t4034: abstract away SHA-1-specific constants

[thirdparty/git.git] / Documentation / git-commit-graph.txt

git-commit-graph(1)
===================

NAME
----
git-commit-graph - Write and verify Git commit-graph files


SYNOPSIS
--------
[verse]
'git commit-graph read' [--object-dir <dir>]
'git commit-graph verify' [--object-dir <dir>] [--shallow]
'git commit-graph write' <options> [--object-dir <dir>]


DESCRIPTION
-----------

Manage the serialized commit-graph file.


OPTIONS
-------
--object-dir::
	Use given directory for the location of packfiles and commit-graph
	file. This parameter exists to specify the location of an alternate
	that only has the objects directory, not a full `.git` directory. The
	commit-graph file is expected to be in the `<dir>/info` directory and
	the packfiles are expected to be in `<dir>/pack`.


COMMANDS
--------
'write'::

Write a commit-graph file based on the commits found in packfiles.
+
With the `--stdin-packs` option, generate the new commit graph by
walking objects only in the specified pack-indexes. (Cannot be combined
with `--stdin-commits` or `--reachable`.)
+
With the `--stdin-commits` option, generate the new commit graph by
walking commits starting at the commits specified in stdin as a list
of OIDs in hex, one OID per line. (Cannot be combined with
`--stdin-packs` or `--reachable`.)
+
With the `--reachable` option, generate the new commit graph by walking
commits starting at all refs. (Cannot be combined with `--stdin-commits`
or `--stdin-packs`.)
+
With the `--append` option, include all commits that are present in the
existing commit-graph file.
+
With the `--split` option, write the commit-graph as a chain of multiple
commit-graph files stored in `<dir>/info/commit-graphs`. The new commits
not already in the commit-graph are added in a new "tip" file. This file
is merged with the existing file if the following merge conditions are
met:
+
* If `--size-multiple=<X>` is not specified, let `X` equal 2. If the new
tip file would have `N` commits and the previous tip has `M` commits and
`X` times `N` is greater than  `M`, instead merge the two files into a
single file.
+
* If `--max-commits=<M>` is specified with `M` a positive integer, and the
new tip file would have more than `M` commits, then instead merge the new
tip with the previous tip.
+
Finally, if `--expire-time=<datetime>` is not specified, let `datetime`
be the current time. After writing the split commit-graph, delete all
unused commit-graph whose modified times are older than `datetime`.

'read'::

Read the commit-graph file and output basic details about it.
Used for debugging purposes.

'verify'::

Read the commit-graph file and verify its contents against the object
database. Used to check for corrupted data.
+
With the `--shallow` option, only check the tip commit-graph file in
a chain of split commit-graphs.


EXAMPLES
--------

* Write a commit-graph file for the packed commits in your local `.git`
  directory.
+
------------------------------------------------
$ git commit-graph write
------------------------------------------------

* Write a commit-graph file, extending the current commit-graph file
  using commits in `<pack-index>`.
+
------------------------------------------------
$ echo <pack-index> | git commit-graph write --stdin-packs
------------------------------------------------

* Write a commit-graph file containing all reachable commits.
+
------------------------------------------------
$ git show-ref -s | git commit-graph write --stdin-commits
------------------------------------------------

* Write a commit-graph file containing all commits in the current
  commit-graph file along with those reachable from `HEAD`.
+
------------------------------------------------
$ git rev-parse HEAD | git commit-graph write --stdin-commits --append
------------------------------------------------

* Read basic information from the commit-graph file.
+
------------------------------------------------
$ git commit-graph read
------------------------------------------------


GIT
---
Part of the linkgit:git[1] suite