 			 * refname that comes after the prefix:
 			 */
-			if (iter->iter0->ordered) {
-				ok = ref_iterator_abort(iter->iter0);
-				break;
-			} else {
-				continue;
-			}
+			ok = ref_iterator_abort(iter->iter0);
+			break;
 		}
 
 		if (iter->trim) {
@@ -396,7 +429,7 @@ struct ref_iterator *prefix_ref_iterator_begin(struct ref_iterator *iter0,
 	CALLOC_ARRAY(iter, 1);
 	ref_iterator = &iter->base;
 
-	base_ref_iterator_init(ref_iterator, &prefix_ref_iterator_vtable, iter0->ordered);
+	base_ref_iterator_init(ref_iterator, &prefix_ref_iterator_vtable);
 
 	iter->iter0 = iter0;
 	iter->prefix = xstrdup(prefix);
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index a499a91c7e..4e826c05ff 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -1111,7 +1111,7 @@ static struct ref_iterator *packed_ref_iterator_begin(
 
 	CALLOC_ARRAY(iter, 1);
 	ref_iterator = &iter->base;
-	base_ref_iterator_init(ref_iterator, &packed_ref_iterator_vtable, 1);
+	base_ref_iterator_init(ref_iterator, &packed_ref_iterator_vtable);
 
 	if (exclude_patterns)
 		populate_excluded_jump_list(iter, snapshot, exclude_patterns);
diff --git a/refs/ref-cache.c b/refs/ref-cache.c
index a372a00941..9f9797209a 100644
--- a/refs/ref-cache.c
+++ b/refs/ref-cache.c
@@ -486,7 +486,7 @@ struct ref_iterator *cache_ref_iterator_begin(struct ref_cache *cache,
 
 	CALLOC_ARRAY(iter, 1);
 	ref_iterator = &iter->base;
-	base_ref_iterator_init(ref_iterator, &cache_ref_iterator_vtable, 1);
+	base_ref_iterator_init(ref_iterator, &cache_ref_iterator_vtable);
 	ALLOC_GROW(iter->levels, 10, iter->levels_alloc);
 
 	iter->levels_nr = 1;
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 83e0f0bba3..56641aa57a 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -260,6 +260,12 @@ enum do_for_each_ref_flags {
 	 * INCLUDE_BROKEN, since they are otherwise not included at all.
 	 */
 	DO_FOR_EACH_OMIT_DANGLING_SYMREFS = (1 << 2),
+
+	/*
+	 * Include root refs i.e. HEAD and pseudorefs along with the regular
+	 * refs.
+	 */
+	DO_FOR_EACH_INCLUDE_ROOT_REFS = (1 << 3),
 };
 
 /*
@@ -312,13 +318,6 @@ enum do_for_each_ref_flags {
  */
 struct ref_iterator {
 	struct ref_iterator_vtable *vtable;
-
-	/*
-	 * Does this `ref_iterator` iterate over references in order
-	 * by refname?
-	 */
-	unsigned int ordered : 1;
-
 	const char *refname;
 	const struct object_id *oid;
 	unsigned int flags;
@@ -386,15 +385,22 @@ typedef enum iterator_selection ref_iterator_select_fn(
 		struct ref_iterator *iter0, struct ref_iterator *iter1,
 		void *cb_data);
 
+/*
+ * An implementation of ref_iterator_select_fn that merges worktree and common
+ * refs. Per-worktree refs from the common iterator are ignored, worktree refs
+ * override common refs. Refs are selected lexicographically.
+ */
+enum iterator_selection ref_iterator_select(struct ref_iterator *iter_worktree,
+					    struct ref_iterator *iter_common,
+					    void *cb_data);
+
 /*
  * Iterate over the entries from iter0 and iter1, with the values
  * interleaved as directed by the select function. The iterator takes
  * ownership of iter0 and iter1 and frees them when the iteration is
- * over. A derived class should set `ordered` to 1 or 0 based on
- * whether it generates its output in order by reference name.
+ * over.
  */
 struct ref_iterator *merge_ref_iterator_begin(
-		int ordered,
 		struct ref_iterator *iter0, struct ref_iterator *iter1,
 		ref_iterator_select_fn *select, void *cb_data);
 
@@ -423,8 +429,6 @@ struct ref_iterator *overlay_ref_iterator_begin(
  * As an convenience to callers, if prefix is the empty string and
  * trim is zero, this function returns iter0 directly, without
  * wrapping it.
- *
- * The resulting ref_iterator is ordered if iter0 is.
  */
 struct ref_iterator *prefix_ref_iterator_begin(struct ref_iterator *iter0,
 					       const char *prefix,
@@ -435,14 +439,11 @@ struct ref_iterator *prefix_ref_iterator_begin(struct ref_iterator *iter0,
 /*
  * Base class constructor for ref_iterators. Initialize the
  * ref_iterator part of iter, setting its vtable pointer as specified.
- * `ordered` should be set to 1 if the iterator will iterate over
- * references in order by refname; otherwise it should be set to 0.
  * This is meant to be called only by the initializers of derived
  * classes.
  */
 void base_ref_iterator_init(struct ref_iterator *iter,
-			    struct ref_iterator_vtable *vtable,
-			    int ordered);
+			    struct ref_iterator_vtable *vtable);
 
 /*
  * Base class destructor for ref_iterators. Destroy the ref_iterator
diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
index 4d27fdde54..74dab18eda 100644
--- a/refs/reftable-backend.c
+++ b/refs/reftable-backend.c
@@ -365,12 +365,15 @@ static int reftable_ref_iterator_advance(struct ref_iterator *ref_iterator)
 			break;
 
 		/*
-		 * The files backend only lists references contained in
-		 * "refs/". We emulate the same behaviour here and thus skip
-		 * all references that don't start with this prefix.
+		 * The files backend only lists references contained in "refs/" unless
+		 * the root refs are to be included. We emulate the same behaviour here.
 		 */
-		if (!starts_with(iter->ref.refname, "refs/"))
+		if (!starts_with(iter->ref.refname, "refs/") &&
+		    !(iter->flags & DO_FOR_EACH_INCLUDE_ROOT_REFS &&
+		     (is_pseudoref(&iter->refs->base, iter->ref.refname) ||
+		      is_headref(&iter->refs->base, iter->ref.refname)))) {
 			continue;
+		}
 
 		if (iter->prefix_len &&
 		    strncmp(iter->prefix, iter->ref.refname, iter->prefix_len)) {
@@ -480,7 +483,7 @@ static struct reftable_ref_iterator *ref_iterator_for_stack(struct reftable_ref_
 	int ret;
 
 	iter = xcalloc(1, sizeof(*iter));
-	base_ref_iterator_init(&iter->base, &reftable_ref_iterator_vtable, 1);
+	base_ref_iterator_init(&iter->base, &reftable_ref_iterator_vtable);
 	iter->prefix = prefix;
 	iter->prefix_len = prefix ? strlen(prefix) : 0;
 	iter->base.oid = &iter->oid;
@@ -506,49 +509,6 @@ done:
 	return iter;
 }
 
-static enum iterator_selection iterator_select(struct ref_iterator *iter_worktree,
-					       struct ref_iterator *iter_common,
-					       void *cb_data UNUSED)
-{
-	if (iter_worktree && !iter_common) {
-		/*
-		 * Return the worktree ref if there are no more common refs.
-		 */
-		return ITER_SELECT_0;
-	} else if (iter_common) {
-		/*
-		 * In case we have pending worktree and common refs we need to
-		 * yield them based on their lexicographical order. Worktree
-		 * refs that have the same name as common refs shadow the
-		 * latter.
-		 */
-		if (iter_worktree) {
-			int cmp = strcmp(iter_worktree->refname,
-					 iter_common->refname);
-			if (cmp < 0)
-				return ITER_SELECT_0;
-			else if (!cmp)
-				return ITER_SELECT_0_SKIP_1;
-		}
-
-		 /*
-		  * We now know that the lexicographically-next ref is a common
-		  * ref. When the common ref is a shared one we return it.
-		  */
-		if (parse_worktree_ref(iter_common->refname, NULL, NULL,
-				       NULL) == REF_WORKTREE_SHARED)
-			return ITER_SELECT_1;
-
-		/*
-		 * Otherwise, if the common ref is a per-worktree ref we skip
-		 * it because it would belong to the main worktree, not ours.
-		 */
-		return ITER_SKIP_1;
-	} else {
-		return ITER_DONE;
-	}
-}
-
 static struct ref_iterator *reftable_be_iterator_begin(struct ref_store *ref_store,
 						       const char *prefix,
 						       const char **exclude_patterns,
@@ -577,8 +537,8 @@ static struct ref_iterator *reftable_be_iterator_begin(struct ref_store *ref_sto
 	 * single iterator.
 	 */
 	worktree_iter = ref_iterator_for_stack(refs, refs->worktree_stack, prefix, flags);
-	return merge_ref_iterator_begin(1, &worktree_iter->base, &main_iter->base,
-					iterator_select, NULL);
+	return merge_ref_iterator_begin(&worktree_iter->base, &main_iter->base,
+					ref_iterator_select, NULL);
 }
 
 static int reftable_be_read_raw_ref(struct ref_store *ref_store,
@@ -823,6 +783,7 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store,
 				      &head_referent, &head_type);
 	if (ret < 0)
 		goto done;
+	ret = 0;
 
 	for (i = 0; i < transaction->nr; i++) {
 		struct ref_update *u = transaction->updates[i];
@@ -1639,7 +1600,6 @@ struct reftable_reflog_iterator {
 	struct reftable_ref_store *refs;
 	struct reftable_iterator iter;
 	struct reftable_log_record log;
-	struct object_id oid;
 	char *last_name;
 	int err;
 };
@@ -1650,8 +1610,6 @@ static int reftable_reflog_iterator_advance(struct ref_iterator *ref_iterator)
 		(struct reftable_reflog_iterator *)ref_iterator;
 
 	while (!iter->err) {
-		int flags;
-
 		iter->err = reftable_iterator_next_log(&iter->iter, &iter->log);
 		if (iter->err)
 			break;
@@ -1664,17 +1622,13 @@ static int reftable_reflog_iterator_advance(struct ref_iterator *ref_iterator)
 		if (iter->last_name && !strcmp(iter->log.refname, iter->last_name))
 			continue;
 
-		if (!refs_resolve_ref_unsafe(&iter->refs->base, iter->log.refname,
-					     0, &iter->oid, &flags)) {
-			error(_("bad ref for %s"), iter->log.refname);
+		if (check_refname_format(iter->log.refname,
+					 REFNAME_ALLOW_ONELEVEL))
 			continue;
-		}
 
 		free(iter->last_name);
 		iter->last_name = xstrdup(iter->log.refname);
 		iter->base.refname = iter->log.refname;
-		iter->base.oid = &iter->oid;
-		iter->base.flags = flags;
 
 		break;
 	}
@@ -1725,9 +1679,8 @@ static struct reftable_reflog_iterator *reflog_iterator_for_stack(struct reftabl
 	int ret;
 
 	iter = xcalloc(1, sizeof(*iter));
-	base_ref_iterator_init(&iter->base, &reftable_reflog_iterator_vtable, 1);
+	base_ref_iterator_init(&iter->base, &reftable_reflog_iterator_vtable);
 	iter->refs = refs;
-	iter->base.oid = &iter->oid;
 
 	ret = refs->err;
 	if (ret)
@@ -1760,8 +1713,8 @@ static struct ref_iterator *reftable_be_reflog_iterator_begin(struct ref_store *
 
 	worktree_iter = reflog_iterator_for_stack(refs, refs->worktree_stack);
 
-	return merge_ref_iterator_begin(1, &worktree_iter->base, &main_iter->base,
-					iterator_select, NULL);
+	return merge_ref_iterator_begin(&worktree_iter->base, &main_iter->base,
+					ref_iterator_select, NULL);
 }
 
 static int yield_log_record(struct reftable_log_record *log,
diff --git a/remote.c b/remote.c
index 9090632e96..2b650b813b 100644
--- a/remote.c
+++ b/remote.c
@@ -2679,7 +2679,7 @@ static int is_reachable_in_reflog(const char *local, const struct ref *remote)
 		if (MERGE_BASES_BATCH_SIZE < size)
 			size = MERGE_BASES_BATCH_SIZE;
 
-		if ((ret = repo_in_merge_bases_many(the_repository, commit, size, chunk)))
+		if ((ret = repo_in_merge_bases_many(the_repository, commit, size, chunk, 0)))
 			break;
 	}
 
diff --git a/reset.c b/reset.c
index 0f2ff0fe31..d619cb7115 100644
--- a/reset.c
+++ b/reset.c
@@ -157,6 +157,11 @@ int reset_head(struct repository *r, const struct reset_head_opts *opts)
 	}
 
 	tree = parse_tree_indirect(oid);
+	if (!tree) {
+		ret = error(_("unable to read tree (%s)"), oid_to_hex(oid));
+		goto leave_reset_head;
+	}
+
 	prime_cache_tree(r, r->index, tree);
 
 	if (write_locked_index(r->index, &lock, COMMIT_LOCK) < 0) {
diff --git a/revision.c b/revision.c
index 2424c9bd67..45893651c2 100644
--- a/revision.c
+++ b/revision.c
@@ -381,13 +381,18 @@ static struct object *get_reference(struct rev_info *revs, const char *name,
 
 	object = parse_object_with_flags(revs->repo, oid,
 					 revs->verify_objects ? 0 :
-					 PARSE_OBJECT_SKIP_HASH_CHECK);
+					 PARSE_OBJECT_SKIP_HASH_CHECK |
+					 PARSE_OBJECT_DISCARD_TREE);
 
 	if (!object) {
 		if (revs->ignore_missing)
-			return object;
+			return NULL;
 		if (revs->exclude_promisor_objects && is_promisor_object(oid))
 			return NULL;
+		if (revs->do_not_die_on_missing_objects) {
+			oidset_insert(&revs->missing_commits, oid);
+			return NULL;
+		}
 		die("bad object %s", name);
 	}
 	object->flags |= flags;
@@ -415,15 +420,21 @@ static struct commit *handle_commit(struct rev_info *revs,
 	 */
 	while (object->type == OBJ_TAG) {
 		struct tag *tag = (struct tag *) object;
+		struct object_id *oid;
 		if (revs->tag_objects && !(flags & UNINTERESTING))
 			add_pending_object(revs, object, tag->tag);
-		object = parse_object(revs->repo, get_tagged_oid(tag));
+		oid = get_tagged_oid(tag);
+		object = parse_object(revs->repo, oid);
 		if (!object) {
 			if (revs->ignore_missing_links || (flags & UNINTERESTING))
 				return NULL;
 			if (revs->exclude_promisor_objects &&
 			    is_promisor_object(&tag->tagged->oid))
 				return NULL;
+			if (revs->do_not_die_on_missing_objects && oid) {
+				oidset_insert(&revs->missing_commits, oid);
+				return NULL;
+			}
 			die("bad object %s", oid_to_hex(&tag->tagged->oid));
 		}
 		object->flags |= flags;
@@ -1686,9 +1697,7 @@ static int handle_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
 	return 0;
 }
 
-static int handle_one_reflog(const char *refname_in_wt,
-			     const struct object_id *oid UNUSED,
-			     int flag UNUSED, void *cb_data)
+static int handle_one_reflog(const char *refname_in_wt, void *cb_data)
 {
 	struct all_refs_cb *cb = cb_data;
 	struct strbuf refname = STRBUF_INIT;
@@ -1947,6 +1956,7 @@ void repo_init_revisions(struct repository *r,
 	init_display_notes(&revs->notes_opt);
 	list_objects_filter_init(&revs->filter);
 	init_ref_exclusions(&revs->ref_excludes);
+	oidset_init(&revs->missing_commits, 0);
 }
 
 static void add_pending_commit_list(struct rev_info *revs,
@@ -1961,11 +1971,31 @@ static void add_pending_commit_list(struct rev_info *revs,
 	}
 }
 
+static const char *lookup_other_head(struct object_id *oid)
+{
+	int i;
+	static const char *const other_head[] = {
+		"MERGE_HEAD", "CHERRY_PICK_HEAD", "REVERT_HEAD", "REBASE_HEAD"
+	};
+
+	for (i = 0; i < ARRAY_SIZE(other_head); i++)
+		if (!read_ref_full(other_head[i],
+				RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
+				oid, NULL)) {
+			if (is_null_oid(oid))
+				die(_("%s exists but is a symbolic ref"), other_head[i]);
+			return other_head[i];
+		}
+
+	die(_("--merge requires one of the pseudorefs MERGE_HEAD, CHERRY_PICK_HEAD, REVERT_HEAD or REBASE_HEAD"));
+}
+
 static void prepare_show_merge(struct rev_info *revs)
 {
-	struct commit_list *bases;
+	struct commit_list *bases = NULL;
 	struct commit *head, *other;
 	struct object_id oid;
+	const char *other_name;
 	const char **prune = NULL;
 	int i, prune_num = 1; /* counting terminating NULL */
 	struct index_state *istate = revs->repo->index;
@@ -1973,12 +2003,12 @@ static void prepare_show_merge(struct rev_info *revs)
 	if (repo_get_oid(the_repository, "HEAD", &oid))
 		die("--merge without HEAD?");
 	head = lookup_commit_or_die(&oid, "HEAD");
-	if (repo_get_oid(the_repository, "MERGE_HEAD", &oid))
-		die("--merge without MERGE_HEAD?");
-	other = lookup_commit_or_die(&oid, "MERGE_HEAD");
+	other_name = lookup_other_head(&oid);
+	other = lookup_commit_or_die(&oid, other_name);
 	add_pending_object(revs, &head->object, "HEAD");
-	add_pending_object(revs, &other->object, "MERGE_HEAD");
-	bases = repo_get_merge_bases(the_repository, head, other);
+	add_pending_object(revs, &other->object, other_name);
+	if (repo_get_merge_bases(the_repository, head, other, &bases) < 0)
+		exit(128);
 	add_rev_cmdline_list(revs, bases, REV_CMD_MERGE_BASE, UNINTERESTING | BOTTOM);
 	add_pending_commit_list(revs, bases, UNINTERESTING | BOTTOM);
 	free_commit_list(bases);
@@ -2066,14 +2096,17 @@ static int handle_dotdot_1(const char *arg, char *dotdot,
 	} else {
 		/* A...B -- find merge bases between the two */
 		struct commit *a, *b;
-		struct commit_list *exclude;
+		struct commit_list *exclude = NULL;
 
 		a = lookup_commit_reference(revs->repo, &a_obj->oid);
 		b = lookup_commit_reference(revs->repo, &b_obj->oid);
 		if (!a || !b)
 			return dotdot_missing(arg, dotdot, revs, symmetric);
 
-		exclude = repo_get_merge_bases(the_repository, a, b);
+		if (repo_get_merge_bases(the_repository, a, b, &exclude) < 0) {
+			free_commit_list(exclude);
+			return -1;
+		}
 		add_rev_cmdline_list(revs, exclude, REV_CMD_MERGE_BASE,
 				     flags_exclude);
 		add_pending_commit_list(revs, exclude, flags_exclude);
@@ -2178,13 +2211,18 @@ static int handle_revision_arg_1(const char *arg_, struct rev_info *revs, int fl
 	if (revarg_opt & REVARG_COMMITTISH)
 		get_sha1_flags |= GET_OID_COMMITTISH;
 
+	/*
+	 * Even if revs->do_not_die_on_missing_objects is set, we
+	 * should error out if we can't even get an oid, as
+	 * `--missing=print` should be able to report missing oids.
+	 */
 	if (get_oid_with_context(revs->repo, arg, get_sha1_flags, &oid, &oc))
 		return revs->ignore_missing ? 0 : -1;
 	if (!cant_be_filename)
 		verify_non_filename(revs->prefix, arg);
 	object = get_reference(revs, arg, &oid, flags ^ local_flags);
 	if (!object)
-		return revs->ignore_missing ? 0 : -1;
+		return (revs->ignore_missing || revs->do_not_die_on_missing_objects) ? 0 : -1;
 	add_rev_cmdline(revs, object, arg_, REV_CMD_REV, flags ^ local_flags);
 	add_pending_object_with_path(revs, object, arg, oc.mode, oc.path);
 	free(oc.path);
@@ -3830,8 +3868,6 @@ int prepare_revision_walk(struct rev_info *revs)
 				       FOR_EACH_OBJECT_PROMISOR_ONLY);
 	}
 
-	oidset_init(&revs->missing_commits, 0);
-
 	if (!revs->reflog_info)
 		prepare_to_use_bloom_filter(revs);
 	if (!revs->unsorted_input)
diff --git a/sequencer.c b/sequencer.c
index f49a871ac0..5c6f541126 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -707,6 +707,8 @@ static int do_recursive_merge(struct repository *r,
 	o.show_rename_progress = 1;
 
 	head_tree = parse_tree_indirect(head);
+	if (!head_tree)
+		return error(_("unable to read tree (%s)"), oid_to_hex(head));
 	next_tree = next ? repo_get_commit_tree(r, next) : empty_tree(r);
 	base_tree = base ? repo_get_commit_tree(r, base) : empty_tree(r);
 
@@ -3882,6 +3884,8 @@ static int do_reset(struct repository *r,
 	}
 
 	tree = parse_tree_indirect(&oid);
+	if (!tree)
+		return error(_("unable to read tree (%s)"), oid_to_hex(&oid));
 	prime_cache_tree(r, r->index, tree);
 
 	if (write_locked_index(r->index, &lock, COMMIT_LOCK) < 0)
@@ -3908,7 +3912,7 @@ static int do_merge(struct repository *r,
 	int run_commit_flags = 0;
 	struct strbuf ref_name = STRBUF_INIT;
 	struct commit *head_commit, *merge_commit, *i;
-	struct commit_list *bases, *j;
+	struct commit_list *bases = NULL, *j;
 	struct commit_list *to_merge = NULL, **tail = &to_merge;
 	const char *strategy = !opts->xopts.nr &&
 		(!opts->strategy ||
@@ -4134,7 +4138,11 @@ static int do_merge(struct repository *r,
 	}
 
 	merge_commit = to_merge->item;
-	bases = repo_get_merge_bases(r, head_commit, merge_commit);
+	if (repo_get_merge_bases(r, head_commit, merge_commit, &bases) < 0) {
+		ret = -1;
+		goto leave_merge;
+	}
+
 	if (bases && oideq(&merge_commit->object.oid,
 			   &bases->item->object.oid)) {
 		ret = 0;
diff --git a/serve.c b/serve.c
index a1d71134d4..aa651b73e9 100644
--- a/serve.c
+++ b/serve.c
@@ -12,6 +12,7 @@
 #include "trace2.h"
 
 static int advertise_sid = -1;
+static int advertise_object_info = -1;
 static int client_hash_algo = GIT_HASH_SHA1;
 
 static int always_advertise(struct repository *r UNUSED,
@@ -67,6 +68,17 @@ static void session_id_receive(struct repository *r UNUSED,
 	trace2_data_string("transfer", NULL, "client-sid", client_sid);
 }
 
+static int object_info_advertise(struct repository *r, struct strbuf *value UNUSED)
+{
+	if (advertise_object_info == -1 &&
+	    repo_config_get_bool(r, "transfer.advertiseobjectinfo",
+				 &advertise_object_info)) {
+		/* disabled by default */
+		advertise_object_info = 0;
+	}
+	return advertise_object_info;
+}
+
 struct protocol_capability {
 	/*
 	 * The name of the capability.  The server uses this name when
@@ -135,7 +147,7 @@ static struct protocol_capability capabilities[] = {
 	},
 	{
 		.name = "object-info",
-		.advertise = always_advertise,
+		.advertise = object_info_advertise,
 		.command = cap_object_info,
 	},
 	{
diff --git a/setup.c b/setup.c
index b69b1cbc2a..e3b76e84b5 100644
--- a/setup.c
+++ b/setup.c
@@ -1889,6 +1889,13 @@ void initialize_repository_version(int hash_algo,
 	char repo_version_string[10];
 	int repo_version = GIT_REPO_VERSION;
 
+	/*
+	 * Note that we initialize the repository version to 1 when the ref
+	 * storage format is unknown. This is on purpose so that we can add the
+	 * correct object format to the config during git-clone(1). The format
+	 * version will get adjusted by git-clone(1) once it has learned about
+	 * the remote repository's format.
+	 */
 	if (hash_algo != GIT_HASH_SHA1 ||
 	    ref_storage_format != REF_STORAGE_FORMAT_FILES)
 		repo_version = GIT_REPO_VERSION_READ;
@@ -1898,7 +1905,7 @@ void initialize_repository_version(int hash_algo,
 		  "%d", repo_version);
 	git_config_set("core.repositoryformatversion", repo_version_string);
 
-	if (hash_algo != GIT_HASH_SHA1)
+	if (hash_algo != GIT_HASH_SHA1 && hash_algo != GIT_HASH_UNKNOWN)
 		git_config_set("extensions.objectformat",
 			       hash_algos[hash_algo].name);
 	else if (reinit)
diff --git a/shallow.c b/shallow.c
index 7711798127..7ff50dd0da 100644
--- a/shallow.c
+++ b/shallow.c
@@ -794,12 +794,16 @@ static void post_assign_shallow(struct shallow_info *info,
 		if (!*bitmap)
 			continue;
 		for (j = 0; j < bitmap_nr; j++)
-			if (bitmap[0][j] &&
-			    /* Step 7, reachability test at commit level */
-			    !repo_in_merge_bases_many(the_repository, c, ca.nr, ca.commits)) {
-				update_refstatus(ref_status, info->ref->nr, *bitmap);
-				dst++;
-				break;
+			if (bitmap[0][j]) {
+				/* Step 7, reachability test at commit level */
+				int ret = repo_in_merge_bases_many(the_repository, c, ca.nr, ca.commits, 1);
+				if (ret < 0)
+					exit(128);
+				if (!ret) {
+					update_refstatus(ref_status, info->ref->nr, *bitmap);
+					dst++;
+					break;
+				}
 			}
 	}
 	info->nr_ours = dst;
@@ -827,7 +831,10 @@ int delayed_reachability_test(struct shallow_info *si, int c)
 		si->reachable[c] = repo_in_merge_bases_many(the_repository,
 							    commit,
 							    si->nr_commits,
-							    si->commits);
+							    si->commits,
+							    1);
+		if (si->reachable[c] < 0)
+			exit(128);
 		si->need_reachability_test[c] = 0;
 	}
 	return si->reachable[c];
diff --git a/submodule.c b/submodule.c
index 213da79f66..f0ddb31e8f 100644
--- a/submodule.c
+++ b/submodule.c
@@ -592,7 +592,12 @@ static void show_submodule_header(struct diff_options *o,
 	     (!is_null_oid(two) && !*right))
 		message = "(commits not present)";
 
-	*merge_bases = repo_get_merge_bases(sub, *left, *right);
+	*merge_bases = NULL;
+	if (repo_get_merge_bases(sub, *left, *right, merge_bases) < 0) {
+		message = "(corrupt repository)";
+		goto output_header;
+	}
+
 	if (*merge_bases) {
 		if ((*merge_bases)->item == *left)
 			fast_forward = 1;
@@ -1687,8 +1692,6 @@ static int get_next_submodule(struct child_process *cp, struct strbuf *err,
 		task = get_fetch_task_from_changed(spf, err);
 
 	if (task) {
-		struct strbuf submodule_prefix = STRBUF_INIT;
-
 		child_process_init(cp);
 		cp->dir = task->repo->gitdir;
 		prepare_submodule_repo_env_in_gitdir(&cp->env);
@@ -1698,15 +1701,11 @@ static int get_next_submodule(struct child_process *cp, struct strbuf *err,
 			strvec_pushv(&cp->args, task->git_args.v);
 		strvec_pushv(&cp->args, spf->args.v);
 		strvec_push(&cp->args, task->default_argv);
-		strvec_push(&cp->args, "--submodule-prefix");
+		strvec_pushf(&cp->args, "--submodule-prefix=%s%s/",
+			     spf->prefix, task->sub->path);
 
-		strbuf_addf(&submodule_prefix, "%s%s/",
-						spf->prefix,
-						task->sub->path);
-		strvec_push(&cp->args, submodule_prefix.buf);
 		*task_cb = task;
 
-		strbuf_release(&submodule_prefix);
 		string_list_insert(&spf->seen_submodule_names, task->sub->name);
 		return 1;
 	}
@@ -1714,12 +1713,8 @@ static int get_next_submodule(struct child_process *cp, struct strbuf *err,
 	if (spf->oid_fetch_tasks_nr) {
 		struct fetch_task *task =
 			spf->oid_fetch_tasks[spf->oid_fetch_tasks_nr - 1];
-		struct strbuf submodule_prefix = STRBUF_INIT;
 		spf->oid_fetch_tasks_nr--;
 
-		strbuf_addf(&submodule_prefix, "%s%s/",
-			    spf->prefix, task->sub->path);
-
 		child_process_init(cp);
 		prepare_submodule_repo_env_in_gitdir(&cp->env);
 		cp->git_cmd = 1;
@@ -1728,8 +1723,8 @@ static int get_next_submodule(struct child_process *cp, struct strbuf *err,
 		strvec_init(&cp->args);
 		strvec_pushv(&cp->args, spf->args.v);
 		strvec_push(&cp->args, "on-demand");
-		strvec_push(&cp->args, "--submodule-prefix");
-		strvec_push(&cp->args, submodule_prefix.buf);
+		strvec_pushf(&cp->args, "--submodule-prefix=%s%s/",
+			     spf->prefix, task->sub->path);
 
 		/* NEEDSWORK: have get_default_remote from submodule--helper */
 		strvec_push(&cp->args, "origin");
@@ -1737,7 +1732,6 @@ static int get_next_submodule(struct child_process *cp, struct strbuf *err,
 					  append_oid_to_argv, &cp->args);
 
 		*task_cb = task;
-		strbuf_release(&submodule_prefix);
 		return 1;
 	}
 
diff --git a/t/helper/test-reach.c b/t/helper/test-reach.c
index 1e159a754d..1e3b431e3e 100644
--- a/t/helper/test-reach.c
+++ b/t/helper/test-reach.c
@@ -111,13 +111,16 @@ int cmd__reach(int ac, const char **av)
 		       repo_in_merge_bases(the_repository, A, B));
 	else if (!strcmp(av[1], "in_merge_bases_many"))
 		printf("%s(A,X):%d\n", av[1],
-		       repo_in_merge_bases_many(the_repository, A, X_nr, X_array));
+		       repo_in_merge_bases_many(the_repository, A, X_nr, X_array, 0));
 	else if (!strcmp(av[1], "is_descendant_of"))
 		printf("%s(A,X):%d\n", av[1], repo_is_descendant_of(r, A, X));
 	else if (!strcmp(av[1], "get_merge_bases_many")) {
-		struct commit_list *list = repo_get_merge_bases_many(the_repository,
-								     A, X_nr,
-								     X_array);
+		struct commit_list *list = NULL;
+		if (repo_get_merge_bases_many(the_repository,
+					      A, X_nr,
+					      X_array,
+					      &list) < 0)
+			exit(128);
 		printf("%s(A,X):\n", av[1]);
 		print_sorted_commit_ids(list);
 	} else if (!strcmp(av[1], "reduce_heads")) {
diff --git a/t/helper/test-ref-store.c b/t/helper/test-ref-store.c
index 702ec1f128..7a0f6cac53 100644
--- a/t/helper/test-ref-store.c
+++ b/t/helper/test-ref-store.c
@@ -221,15 +221,21 @@ static int cmd_verify_ref(struct ref_store *refs, const char **argv)
 	return ret;
 }
 
+static int each_reflog(const char *refname, void *cb_data UNUSED)
+{
+	printf("%s\n", refname);
+	return 0;
+}
+
 static int cmd_for_each_reflog(struct ref_store *refs,
 			       const char **argv UNUSED)
 {
-	return refs_for_each_reflog(refs, each_ref, NULL);
+	return refs_for_each_reflog(refs, each_reflog, NULL);
 }
 
-static int each_reflog(struct object_id *old_oid, struct object_id *new_oid,
-		       const char *committer, timestamp_t timestamp,
-		       int tz, const char *msg, void *cb_data UNUSED)
+static int each_reflog_ent(struct object_id *old_oid, struct object_id *new_oid,
+			   const char *committer, timestamp_t timestamp,
+			   int tz, const char *msg, void *cb_data UNUSED)
 {
 	printf("%s %s %s %" PRItime " %+05d%s%s", oid_to_hex(old_oid),
 	       oid_to_hex(new_oid), committer, timestamp, tz,
@@ -241,14 +247,14 @@ static int cmd_for_each_reflog_ent(struct ref_store *refs, const char **argv)
 {
 	const char *refname = notnull(*argv++, "refname");
 
-	return refs_for_each_reflog_ent(refs, refname, each_reflog, refs);
+	return refs_for_each_reflog_ent(refs, refname, each_reflog_ent, refs);
 }
 
 static int cmd_for_each_reflog_ent_reverse(struct ref_store *refs, const char **argv)
 {
 	const char *refname = notnull(*argv++, "refname");
 
-	return refs_for_each_reflog_ent_reverse(refs, refname, each_reflog, refs);
+	return refs_for_each_reflog_ent_reverse(refs, refname, each_reflog_ent, refs);
 }
 
 static int cmd_reflog_exists(struct ref_store *refs, const char **argv)
diff --git a/t/lib-credential.sh b/t/lib-credential.sh
index 15fc9a31e2..44799c0d38 100644
--- a/t/lib-credential.sh
+++ b/t/lib-credential.sh
@@ -50,6 +50,7 @@ helper_test_clean() {
 	reject $1 https example.com user-overwrite
 	reject $1 https example.com user-erase1
 	reject $1 https example.com user-erase2
+	reject $1 https victim.example.com user
 	reject $1 http path.tld user
 	reject $1 https timeout.tld user
 	reject $1 https sso.tld
diff --git a/t/t0303-credential-external.sh b/t/t0303-credential-external.sh
index 095574bfc6..72ae405c3e 100755
--- a/t/t0303-credential-external.sh
+++ b/t/t0303-credential-external.sh
@@ -32,9 +32,24 @@ commands.
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-credential.sh
 
+# If we're not given a specific external helper to run against,
+# there isn't much to test. But we can still run through our
+# battery of tests with a fake helper and check that the
+# test themselves are self-consistent and clean up after
+# themselves.
+#
+# We'll use the "store" helper, since we can easily inspect
+# its state by looking at the on-disk file. But since it doesn't
+# implement any caching or expiry logic, we'll cheat and override
+# the "check" function to just report all results as OK.
 if test -z "$GIT_TEST_CREDENTIAL_HELPER"; then
-	skip_all="used to test external credential helpers"
-	test_done
+	GIT_TEST_CREDENTIAL_HELPER=store
+	GIT_TEST_CREDENTIAL_HELPER_TIMEOUT=store
+	check () {
+		test "$1" = "approve" || return 0
+		git -c credential.helper=store credential approve
+	}
+	check_cleanup=t
 fi
 
 test -z "$GIT_TEST_CREDENTIAL_HELPER_SETUP" ||
@@ -59,4 +74,11 @@ fi
 # might be long-term system storage
 helper_test_clean "$GIT_TEST_CREDENTIAL_HELPER"
 
+if test "$check_cleanup" = "t"
+then
+	test_expect_success 'test cleanup removes everything' '
+		test_must_be_empty "$HOME/.git-credentials"
+	'
+fi
+
 test_done
diff --git a/t/t0410-partial-clone.sh b/t/t0410-partial-clone.sh
index 0f98b21be8..88a66f0904 100755
--- a/t/t0410-partial-clone.sh
+++ b/t/t0410-partial-clone.sh
@@ -665,6 +665,21 @@ test_expect_success 'lazy-fetch when accessing object not in the_repository' '
 	git -C partial.git rev-list --objects --missing=print HEAD >out &&
 	grep "[?]$FILE_HASH" out &&
 
+	# The no-lazy-fetch mechanism prevents Git from fetching
+	test_must_fail env GIT_NO_LAZY_FETCH=1 \
+		git -C partial.git cat-file -e "$FILE_HASH" &&
+
+	# The same with command line option to "git"
+	test_must_fail git --no-lazy-fetch -C partial.git cat-file -e "$FILE_HASH" &&
+
+	# The same, forcing a subprocess via an alias
+	test_must_fail git --no-lazy-fetch -C partial.git \
+		-c alias.foo="!git cat-file" foo -e "$FILE_HASH" &&
+
+	# Sanity check that the file is still missing
+	git -C partial.git rev-list --objects --missing=print HEAD >out &&
+	grep "[?]$FILE_HASH" out &&
+
 	git -C full cat-file -s "$FILE_HASH" >expect &&
 	test-tool partial-clone object-info partial.git "$FILE_HASH" >actual &&
 	test_cmp expect actual &&
diff --git a/t/t0600-reffiles-backend.sh b/t/t0600-reffiles-backend.sh
index 485481d6b4..64214340e7 100755
--- a/t/t0600-reffiles-backend.sh
+++ b/t/t0600-reffiles-backend.sh
@@ -279,31 +279,31 @@ test_expect_success 'setup worktree' '
 # direct FS access for creating the reflogs. 3) PSEUDO-WT and refs/bisect/random
 # do not create reflogs by default, so it is not testing a realistic scenario.
 test_expect_success 'for_each_reflog()' '
-	echo $ZERO_OID > .git/logs/PSEUDO-MAIN &&
+	echo $ZERO_OID >.git/logs/PSEUDO_MAIN_HEAD &&
 	mkdir -p     .git/logs/refs/bisect &&
-	echo $ZERO_OID > .git/logs/refs/bisect/random &&
+	echo $ZERO_OID >.git/logs/refs/bisect/random &&
 
-	echo $ZERO_OID > .git/worktrees/wt/logs/PSEUDO-WT &&
+	echo $ZERO_OID >.git/worktrees/wt/logs/PSEUDO_WT_HEAD &&
 	mkdir -p     .git/worktrees/wt/logs/refs/bisect &&
-	echo $ZERO_OID > .git/worktrees/wt/logs/refs/bisect/wt-random &&
+	echo $ZERO_OID >.git/worktrees/wt/logs/refs/bisect/wt-random &&
 
-	$RWT for-each-reflog | cut -d" " -f 2- | sort >actual &&
+	$RWT for-each-reflog >actual &&
 	cat >expected <<-\EOF &&
-	HEAD 0x1
-	PSEUDO-WT 0x0
-	refs/bisect/wt-random 0x0
-	refs/heads/main 0x0
-	refs/heads/wt-main 0x0
+	HEAD
+	PSEUDO_WT_HEAD
+	refs/bisect/wt-random
+	refs/heads/main
+	refs/heads/wt-main
 	EOF
 	test_cmp expected actual &&
 
-	$RMAIN for-each-reflog | cut -d" " -f 2- | sort >actual &&
+	$RMAIN for-each-reflog >actual &&
 	cat >expected <<-\EOF &&
-	HEAD 0x1
-	PSEUDO-MAIN 0x0
-	refs/bisect/random 0x0
-	refs/heads/main 0x0
-	refs/heads/wt-main 0x0
+	HEAD
+	PSEUDO_MAIN_HEAD
+	refs/bisect/random
+	refs/heads/main
+	refs/heads/wt-main
 	EOF
 	test_cmp expected actual
 '
diff --git a/t/t0610-reftable-basics.sh b/t/t0610-reftable-basics.sh
index 6a131e40b8..686781192e 100755
--- a/t/t0610-reftable-basics.sh
+++ b/t/t0610-reftable-basics.sh
@@ -328,6 +328,18 @@ test_expect_success 'ref transaction: writes are synced' '
 	EOF
 '
 
+test_expect_success 'ref transaction: empty transaction in empty repo' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	test_commit -C repo --no-tag A &&
+	git -C repo update-ref -d refs/heads/main &&
+	test-tool -C repo ref-store main delete-refs REF_NO_DEREF msg HEAD &&
+	git -C repo update-ref --stdin <<-EOF
+	prepare
+	commit
+	EOF
+'
+
 test_expect_success 'pack-refs: compacts tables' '
 	test_when_finished "rm -rf repo" &&
 	git init repo &&
diff --git a/t/t1405-main-ref-store.sh b/t/t1405-main-ref-store.sh
index 1183232a72..a6bcd62ab6 100755
--- a/t/t1405-main-ref-store.sh
+++ b/t/t1405-main-ref-store.sh
@@ -68,11 +68,11 @@ test_expect_success 'verify_ref(new-main)' '
 '
 
 test_expect_success 'for_each_reflog()' '
-	$RUN for-each-reflog | sort -k2 | cut -d" " -f 2- >actual &&
+	$RUN for-each-reflog >actual &&
 	cat >expected <<-\EOF &&
-	HEAD 0x1
-	refs/heads/main 0x0
-	refs/heads/new-main 0x0
+	HEAD
+	refs/heads/main
+	refs/heads/new-main
 	EOF
 	test_cmp expected actual
 '
diff --git a/t/t1406-submodule-ref-store.sh b/t/t1406-submodule-ref-store.sh
index e6a7f7334b..c01f0f14a1 100755
--- a/t/t1406-submodule-ref-store.sh
+++ b/t/t1406-submodule-ref-store.sh
@@ -63,11 +63,11 @@ test_expect_success 'verify_ref(new-main)' '
 '
 
 test_expect_success 'for_each_reflog()' '
-	$RUN for-each-reflog | sort | cut -d" " -f 2- >actual &&
+	$RUN for-each-reflog >actual &&
 	cat >expected <<-\EOF &&
-	HEAD 0x1
-	refs/heads/main 0x0
-	refs/heads/new-main 0x0
+	HEAD
+	refs/heads/main
+	refs/heads/new-main
 	EOF
 	test_cmp expected actual
 '
diff --git a/t/t1410-reflog.sh b/t/t1410-reflog.sh
index d2f5f42e67..5bf883f1e3 100755
--- a/t/t1410-reflog.sh
+++ b/t/t1410-reflog.sh
@@ -436,4 +436,112 @@ test_expect_success 'empty reflog' '
 	test_must_be_empty err
 '
 
+test_expect_success 'list reflogs' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		git reflog list >actual &&
+		test_must_be_empty actual &&
+
+		test_commit A &&
+		cat >expect <<-EOF &&
+		HEAD
+		refs/heads/main
+		EOF
+		git reflog list >actual &&
+		test_cmp expect actual &&
+
+		git branch b &&
+		cat >expect <<-EOF &&
+		HEAD
+		refs/heads/b
+		refs/heads/main
+		EOF
+		git reflog list >actual &&
+		test_cmp expect actual
+	)
+'
+
+test_expect_success 'list reflogs with worktree' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+
+		test_commit A &&
+		git worktree add wt &&
+		git -c core.logAllRefUpdates=always \
+			update-ref refs/worktree/main HEAD &&
+		git -c core.logAllRefUpdates=always \
+			update-ref refs/worktree/per-worktree HEAD &&
+		git -c core.logAllRefUpdates=always -C wt \
+			update-ref refs/worktree/per-worktree HEAD &&
+		git -c core.logAllRefUpdates=always -C wt \
+			update-ref refs/worktree/worktree HEAD &&
+
+		cat >expect <<-EOF &&
+		HEAD
+		refs/heads/main
+		refs/heads/wt
+		refs/worktree/main
+		refs/worktree/per-worktree
+		EOF
+		git reflog list >actual &&
+		test_cmp expect actual &&
+
+		cat >expect <<-EOF &&
+		HEAD
+		refs/heads/main
+		refs/heads/wt
+		refs/worktree/per-worktree
+		refs/worktree/worktree
+		EOF
+		git -C wt reflog list >actual &&
+		test_cmp expect actual
+	)
+'
+
+test_expect_success 'reflog list returns error with additional args' '
+	cat >expect <<-EOF &&
+	error: list does not accept arguments: ${SQ}bogus${SQ}
+	EOF
+	test_must_fail git reflog list bogus 2>err &&
+	test_cmp expect err
+'
+
+test_expect_success 'reflog for symref with unborn target can be listed' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit A &&
+		git symbolic-ref HEAD refs/heads/unborn &&
+		cat >expect <<-EOF &&
+		HEAD
+		refs/heads/main
+		EOF
+		git reflog list >actual &&
+		test_cmp expect actual
+	)
+'
+
+test_expect_success 'reflog with invalid object ID can be listed' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit A &&
+		test-tool ref-store main update-ref msg refs/heads/missing \
+			$(test_oid deadbeef) "$ZERO_OID" REF_SKIP_OID_VERIFICATION &&
+		cat >expect <<-EOF &&
+		HEAD
+		refs/heads/main
+		refs/heads/missing
+		EOF
+		git reflog list >actual &&
+		test_cmp expect actual
+	)
+'
+
 test_done
diff --git a/t/t3202-show-branch.sh b/t/t3202-show-branch.sh
index 6a98b2df76..a1139f79e2 100755
--- a/t/t3202-show-branch.sh
+++ b/t/t3202-show-branch.sh
@@ -4,9 +4,6 @@ test_description='test show-branch'
 
 . ./test-lib.sh
 
-# arbitrary reference time: 2009-08-30 19:20:00
-GIT_TEST_DATE_NOW=1251660000; export GIT_TEST_DATE_NOW
-
 test_expect_success 'error descriptions on empty repository' '
 	current=$(git branch --show-current) &&
 	cat >expect <<-EOF &&
@@ -187,18 +184,6 @@ test_expect_success 'show branch --merge-base with N arguments' '
 	test_cmp expect actual
 '
 
-test_expect_success 'show branch --reflog=2' '
-	sed "s/^>	//" >expect <<-\EOF &&
-	>	! [refs/heads/branch10@{0}] (4 years, 5 months ago) commit: branch10
-	>	 ! [refs/heads/branch10@{1}] (4 years, 5 months ago) commit: branch10
-	>	--
-	>	+  [refs/heads/branch10@{0}] branch10
-	>	++ [refs/heads/branch10@{1}] initial
-	EOF
-	git show-branch --reflog=2 >actual &&
-	test_cmp actual expect
-'
-
 # incompatible options
 while read combo
 do
@@ -264,4 +249,38 @@ test_expect_success 'error descriptions on orphan branch' '
 	test_branch_op_in_wt -c new-branch
 '
 
+test_expect_success 'setup reflogs' '
+	test_commit base &&
+	git checkout -b branch &&
+	test_commit one &&
+	git reset --hard HEAD^ &&
+	test_commit two &&
+	test_commit three
+'
+
+test_expect_success '--reflog shows reflog entries' '
+	cat >expect <<-\EOF &&
+	! [branch@{0}] (0 seconds ago) commit: three
+	 ! [branch@{1}] (60 seconds ago) commit: two
+	  ! [branch@{2}] (2 minutes ago) reset: moving to HEAD^
+	   ! [branch@{3}] (2 minutes ago) commit: one
+	----
+	+    [branch@{0}] three
+	++   [branch@{1}] two
+	   + [branch@{3}] one
+	++++ [branch@{2}] base
+	EOF
+	# the output always contains relative timestamps; use
+	# a known time to get deterministic results
+	GIT_TEST_DATE_NOW=$test_tick \
+	git show-branch --reflog branch >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success '--reflog handles missing reflog' '
+	git reflog expire --expire=now branch &&
+	git show-branch --reflog branch >actual &&
+	test_must_be_empty actual
+'
+
 test_done
diff --git a/t/t4042-diff-textconv-caching.sh b/t/t4042-diff-textconv-caching.sh
index bf33aedf4b..8ebfa3c1be 100755
--- a/t/t4042-diff-textconv-caching.sh
+++ b/t/t4042-diff-textconv-caching.sh
@@ -118,4 +118,26 @@ test_expect_success 'log notes cache and still use cache for -p' '
 	git log --no-walk -p refs/notes/textconv/magic HEAD
 '
 
+test_expect_success 'caching is silently ignored outside repo' '
+	mkdir -p non-repo &&
+	echo one >non-repo/one &&
+	echo two >non-repo/two &&
+	echo "* diff=test" >attr &&
+	test_expect_code 1 \
+	nongit git -c core.attributesFile="$PWD/attr" \
+		   -c diff.test.textconv="tr a-z A-Z <" \
+		   -c diff.test.cachetextconv=true \
+		   diff --no-index one two >actual &&
+	cat >expect <<-\EOF &&
+	diff --git a/one b/two
+	index 5626abf..f719efd 100644
+	--- a/one
+	+++ b/two
+	@@ -1 +1 @@
+	-ONE
+	+TWO
+	EOF
+	test_cmp expect actual
+'
+
 test_done
diff --git a/t/t4301-merge-tree-write-tree.sh b/t/t4301-merge-tree-write-tree.sh
index 12ac436873..29e9974cdf 100755
--- a/t/t4301-merge-tree-write-tree.sh
+++ b/t/t4301-merge-tree-write-tree.sh
@@ -945,4 +945,49 @@ test_expect_success 'check the input format when --stdin is passed' '
 	test_cmp expect actual
 '
 
+test_expect_success '--merge-base with tree OIDs' '
+	git merge-tree --merge-base=side1^ side1 side3 >with-commits &&
+	git merge-tree --merge-base=side1^^{tree} side1^{tree} side3^{tree} >with-trees &&
+	test_cmp with-commits with-trees
+'
+
+test_expect_success 'error out on missing tree objects' '
+	git init --bare missing-tree.git &&
+	git rev-list side3 >list &&
+	git rev-parse side3^: >>list &&
+	git pack-objects missing-tree.git/objects/pack/side3-tree-is-missing <list &&
+	side3=$(git rev-parse side3) &&
+	test_must_fail git --git-dir=missing-tree.git merge-tree $side3^ $side3 >actual 2>err &&
+	test_grep "Could not read $(git rev-parse $side3:)" err &&
+	test_must_be_empty actual
+'
+
+test_expect_success 'error out on missing blob objects' '
+	echo 1 | git hash-object -w --stdin >blob1 &&
+	echo 2 | git hash-object -w --stdin >blob2 &&
+	echo 3 | git hash-object -w --stdin >blob3 &&
+	printf "100644 blob $(cat blob1)\tblob\n" | git mktree >tree1 &&
+	printf "100644 blob $(cat blob2)\tblob\n" | git mktree >tree2 &&
+	printf "100644 blob $(cat blob3)\tblob\n" | git mktree >tree3 &&
+	git init --bare missing-blob.git &&
+	cat blob1 blob3 tree1 tree2 tree3 |
+	git pack-objects missing-blob.git/objects/pack/side1-whatever-is-missing &&
+	test_must_fail git --git-dir=missing-blob.git >actual 2>err \
+		merge-tree --merge-base=$(cat tree1) $(cat tree2) $(cat tree3) &&
+	test_grep "unable to read blob object $(cat blob2)" err &&
+	test_must_be_empty actual
+'
+
+test_expect_success 'error out on missing commits as well' '
+	git init --bare missing-commit.git &&
+	git rev-list --objects side1 side3 >list-including-initial &&
+	grep -v ^$(git rev-parse side1^) <list-including-initial >list &&
+	git pack-objects missing-commit.git/objects/pack/missing-initial <list &&
+	side1=$(git rev-parse side1) &&
+	side3=$(git rev-parse side3) &&
+	test_must_fail git --git-dir=missing-commit.git \
+		merge-tree --allow-unrelated-histories $side1 $side3 >actual &&
+	test_must_be_empty actual
+'
+
 test_done
diff --git a/t/t5555-http-smart-common.sh b/t/t5555-http-smart-common.sh
index b1cfe8b7db..3dcb3340a3 100755
--- a/t/t5555-http-smart-common.sh
+++ b/t/t5555-http-smart-common.sh
@@ -131,7 +131,6 @@ test_expect_success 'git upload-pack --advertise-refs: v2' '
 	fetch=shallow wait-for-done
 	server-option
 	object-format=$(test_oid algo)
-	object-info
 	0000
 	EOF
 
diff --git a/t/t5701-git-serve.sh b/t/t5701-git-serve.sh
index 3591bc2417..c48830de8f 100755
--- a/t/t5701-git-serve.sh
+++ b/t/t5701-git-serve.sh
@@ -20,7 +20,6 @@ test_expect_success 'test capability advertisement' '
 	fetch=shallow wait-for-done
 	server-option
 	object-format=$(test_oid algo)
-	object-info
 	EOF
 	cat >expect.trailer <<-EOF &&
 	0000
@@ -323,6 +322,8 @@ test_expect_success 'unexpected lines are not allowed in fetch request' '
 # Test the basics of object-info
 #
 test_expect_success 'basics of object-info' '
+	test_config transfer.advertiseObjectInfo true &&
+
 	test-tool pkt-line pack >in <<-EOF &&
 	command=object-info
 	object-format=$(test_oid algo)
@@ -380,4 +381,25 @@ test_expect_success 'basics of bundle-uri: dies if not enabled' '
 	test_must_be_empty out
 '
 
+test_expect_success 'object-info missing from capabilities when disabled' '
+	test_config transfer.advertiseObjectInfo false &&
+
+	GIT_TEST_SIDEBAND_ALL=0 test-tool serve-v2 \
+		--advertise-capabilities >out &&
+	test-tool pkt-line unpack <out >actual &&
+
+	! grep object.info actual
+'
+
+test_expect_success 'object-info commands rejected when disabled' '
+	test_config transfer.advertiseObjectInfo false &&
+
+	test-tool pkt-line pack >in <<-EOF &&
+	command=object-info
+	EOF
+
+	test_must_fail test-tool serve-v2 --stateless-rpc <in 2>err &&
+	grep invalid.command err
+'
+
 test_done
diff --git a/t/t5702-protocol-v2.sh b/t/t5702-protocol-v2.sh
index 6ef4971845..1ef540f73d 100755
--- a/t/t5702-protocol-v2.sh
+++ b/t/t5702-protocol-v2.sh
@@ -778,6 +778,25 @@ test_expect_success 'archive with custom path does not request v2' '
 	! grep ^GIT_PROTOCOL env.trace
 '
 
+test_expect_success 'reject client packfile-uris if not advertised' '
+	{
+		packetize command=fetch &&
+		packetize object-format=$(test_oid algo) &&
+		printf 0001 &&
+		packetize packfile-uris https &&
+		packetize done &&
+		printf 0000
+	} >input &&
+	test_must_fail env GIT_PROTOCOL=version=2 \
+		git upload-pack client <input &&
+	test_must_fail env GIT_PROTOCOL=version=2 \
+		git -c uploadpack.blobpackfileuri \
+		upload-pack client <input &&
+	GIT_PROTOCOL=version=2 \
+		git -c uploadpack.blobpackfileuri=anything \
+		upload-pack client <input
+'
+
 # Test protocol v2 with 'http://' transport
 #
 . "$TEST_DIRECTORY"/lib-httpd.sh
diff --git a/t/t5801/git-remote-testgit b/t/t5801/git-remote-testgit
index 1544d6dc6b..bcfb358c51 100755
--- a/t/t5801/git-remote-testgit
+++ b/t/t5801/git-remote-testgit
@@ -12,6 +12,11 @@ url=$2
 
 dir="$GIT_DIR/testgit/$alias"
 
+if ! git rev-parse --is-inside-git-dir
+then
+	exit 1
+fi
+
 h_refspec="refs/heads/*:refs/testgit/$alias/heads/*"
 t_refspec="refs/tags/*:refs/testgit/$alias/tags/*"
 
diff --git a/t/t6022-rev-list-missing.sh b/t/t6022-rev-list-missing.sh
index 211672759a..127180e1c9 100755
--- a/t/t6022-rev-list-missing.sh
+++ b/t/t6022-rev-list-missing.sh
@@ -10,7 +10,10 @@ TEST_PASSES_SANITIZE_LEAK=true
 test_expect_success 'create repository and alternate directory' '
 	test_commit 1 &&
 	test_commit 2 &&
-	test_commit 3
+	test_commit 3 &&
+	git tag -m "tag message" annot_tag HEAD~1 &&
+	git tag regul_tag HEAD~1 &&
+	git branch a_branch HEAD~1
 '
 
 # We manually corrupt the repository, which means that the commit-graph may
@@ -46,9 +49,10 @@ do
 			git rev-list --objects --no-object-names \
 				HEAD ^$obj >expect.raw &&
 
-			# Blobs are shared by all commits, so evethough a commit/tree
+			# Blobs are shared by all commits, so even though a commit/tree
 			# might be skipped, its blob must be accounted for.
-			if [ $obj != "HEAD:1.t" ]; then
+			if test $obj != "HEAD:1.t"
+			then
 				echo $(git rev-parse HEAD:1.t) >>expect.raw &&
 				echo $(git rev-parse HEAD:2.t) >>expect.raw
 			fi &&
@@ -77,4 +81,69 @@ do
 	done
 done
 
+for missing_tip in "annot_tag" "regul_tag" "a_branch" "HEAD~1" "HEAD~1^{tree}" "HEAD:1.t"
+do
+	# We want to check that things work when both
+	#   - all the tips passed are missing (case existing_tip = ""), and
+	#   - there is one missing tip and one existing tip (case existing_tip = "HEAD")
+	for existing_tip in "" "HEAD"
+	do
+		for action in "allow-any" "print"
+		do
+			test_expect_success "--missing=$action with tip '$missing_tip' missing and tip '$existing_tip'" '
+				# Before the object is made missing, we use rev-list to
+				# get the expected oids.
+				if test "$existing_tip" = "HEAD"
+				then
+					git rev-list --objects --no-object-names \
+						HEAD ^$missing_tip >expect.raw
+				else
+					>expect.raw
+				fi &&
+
+				# Blobs are shared by all commits, so even though a commit/tree
+				# might be skipped, its blob must be accounted for.
+				if test "$existing_tip" = "HEAD" && test $missing_tip != "HEAD:1.t"
+				then
+					echo $(git rev-parse HEAD:1.t) >>expect.raw &&
+					echo $(git rev-parse HEAD:2.t) >>expect.raw
+				fi &&
+
+				missing_oid="$(git rev-parse $missing_tip)" &&
+
+				if test "$missing_tip" = "annot_tag"
+				then
+					oid="$(git rev-parse $missing_tip^{commit})" &&
+					echo "$missing_oid" >>expect.raw
+				else
+					oid="$missing_oid"
+				fi &&
+
+				path=".git/objects/$(test_oid_to_path $oid)" &&
+
+				mv "$path" "$path.hidden" &&
+				test_when_finished "mv $path.hidden $path" &&
+
+				git rev-list --missing=$action --objects --no-object-names \
+				     $missing_oid $existing_tip >actual.raw &&
+
+				# When the action is to print, we should also add the missing
+				# oid to the expect list.
+				case $action in
+				allow-any)
+					;;
+				print)
+					grep ?$oid actual.raw &&
+					echo ?$oid >>expect.raw
+					;;
+				esac &&
+
+				sort actual.raw >actual &&
+				sort expect.raw >expect &&
+				test_cmp expect actual
+			'
+		done
+	done
+done
+
 test_done
diff --git a/t/t6030-bisect-porcelain.sh b/t/t6030-bisect-porcelain.sh
index 561080bf24..cdc0270640 100755
--- a/t/t6030-bisect-porcelain.sh
+++ b/t/t6030-bisect-porcelain.sh
@@ -878,7 +878,7 @@ test_expect_success 'broken branch creation' '
 
 echo "" > expected.ok
 cat > expected.missing-tree.default <<EOF
-fatal: unable to read tree $deleted
+fatal: unable to read tree ($deleted)
 EOF
 
 test_expect_success 'bisect fails if tree is broken on start commit' '
diff --git a/t/t6302-for-each-ref-filter.sh b/t/t6302-for-each-ref-filter.sh
index 82f3d1ea0f..948f1bb5f4 100755
--- a/t/t6302-for-each-ref-filter.sh
+++ b/t/t6302-for-each-ref-filter.sh
@@ -31,6 +31,37 @@ test_expect_success 'setup some history and refs' '
 	git update-ref refs/odd/spot main
 '
 
+test_expect_success '--include-root-refs pattern prints pseudorefs' '
+	cat >expect <<-\EOF &&
+	HEAD
+	ORIG_HEAD
+	refs/heads/main
+	refs/heads/side
+	refs/odd/spot
+	refs/tags/annotated-tag
+	refs/tags/doubly-annotated-tag
+	refs/tags/doubly-signed-tag
+	refs/tags/four
+	refs/tags/one
+	refs/tags/signed-tag
+	refs/tags/three
+	refs/tags/two
+	EOF
+	git update-ref ORIG_HEAD main &&
+	git for-each-ref --format="%(refname)" --include-root-refs >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success '--include-root-refs with other patterns' '
+	cat >expect <<-\EOF &&
+	HEAD
+	ORIG_HEAD
+	EOF
+	git update-ref ORIG_HEAD main &&
+	git for-each-ref --format="%(refname)" --include-root-refs "*HEAD" >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'filtering with --points-at' '
 	cat >expect <<-\EOF &&
 	refs/heads/main
diff --git a/t/t6437-submodule-merge.sh b/t/t6437-submodule-merge.sh
index 70650521b0..7a3f1cb27c 100755
--- a/t/t6437-submodule-merge.sh
+++ b/t/t6437-submodule-merge.sh
@@ -113,7 +113,7 @@ test_expect_success 'merging should conflict for non fast-forward' '
 	 git checkout -b test-nonforward-a b &&
 	  if test "$GIT_TEST_MERGE_ALGORITHM" = ort
 	  then
-		test_must_fail git merge c >actual &&
+		test_must_fail git merge c 2>actual &&
 		sub_expect="go to submodule (sub), and either merge commit $(git -C sub rev-parse --short sub-c)" &&
 		grep "$sub_expect" actual
 	  else
@@ -154,9 +154,9 @@ test_expect_success 'merging should conflict for non fast-forward (resolution ex
 	  git rev-parse --short sub-d > ../expect) &&
 	  if test "$GIT_TEST_MERGE_ALGORITHM" = ort
 	  then
-		test_must_fail git merge c >actual &&
+		test_must_fail git merge c >actual 2>sub-actual &&
 		sub_expect="go to submodule (sub), and either merge commit $(git -C sub rev-parse --short sub-c)" &&
-		grep "$sub_expect" actual
+		grep "$sub_expect" sub-actual
 	  else
 		test_must_fail git merge c 2> actual
 	  fi &&
@@ -181,9 +181,9 @@ test_expect_success 'merging should fail for ambiguous common parent' '
 	 ) &&
 	 if test "$GIT_TEST_MERGE_ALGORITHM" = ort
 	 then
-		test_must_fail git merge c >actual &&
+		test_must_fail git merge c >actual 2>sub-actual &&
 		sub_expect="go to submodule (sub), and either merge commit $(git -C sub rev-parse --short sub-c)" &&
-		grep "$sub_expect" actual
+		grep "$sub_expect" sub-actual
 	 else
 		test_must_fail git merge c 2> actual
 	 fi &&
@@ -227,7 +227,7 @@ test_expect_success 'merging should fail for changes that are backwards' '
 	git commit -a -m "f" &&
 
 	git checkout -b test-backward e &&
-	test_must_fail git merge f >actual &&
+	test_must_fail git merge f 2>actual &&
 	if test "$GIT_TEST_MERGE_ALGORITHM" = ort
     then
 		sub_expect="go to submodule (sub), and either merge commit $(git -C sub rev-parse --short sub-d)" &&
@@ -535,7 +535,7 @@ test_expect_success 'merging should fail with no merge base' '
 	git checkout -b b init &&
 	git add sub &&
 	git commit -m "b" &&
-	test_must_fail git merge a >actual &&
+	test_must_fail git merge a 2>actual &&
 	if test "$GIT_TEST_MERGE_ALGORITHM" = ort
     then
 		sub_expect="go to submodule (sub), and either merge commit $(git -C sub rev-parse --short HEAD^1)" &&
diff --git a/t/t7300-clean.sh b/t/t7300-clean.sh
index 611b3dd3ae..1f7201eb60 100755
--- a/t/t7300-clean.sh
+++ b/t/t7300-clean.sh
@@ -407,6 +407,12 @@ test_expect_success 'clean.requireForce and -f' '
 
 '
 
+test_expect_success 'clean.requireForce and --interactive' '
+	git clean --interactive </dev/null >output 2>error &&
+	test_grep ! "requireForce is true and" error &&
+	test_grep "\*\*\* Commands \*\*\*" output
+'
+
 test_expect_success 'core.excludesfile' '
 
 	echo excludes >excludes &&
diff --git a/t/t7402-submodule-rebase.sh b/t/t7402-submodule-rebase.sh
index 2b3c363078..aa2fdc31d1 100755
--- a/t/t7402-submodule-rebase.sh
+++ b/t/t7402-submodule-rebase.sh
@@ -116,7 +116,7 @@ test_expect_success 'rebasing submodule that should conflict' '
 	test_tick &&
 	git commit -m fourth &&
 
-	test_must_fail git rebase --onto HEAD^^ HEAD^ HEAD^0 >actual_output &&
+	test_must_fail git rebase --onto HEAD^^ HEAD^ HEAD^0 2>actual_output &&
 	git ls-files -s submodule >actual &&
 	(
 		cd submodule &&
diff --git a/t/t7502-commit-porcelain.sh b/t/t7502-commit-porcelain.sh
index a87c211d0b..b37e2018a7 100755
--- a/t/t7502-commit-porcelain.sh
+++ b/t/t7502-commit-porcelain.sh
@@ -736,6 +736,11 @@ test_expect_success 'message shows date when it is explicitly set' '
 	  .git/COMMIT_EDITMSG
 '
 
+test_expect_success 'message does not have multiple scissors lines' '
+	git commit --cleanup=scissors -v --allow-empty -e -m foo &&
+	test $(grep -c -e "--- >8 ---" .git/COMMIT_EDITMSG) -eq 1
+'
+
 test_expect_success AUTOIDENT 'message shows committer when it is automatic' '
 
 	echo >>negative &&
diff --git a/t/t7800-difftool.sh b/t/t7800-difftool.sh
index 6a36be1e63..96ae5d5880 100755
--- a/t/t7800-difftool.sh
+++ b/t/t7800-difftool.sh
@@ -91,58 +91,67 @@ test_expect_success 'difftool forwards arguments to diff' '
 	rm for-diff
 '
 
-test_expect_success 'difftool ignores exit code' '
-	test_config difftool.error.cmd false &&
-	git difftool -y -t error branch
-'
+for opt in '' '--dir-diff'
+do
+	test_expect_success "difftool ${opt} ignores exit code" "
+		test_config difftool.error.cmd false &&
+		git difftool ${opt} -y -t error branch
+	"
 
-test_expect_success 'difftool forwards exit code with --trust-exit-code' '
-	test_config difftool.error.cmd false &&
-	test_must_fail git difftool -y --trust-exit-code -t error branch
-'
+	test_expect_success "difftool ${opt} forwards exit code with --trust-exit-code" "
+		test_config difftool.error.cmd false &&
+		test_must_fail git difftool ${opt} -y --trust-exit-code -t error branch
+	"
 
-test_expect_success 'difftool forwards exit code with --trust-exit-code for built-ins' '
-	test_config difftool.vimdiff.path false &&
-	test_must_fail git difftool -y --trust-exit-code -t vimdiff branch
-'
+	test_expect_success "difftool ${opt} forwards exit code with --trust-exit-code for built-ins" "
+		test_config difftool.vimdiff.path false &&
+		test_must_fail git difftool ${opt} -y --trust-exit-code -t vimdiff branch
+	"
 
-test_expect_success 'difftool honors difftool.trustExitCode = true' '
-	test_config difftool.error.cmd false &&
-	test_config difftool.trustExitCode true &&
-	test_must_fail git difftool -y -t error branch
-'
+	test_expect_success "difftool ${opt} honors difftool.trustExitCode = true" "
+		test_config difftool.error.cmd false &&
+		test_config difftool.trustExitCode true &&
+		test_must_fail git difftool ${opt} -y -t error branch
+	"
 
-test_expect_success 'difftool honors difftool.trustExitCode = false' '
-	test_config difftool.error.cmd false &&
-	test_config difftool.trustExitCode false &&
-	git difftool -y -t error branch
-'
+	test_expect_success "difftool ${opt} honors difftool.trustExitCode = false" "
+		test_config difftool.error.cmd false &&
+		test_config difftool.trustExitCode false &&
+		git difftool ${opt} -y -t error branch
+	"
 
-test_expect_success 'difftool ignores exit code with --no-trust-exit-code' '
-	test_config difftool.error.cmd false &&
-	test_config difftool.trustExitCode true &&
-	git difftool -y --no-trust-exit-code -t error branch
-'
+	test_expect_success "difftool ${opt} ignores exit code with --no-trust-exit-code" "
+		test_config difftool.error.cmd false &&
+		test_config difftool.trustExitCode true &&
+		git difftool ${opt} -y --no-trust-exit-code -t error branch
+	"
 
-test_expect_success 'difftool stops on error with --trust-exit-code' '
-	test_when_finished "rm -f for-diff .git/fail-right-file" &&
-	test_when_finished "git reset -- for-diff" &&
-	write_script .git/fail-right-file <<-\EOF &&
-	echo failed
-	exit 1
-	EOF
-	>for-diff &&
-	git add for-diff &&
-	test_must_fail git difftool -y --trust-exit-code \
-		--extcmd .git/fail-right-file branch >actual &&
-	test_line_count = 1 actual
-'
+	test_expect_success "difftool ${opt} stops on error with --trust-exit-code" "
+		test_when_finished 'rm -f for-diff .git/fail-right-file' &&
+		test_when_finished 'git reset -- for-diff' &&
+		write_script .git/fail-right-file <<-\EOF &&
+		echo failed
+		exit 1
+		EOF
+		>for-diff &&
+		git add for-diff &&
+		test_must_fail git difftool ${opt} -y --trust-exit-code \
+			--extcmd .git/fail-right-file branch >actual &&
+		test_line_count = 1 actual
+	"
 
-test_expect_success 'difftool honors exit status if command not found' '
-	test_config difftool.nonexistent.cmd i-dont-exist &&
-	test_config difftool.trustExitCode false &&
-	test_must_fail git difftool -y -t nonexistent branch
-'
+	test_expect_success "difftool ${opt} honors exit status if command not found" "
+		test_config difftool.nonexistent.cmd i-dont-exist &&
+		test_config difftool.trustExitCode false &&
+		if test "${opt}" = '--dir-diff'
+		then
+			expected_code=127
+		else
+			expected_code=128
+		fi &&
+		test_expect_code \${expected_code} git difftool ${opt} -y -t nonexistent branch
+	"
+done
 
 test_expect_success 'difftool honors --gui' '
 	difftool_test_setup &&
diff --git a/t/t9117-git-svn-init-clone.sh b/t/t9117-git-svn-init-clone.sh
index 62de819a44..3b038c338f 100755
--- a/t/t9117-git-svn-init-clone.sh
+++ b/t/t9117-git-svn-init-clone.sh
@@ -17,32 +17,32 @@ test_expect_success 'setup svnrepo' '
 test_expect_success 'basic clone' '
 	test ! -d trunk &&
 	git svn clone "$svnrepo"/project/trunk &&
-	test -d trunk/.git/svn &&
-	test -e trunk/foo &&
+	test_path_is_dir trunk/.git/svn &&
+	test_path_exists trunk/foo &&
 	rm -rf trunk
 	'
 
 test_expect_success 'clone to target directory' '
 	test ! -d target &&
 	git svn clone "$svnrepo"/project/trunk target &&
-	test -d target/.git/svn &&
-	test -e target/foo &&
+	test_path_is_dir target/.git/svn &&
+	test_path_exists target/foo &&
 	rm -rf target
 	'
 
 test_expect_success 'clone with --stdlayout' '
 	test ! -d project &&
 	git svn clone -s "$svnrepo"/project &&
-	test -d project/.git/svn &&
-	test -e project/foo &&
+	test_path_is_dir project/.git/svn &&
+	test_path_exists project/foo &&
 	rm -rf project
 	'
 
 test_expect_success 'clone to target directory with --stdlayout' '
 	test ! -d target &&
 	git svn clone -s "$svnrepo"/project target &&
-	test -d target/.git/svn &&
-	test -e target/foo &&
+	test_path_is_dir target/.git/svn &&
+	test_path_exists target/foo &&
 	rm -rf target
 	'
 
diff --git a/t/t9146-git-svn-empty-dirs.sh b/t/t9146-git-svn-empty-dirs.sh
index 09606f1b3c..926ac81439 100755
--- a/t/t9146-git-svn-empty-dirs.sh
+++ b/t/t9146-git-svn-empty-dirs.sh
@@ -20,11 +20,7 @@ test_expect_success 'empty directories exist' '
 		cd cloned &&
 		for i in a b c d d/e d/e/f "weird file name"
 		do
-			if ! test -d "$i"
-			then
-				echo >&2 "$i does not exist" &&
-				exit 1
-			fi
+			test_path_is_dir "$i" || exit 1
 		done
 	)
 '
@@ -37,11 +33,7 @@ test_expect_success 'option automkdirs set to false' '
 		git svn fetch &&
 		for i in a b c d d/e d/e/f "weird file name"
 		do
-			if test -d "$i"
-			then
-				echo >&2 "$i exists" &&
-				exit 1
-			fi
+			test_path_is_missing "$i" || exit 1
 		done
 	)
 '
@@ -52,7 +44,7 @@ test_expect_success 'more emptiness' '
 
 test_expect_success 'git svn rebase creates empty directory' '
 	( cd cloned && git svn rebase ) &&
-	test -d cloned/"! !"
+	test_path_is_dir cloned/"! !"
 '
 
 test_expect_success 'git svn mkdirs recreates empty directories' '
@@ -62,11 +54,7 @@ test_expect_success 'git svn mkdirs recreates empty directories' '
 		git svn mkdirs &&
 		for i in a b c d d/e d/e/f "weird file name" "! !"
 		do
-			if ! test -d "$i"
-			then
-				echo >&2 "$i does not exist" &&
-				exit 1
-			fi
+			test_path_is_dir "$i" || exit 1
 		done
 	)
 '
@@ -78,25 +66,13 @@ test_expect_success 'git svn mkdirs -r works' '
 		git svn mkdirs -r7 &&
 		for i in a b c d d/e d/e/f "weird file name"
 		do
-			if ! test -d "$i"
-			then
-				echo >&2 "$i does not exist" &&
-				exit 1
-			fi
+			test_path_is_dir "$i" || exit 1
 		done &&
 
-		if test -d "! !"
-		then
-			echo >&2 "$i should not exist" &&
-			exit 1
-		fi &&
+		test_path_is_missing "! !" || exit 1 &&
 
 		git svn mkdirs -r8 &&
-		if ! test -d "! !"
-		then
-			echo >&2 "$i not exist" &&
-			exit 1
-		fi
+		test_path_is_dir "! !" || exit 1
 	)
 '
 
@@ -114,11 +90,7 @@ test_expect_success 'empty directories in trunk exist' '
 		cd trunk &&
 		for i in a "weird file name"
 		do
-			if ! test -d "$i"
-			then
-				echo >&2 "$i does not exist" &&
-				exit 1
-			fi
+			test_path_is_dir "$i" || exit 1
 		done
 	)
 '
@@ -129,7 +101,7 @@ test_expect_success 'remove a top-level directory from svn' '
 
 test_expect_success 'removed top-level directory does not exist' '
 	git svn clone "$svnrepo" removed &&
-	test ! -e removed/d
+	test_path_is_missing removed/d
 
 '
 unhandled=.git/svn/refs/remotes/git-svn/unhandled.log
@@ -143,15 +115,11 @@ test_expect_success 'git svn gc-ed files work' '
 			svn_cmd mkdir -m gz "$svnrepo"/gz &&
 			git reset --hard $(git rev-list HEAD | tail -1) &&
 			git svn rebase &&
-			test -f "$unhandled".gz &&
-			test -f "$unhandled" &&
+			test_path_is_file "$unhandled".gz &&
+			test_path_is_file "$unhandled" &&
 			for i in a b c "weird file name" gz "! !"
 			do
-				if ! test -d "$i"
-				then
-					echo >&2 "$i does not exist" &&
-					exit 1
-				fi
+				test_path_is_dir "$i" || exit 1
 			done
 		fi
 	)
diff --git a/t/unit-tests/t-ctype.c b/t/unit-tests/t-ctype.c
index f315489984..d6ac1fe678 100644
--- a/t/unit-tests/t-ctype.c
+++ b/t/unit-tests/t-ctype.c
@@ -1,30 +1,19 @@
 #include "test-lib.h"
 
-static int is_in(const char *s, int ch)
-{
-	/*
-	 * We can't find NUL using strchr. Accept it as the first
-	 * character in the spec -- there are no empty classes.
-	 */
-	if (ch == '\0')
-		return ch == *s;
-	if (*s == '\0')
-		s++;
-	return !!strchr(s, ch);
-}
-
-/* Macro to test a character type */
-#define TEST_CTYPE_FUNC(func, string) \
-static void test_ctype_##func(void) { \
-	for (int i = 0; i < 256; i++) { \
-		if (!check_int(func(i), ==, is_in(string, i))) \
-			test_msg("       i: 0x%02x", i); \
+#define TEST_CHAR_CLASS(class, string) do { \
+	size_t len = ARRAY_SIZE(string) - 1 + \
+		BUILD_ASSERT_OR_ZERO(ARRAY_SIZE(string) > 0) + \
+		BUILD_ASSERT_OR_ZERO(sizeof(string[0]) == sizeof(char)); \
+	int skip = test__run_begin(); \
+	if (!skip) { \
+		for (int i = 0; i < 256; i++) { \
+			if (!check_int(class(i), ==, !!memchr(string, i, len)))\
+				test_msg("      i: 0x%02x", i); \
+		} \
+		check(!class(EOF)); \
 	} \
-	if (!check(!func(EOF))) \
-			test_msg("      i: 0x%02x (EOF)", EOF); \
-}
-
-#define TEST_CHAR_CLASS(class) TEST(test_ctype_##class(), #class " works")
+	test__run_end(!skip, TEST_LOCATION(), #class " works"); \
+} while (0)
 
 #define DIGIT "0123456789"
 #define LOWER "abcdefghijklmnopqrstuvwxyz"
@@ -44,37 +33,21 @@ static void test_ctype_##func(void) { \
 	"\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f" \
 	"\x7f"
 
-TEST_CTYPE_FUNC(isdigit, DIGIT)
-TEST_CTYPE_FUNC(isspace, " \n\r\t")
-TEST_CTYPE_FUNC(isalpha, LOWER UPPER)
-TEST_CTYPE_FUNC(isalnum, LOWER UPPER DIGIT)
-TEST_CTYPE_FUNC(is_glob_special, "*?[\\")
-TEST_CTYPE_FUNC(is_regex_special, "$()*+.?[\\^{|")
-TEST_CTYPE_FUNC(is_pathspec_magic, "!\"#%&',-/:;<=>@_`~")
-TEST_CTYPE_FUNC(isascii, ASCII)
-TEST_CTYPE_FUNC(islower, LOWER)
-TEST_CTYPE_FUNC(isupper, UPPER)
-TEST_CTYPE_FUNC(iscntrl, CNTRL)
-TEST_CTYPE_FUNC(ispunct, PUNCT)
-TEST_CTYPE_FUNC(isxdigit, DIGIT "abcdefABCDEF")
-TEST_CTYPE_FUNC(isprint, LOWER UPPER DIGIT PUNCT " ")
-
 int cmd_main(int argc, const char **argv) {
-	/* Run all character type tests */
-	TEST_CHAR_CLASS(isspace);
-	TEST_CHAR_CLASS(isdigit);
-	TEST_CHAR_CLASS(isalpha);
-	TEST_CHAR_CLASS(isalnum);
-	TEST_CHAR_CLASS(is_glob_special);
-	TEST_CHAR_CLASS(is_regex_special);
-	TEST_CHAR_CLASS(is_pathspec_magic);
-	TEST_CHAR_CLASS(isascii);
-	TEST_CHAR_CLASS(islower);
-	TEST_CHAR_CLASS(isupper);
-	TEST_CHAR_CLASS(iscntrl);
-	TEST_CHAR_CLASS(ispunct);
-	TEST_CHAR_CLASS(isxdigit);
-	TEST_CHAR_CLASS(isprint);
+	TEST_CHAR_CLASS(isspace, " \n\r\t");
+	TEST_CHAR_CLASS(isdigit, DIGIT);
+	TEST_CHAR_CLASS(isalpha, LOWER UPPER);
+	TEST_CHAR_CLASS(isalnum, LOWER UPPER DIGIT);
+	TEST_CHAR_CLASS(is_glob_special, "*?[\\");
+	TEST_CHAR_CLASS(is_regex_special, "$()*+.?[\\^{|");
+	TEST_CHAR_CLASS(is_pathspec_magic, "!\"#%&',-/:;<=>@_`~");
+	TEST_CHAR_CLASS(isascii, ASCII);
+	TEST_CHAR_CLASS(islower, LOWER);
+	TEST_CHAR_CLASS(isupper, UPPER);
+	TEST_CHAR_CLASS(iscntrl, CNTRL);
+	TEST_CHAR_CLASS(ispunct, PUNCT);
+	TEST_CHAR_CLASS(isxdigit, DIGIT "abcdefABCDEF");
+	TEST_CHAR_CLASS(isprint, LOWER UPPER DIGIT PUNCT " ");
 
 	return test_done();
 }
diff --git a/tree-walk.c b/tree-walk.c
index b517792ba2..690fa6569b 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -100,7 +100,7 @@ void *fill_tree_descriptor(struct repository *r,
 	if (oid) {
 		buf = read_object_with_reference(r, oid, OBJ_TREE, &size, NULL);
 		if (!buf)
-			die("unable to read tree %s", oid_to_hex(oid));
+			die(_("unable to read tree (%s)"), oid_to_hex(oid));
 	}
 	init_tree_desc(desc, buf, size);
 	return buf;
diff --git a/upload-pack.c b/upload-pack.c
index 2537affa90..902144b9d3 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -28,6 +28,7 @@
 #include "shallow.h"
 #include "write-or-die.h"
 #include "json-writer.h"
+#include "strmap.h"
 
 /* Remember to update object flag allocation in object.h */
 #define THEY_HAVE	(1u << 11)
@@ -61,12 +62,11 @@ struct upload_pack_data {
 	struct string_list symref;				/* v0 only */
 	struct object_array want_obj;
 	struct object_array have_obj;
-	struct oid_array haves;					/* v2 only */
-	struct string_list wanted_refs;				/* v2 only */
+	struct strmap wanted_refs;				/* v2 only */
 	struct strvec hidden_refs;
 
 	struct object_array shallows;
-	struct string_list deepen_not;
+	struct oidset deepen_not;
 	struct object_array extra_edge_obj;
 	int depth;
 	timestamp_t deepen_since;
@@ -113,6 +113,8 @@ struct upload_pack_data {
 	unsigned done : 1;					/* v2 only */
 	unsigned allow_ref_in_want : 1;				/* v2 only */
 	unsigned allow_sideband_all : 1;			/* v2 only */
+	unsigned seen_haves : 1;				/* v2 only */
+	unsigned allow_packfile_uris : 1;			/* v2 only */
 	unsigned advertise_sid : 1;
 	unsigned sent_capabilities : 1;
 };
@@ -120,13 +122,12 @@ struct upload_pack_data {
 static void upload_pack_data_init(struct upload_pack_data *data)
 {
 	struct string_list symref = STRING_LIST_INIT_DUP;
-	struct string_list wanted_refs = STRING_LIST_INIT_DUP;
+	struct strmap wanted_refs = STRMAP_INIT;
 	struct strvec hidden_refs = STRVEC_INIT;
 	struct object_array want_obj = OBJECT_ARRAY_INIT;
 	struct object_array have_obj = OBJECT_ARRAY_INIT;
-	struct oid_array haves = OID_ARRAY_INIT;
 	struct object_array shallows = OBJECT_ARRAY_INIT;
-	struct string_list deepen_not = STRING_LIST_INIT_DUP;
+	struct oidset deepen_not = OID_ARRAY_INIT;
 	struct string_list uri_protocols = STRING_LIST_INIT_DUP;
 	struct object_array extra_edge_obj = OBJECT_ARRAY_INIT;
 	struct string_list allowed_filters = STRING_LIST_INIT_DUP;
@@ -137,7 +138,6 @@ static void upload_pack_data_init(struct upload_pack_data *data)
 	data->hidden_refs = hidden_refs;
 	data->want_obj = want_obj;
 	data->have_obj = have_obj;
-	data->haves = haves;
 	data->shallows = shallows;
 	data->deepen_not = deepen_not;
 	data->uri_protocols = uri_protocols;
@@ -155,13 +155,12 @@ static void upload_pack_data_init(struct upload_pack_data *data)
 static void upload_pack_data_clear(struct upload_pack_data *data)
 {
 	string_list_clear(&data->symref, 1);
-	string_list_clear(&data->wanted_refs, 1);
+	strmap_clear(&data->wanted_refs, 1);
 	strvec_clear(&data->hidden_refs);
 	object_array_clear(&data->want_obj);
 	object_array_clear(&data->have_obj);
-	oid_array_clear(&data->haves);
 	object_array_clear(&data->shallows);
-	string_list_clear(&data->deepen_not, 0);
+	oidset_clear(&data->deepen_not);
 	object_array_clear(&data->extra_edge_obj);
 	list_objects_filter_release(&data->filter_options);
 	string_list_clear(&data->allowed_filters, 0);
@@ -463,7 +462,7 @@ static void create_pack_file(struct upload_pack_data *pack_data,
 
  fail:
 	free(output_state);
-	send_client_data(3, abort_msg, sizeof(abort_msg),
+	send_client_data(3, abort_msg, strlen(abort_msg),
 			 pack_data->use_sideband);
 	die("git upload-pack: %s", abort_msg);
 }
@@ -471,7 +470,9 @@ static void create_pack_file(struct upload_pack_data *pack_data,
 static int do_got_oid(struct upload_pack_data *data, const struct object_id *oid)
 {
 	int we_knew_they_have = 0;
-	struct object *o = parse_object(the_repository, oid);
+	struct object *o = parse_object_with_flags(the_repository, oid,
+						   PARSE_OBJECT_SKIP_HASH_CHECK |
+						   PARSE_OBJECT_DISCARD_TREE);
 
 	if (!o)
 		die("oops (%s)", oid_to_hex(oid));
@@ -528,8 +529,6 @@ static int get_common_commits(struct upload_pack_data *data,
 	int got_other = 0;
 	int sent_ready = 0;
 
-	save_commit_buffer = 0;
-
 	for (;;) {
 		const char *arg;
 
@@ -926,12 +925,13 @@ static int send_shallow_list(struct upload_pack_data *data)
 		strvec_push(&av, "rev-list");
 		if (data->deepen_since)
 			strvec_pushf(&av, "--max-age=%"PRItime, data->deepen_since);
-		if (data->deepen_not.nr) {
+		if (oidset_size(&data->deepen_not)) {
+			const struct object_id *oid;
+			struct oidset_iter iter;
 			strvec_push(&av, "--not");
-			for (i = 0; i < data->deepen_not.nr; i++) {
-				struct string_list_item *s = data->deepen_not.items + i;
-				strvec_push(&av, s->string);
-			}
+			oidset_iter_init(&data->deepen_not, &iter);
+			while ((oid = oidset_iter_next(&iter)))
+				strvec_push(&av, oid_to_hex(oid));
 			strvec_push(&av, "--not");
 		}
 		for (i = 0; i < data->want_obj.nr; i++) {
@@ -1007,7 +1007,7 @@ static int process_deepen_since(const char *line, timestamp_t *deepen_since, int
 	return 0;
 }
 
-static int process_deepen_not(const char *line, struct string_list *deepen_not, int *deepen_rev_list)
+static int process_deepen_not(const char *line, struct oidset *deepen_not, int *deepen_rev_list)
 {
 	const char *arg;
 	if (skip_prefix(line, "deepen-not ", &arg)) {
@@ -1015,7 +1015,7 @@ static int process_deepen_not(const char *line, struct string_list *deepen_not,
 		struct object_id oid;
 		if (expand_ref(the_repository, arg, strlen(arg), &oid, &ref) != 1)
 			die("git upload-pack: ambiguous deepen-not: %s", line);
-		string_list_append(deepen_not, ref);
+		oidset_insert(deepen_not, &oid);
 		free(ref);
 		*deepen_rev_list = 1;
 		return 1;
@@ -1151,7 +1151,9 @@ static void receive_needs(struct upload_pack_data *data,
 			free(client_sid);
 		}
 
-		o = parse_object(the_repository, &oid_buf);
+		o = parse_object_with_flags(the_repository, &oid_buf,
+					    PARSE_OBJECT_SKIP_HASH_CHECK |
+					    PARSE_OBJECT_DISCARD_TREE);
 		if (!o) {
 			packet_writer_error(&data->writer,
 					    "upload-pack: not our ref %s",
@@ -1362,6 +1364,9 @@ static int upload_pack_config(const char *var, const char *value,
 		data->allow_ref_in_want = git_config_bool(var, value);
 	} else if (!strcmp("uploadpack.allowsidebandall", var)) {
 		data->allow_sideband_all = git_config_bool(var, value);
+	} else if (!strcmp("uploadpack.blobpackfileuri", var)) {
+		if (value)
+			data->allow_packfile_uris = 1;
 	} else if (!strcmp("core.precomposeunicode", var)) {
 		precomposed_unicode = git_config_bool(var, value);
 	} else if (!strcmp("transfer.advertisesid", var)) {
@@ -1385,10 +1390,13 @@ static int upload_pack_protected_config(const char *var, const char *value,
 	return 0;
 }
 
-static void get_upload_pack_config(struct upload_pack_data *data)
+static void get_upload_pack_config(struct repository *r,
+				   struct upload_pack_data *data)
 {
-	git_config(upload_pack_config, data);
+	repo_config(r, upload_pack_config, data);
 	git_protected_config(upload_pack_protected_config, data);
+
+	data->allow_sideband_all |= git_env_bool("GIT_TEST_SIDEBAND_ALL", 0);
 }
 
 void upload_pack(const int advertise_refs, const int stateless_rpc,
@@ -1398,7 +1406,7 @@ void upload_pack(const int advertise_refs, const int stateless_rpc,
 	struct upload_pack_data data;
 
 	upload_pack_data_init(&data);
-	get_upload_pack_config(&data);
+	get_upload_pack_config(the_repository, &data);
 
 	data.stateless_rpc = stateless_rpc;
 	data.timeout = timeout;
@@ -1468,7 +1476,8 @@ static int parse_want(struct packet_writer *writer, const char *line,
 			    "expected to get oid, not '%s'", line);
 
 		o = parse_object_with_flags(the_repository, &oid,
-					    PARSE_OBJECT_SKIP_HASH_CHECK);
+					    PARSE_OBJECT_SKIP_HASH_CHECK |
+					    PARSE_OBJECT_DISCARD_TREE);
 
 		if (!o) {
 			packet_writer_error(writer,
@@ -1490,14 +1499,13 @@ static int parse_want(struct packet_writer *writer, const char *line,
 }
 
 static int parse_want_ref(struct packet_writer *writer, const char *line,
-			  struct string_list *wanted_refs,
+			  struct strmap *wanted_refs,
 			  struct strvec *hidden_refs,
 			  struct object_array *want_obj)
 {
 	const char *refname_nons;
 	if (skip_prefix(line, "want-ref ", &refname_nons)) {
 		struct object_id oid;
-		struct string_list_item *item;
 		struct object *o = NULL;
 		struct strbuf refname = STRBUF_INIT;
 
@@ -1509,8 +1517,11 @@ static int parse_want_ref(struct packet_writer *writer, const char *line,
 		}
 		strbuf_release(&refname);
 
-		item = string_list_append(wanted_refs, refname_nons);
-		item->util = oiddup(&oid);
+		if (strmap_put(wanted_refs, refname_nons, oiddup(&oid))) {
+			packet_writer_error(writer, "duplicate want-ref %s",
+					    refname_nons);
+			die("duplicate want-ref %s", refname_nons);
+		}
 
 		if (!starts_with(refname_nons, "refs/tags/")) {
 			struct commit *commit = lookup_commit_in_graph(the_repository, &oid);
@@ -1532,15 +1543,14 @@ static int parse_want_ref(struct packet_writer *writer, const char *line,
 	return 0;
 }
 
-static int parse_have(const char *line, struct oid_array *haves)
+static int parse_have(const char *line, struct upload_pack_data *data)
 {
 	const char *arg;
 	if (skip_prefix(line, "have ", &arg)) {
 		struct object_id oid;
 
-		if (get_oid_hex(arg, &oid))
-			die("git upload-pack: expected SHA1 object, got '%s'", arg);
-		oid_array_append(haves, &oid);
+		got_oid(data, arg, &oid);
+		data->seen_haves = 1;
 		return 1;
 	}
 
@@ -1552,13 +1562,13 @@ static void trace2_fetch_info(struct upload_pack_data *data)
 	struct json_writer jw = JSON_WRITER_INIT;
 
 	jw_object_begin(&jw, 0);
-	jw_object_intmax(&jw, "haves", data->haves.nr);
+	jw_object_intmax(&jw, "haves", data->have_obj.nr);
 	jw_object_intmax(&jw, "wants", data->want_obj.nr);
-	jw_object_intmax(&jw, "want-refs", data->wanted_refs.nr);
+	jw_object_intmax(&jw, "want-refs", strmap_get_size(&data->wanted_refs));
 	jw_object_intmax(&jw, "depth", data->depth);
 	jw_object_intmax(&jw, "shallows", data->shallows.nr);
 	jw_object_bool(&jw, "deepen-since", data->deepen_since);
-	jw_object_intmax(&jw, "deepen-not", data->deepen_not.nr);
+	jw_object_intmax(&jw, "deepen-not", oidset_size(&data->deepen_not));
 	jw_object_bool(&jw, "deepen-relative", data->deepen_relative);
 	if (data->filter_options.choice)
 		jw_object_string(&jw, "filter", list_object_filter_config_name(data->filter_options.choice));
@@ -1586,7 +1596,7 @@ static void process_args(struct packet_reader *request,
 				   &data->hidden_refs, &data->want_obj))
 			continue;
 		/* process have line */
-		if (parse_have(arg, &data->haves))
+		if (parse_have(arg, data))
 			continue;
 
 		/* process args like thin-pack */
@@ -1638,14 +1648,17 @@ static void process_args(struct packet_reader *request,
 			continue;
 		}
 
-		if ((git_env_bool("GIT_TEST_SIDEBAND_ALL", 0) ||
-		     data->allow_sideband_all) &&
+		if (data->allow_sideband_all &&
 		    !strcmp(arg, "sideband-all")) {
 			data->writer.use_sideband = 1;
 			continue;
 		}
 
-		if (skip_prefix(arg, "packfile-uris ", &p)) {
+		if (data->allow_packfile_uris &&
+		    skip_prefix(arg, "packfile-uris ", &p)) {
+			if (data->uri_protocols.nr)
+				send_err_and_die(data,
+						 "multiple packfile-uris lines forbidden");
 			string_list_split(&data->uri_protocols, p, ',', -1);
 			continue;
 		}
@@ -1664,27 +1677,7 @@ static void process_args(struct packet_reader *request,
 		trace2_fetch_info(data);
 }
 
-static int process_haves(struct upload_pack_data *data, struct oid_array *common)
-{
-	int i;
-
-	/* Process haves */
-	for (i = 0; i < data->haves.nr; i++) {
-		const struct object_id *oid = &data->haves.oid[i];
-
-		if (!repo_has_object_file_with_flags(the_repository, oid,
-						     OBJECT_INFO_QUICK | OBJECT_INFO_SKIP_FETCH_OBJECT))
-			continue;
-
-		oid_array_append(common, oid);
-
-		do_got_oid(data, oid);
-	}
-
-	return 0;
-}
-
-static int send_acks(struct upload_pack_data *data, struct oid_array *acks)
+static int send_acks(struct upload_pack_data *data, struct object_array *acks)
 {
 	int i;
 
@@ -1696,7 +1689,7 @@ static int send_acks(struct upload_pack_data *data, struct oid_array *acks)
 
 	for (i = 0; i < acks->nr; i++) {
 		packet_writer_write(&data->writer, "ACK %s\n",
-				    oid_to_hex(&acks->oid[i]));
+				    oid_to_hex(&acks->objects[i].item->oid));
 	}
 
 	if (!data->wait_for_done && ok_to_give_up(data)) {
@@ -1710,13 +1703,11 @@ static int send_acks(struct upload_pack_data *data, struct oid_array *acks)
 
 static int process_haves_and_send_acks(struct upload_pack_data *data)
 {
-	struct oid_array common = OID_ARRAY_INIT;
 	int ret = 0;
 
-	process_haves(data, &common);
 	if (data->done) {
 		ret = 1;
-	} else if (send_acks(data, &common)) {
+	} else if (send_acks(data, &data->have_obj)) {
 		packet_writer_delim(&data->writer);
 		ret = 1;
 	} else {
@@ -1725,24 +1716,23 @@ static int process_haves_and_send_acks(struct upload_pack_data *data)
 		ret = 0;
 	}
 
-	oid_array_clear(&data->haves);
-	oid_array_clear(&common);
 	return ret;
 }
 
 static void send_wanted_ref_info(struct upload_pack_data *data)
 {
-	const struct string_list_item *item;
+	struct hashmap_iter iter;
+	const struct strmap_entry *e;
 
-	if (!data->wanted_refs.nr)
+	if (strmap_empty(&data->wanted_refs))
 		return;
 
 	packet_writer_write(&data->writer, "wanted-refs\n");
 
-	for_each_string_list_item(item, &data->wanted_refs) {
+	strmap_for_each_entry(&data->wanted_refs, &iter, e) {
 		packet_writer_write(&data->writer, "%s %s\n",
-				    oid_to_hex(item->util),
-				    item->string);
+				    oid_to_hex(e->value),
+				    e->key);
 	}
 
 	packet_writer_delim(&data->writer);
@@ -1771,7 +1761,7 @@ enum fetch_state {
 	FETCH_DONE,
 };
 
-int upload_pack_v2(struct repository *r UNUSED, struct packet_reader *request)
+int upload_pack_v2(struct repository *r, struct packet_reader *request)
 {
 	enum fetch_state state = FETCH_PROCESS_ARGS;
 	struct upload_pack_data data;
@@ -1780,7 +1770,7 @@ int upload_pack_v2(struct repository *r UNUSED, struct packet_reader *request)
 
 	upload_pack_data_init(&data);
 	data.use_sideband = LARGE_PACKET_MAX;
-	get_upload_pack_config(&data);
+	get_upload_pack_config(r, &data);
 
 	while (state != FETCH_DONE) {
 		switch (state) {
@@ -1796,7 +1786,7 @@ int upload_pack_v2(struct repository *r UNUSED, struct packet_reader *request)
 				 * they didn't want anything.
 				 */
 				state = FETCH_DONE;
-			} else if (data.haves.nr) {
+			} else if (data.seen_haves) {
 				/*
 				 * Request had 'have' lines, so lets ACK them.
 				 */
@@ -1839,41 +1829,28 @@ int upload_pack_v2(struct repository *r UNUSED, struct packet_reader *request)
 int upload_pack_advertise(struct repository *r,
 			  struct strbuf *value)
 {
-	if (value) {
-		int allow_filter_value;
-		int allow_ref_in_want;
-		int allow_sideband_all_value;
-		char *str = NULL;
+	struct upload_pack_data data;
 
+	upload_pack_data_init(&data);
+	get_upload_pack_config(r, &data);
+
+	if (value) {
 		strbuf_addstr(value, "shallow wait-for-done");
 
-		if (!repo_config_get_bool(r,
-					 "uploadpack.allowfilter",
-					 &allow_filter_value) &&
-		    allow_filter_value)
+		if (data.allow_filter)
 			strbuf_addstr(value, " filter");
 
-		if (!repo_config_get_bool(r,
-					 "uploadpack.allowrefinwant",
-					 &allow_ref_in_want) &&
-		    allow_ref_in_want)
+		if (data.allow_ref_in_want)
 			strbuf_addstr(value, " ref-in-want");
 
-		if (git_env_bool("GIT_TEST_SIDEBAND_ALL", 0) ||
-		    (!repo_config_get_bool(r,
-					   "uploadpack.allowsidebandall",
-					   &allow_sideband_all_value) &&
-		     allow_sideband_all_value))
+		if (data.allow_sideband_all)
 			strbuf_addstr(value, " sideband-all");
 
-		if (!repo_config_get_string(r,
-					    "uploadpack.blobpackfileuri",
-					    &str) &&
-		    str) {
+		if (data.allow_packfile_uris)
 			strbuf_addstr(value, " packfile-uris");
-			free(str);
-		}
 	}
 
+	upload_pack_data_clear(&data);
+
 	return 1;
 }
diff --git a/userdiff.c b/userdiff.c
index 2b1dab2649..92ef649c99 100644
--- a/userdiff.c
+++ b/userdiff.c
@@ -3,6 +3,7 @@
 #include "userdiff.h"
 #include "attr.h"
 #include "strbuf.h"
+#include "environment.h"
 
 static struct userdiff_driver *drivers;
 static int ndrivers;
@@ -459,7 +460,8 @@ struct userdiff_driver *userdiff_get_textconv(struct repository *r,
 	if (!driver->textconv)
 		return NULL;
 
-	if (driver->textconv_want_cache && !driver->textconv_cache) {
+	if (driver->textconv_want_cache && !driver->textconv_cache &&
+	    have_git_dir()) {
 		struct notes_cache *c = xmalloc(sizeof(*c));
 		struct strbuf name = STRBUF_INIT;
 
diff --git a/wt-status.c b/wt-status.c
index b5a29083df..7108a92b52 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -1107,12 +1107,15 @@ void wt_status_append_cut_line(struct strbuf *buf)
 	strbuf_add_commented_lines(buf, explanation, strlen(explanation), comment_line_char);
 }
 
-void wt_status_add_cut_line(FILE *fp)
+void wt_status_add_cut_line(struct wt_status *s)
 {
 	struct strbuf buf = STRBUF_INIT;
 
+	if (s->added_cut_line)
+		return;
+	s->added_cut_line = 1;
 	wt_status_append_cut_line(&buf);
-	fputs(buf.buf, fp);
+	fputs(buf.buf, s->fp);
 	strbuf_release(&buf);
 }
 
@@ -1143,11 +1146,12 @@ static void wt_longstatus_print_verbose(struct wt_status *s)
 	 * file (and even the "auto" setting won't work, since it
 	 * will have checked isatty on stdout). But we then do want
 	 * to insert the scissor line here to reliably remove the
-	 * diff before committing.
+	 * diff before committing, if we didn't already include one
+	 * before.
 	 */
 	if (s->fp != stdout) {
 		rev.diffopt.use_color = 0;
-		wt_status_add_cut_line(s->fp);
+		wt_status_add_cut_line(s);
 	}
 	if (s->verbose > 1 && s->committable) {
 		/* print_updated() printed a header, so do we */
diff --git a/wt-status.h b/wt-status.h
index 819dcad723..5e99ba4707 100644
--- a/wt-status.h
+++ b/wt-status.h
@@ -130,6 +130,7 @@ struct wt_status {
 	int rename_score;
 	int rename_limit;
 	enum wt_status_format status_format;
+	unsigned char added_cut_line; /* boolean */
 	struct wt_status_state state;
 	struct object_id oid_commit; /* when not Initial */
 
@@ -147,7 +148,7 @@ struct wt_status {
 
 size_t wt_status_locate_end(const char *s, size_t len);
 void wt_status_append_cut_line(struct strbuf *buf);
-void wt_status_add_cut_line(FILE *fp);
+void wt_status_add_cut_line(struct wt_status *s);
 void wt_status_prepare(struct repository *r, struct wt_status *s);
 void wt_status_print(struct wt_status *s);
 void wt_status_collect(struct wt_status *s);