git-svn: extract reusable code into utility functions

[thirdparty/git.git] / Documentation / git-svn.txt

git-svn(1)
==========

NAME
----
git-svn - Bidirectional operation between a single Subversion branch and git

SYNOPSIS
--------
'git-svn' <command> [options] [arguments]

DESCRIPTION
-----------
git-svn is a simple conduit for changesets between Subversion and git.
It is not to be confused with gitlink:git-svnimport[1], which is
read-only.

git-svn was originally designed for an individual developer who wants a
bidirectional flow of changesets between a single branch in Subversion
and an arbitrary number of branches in git.  Since its inception,
git-svn has gained the ability to track multiple branches in a manner
similar to git-svnimport.

git-svn is especially useful when it comes to tracking repositories
not organized in the way Subversion developers recommend (trunk,
branches, tags directories).

COMMANDS
--------
--

'init'::
	Initializes an empty git repository with additional
	metadata directories for git-svn.  The Subversion URL
	may be specified as a command-line argument, or as full
	URL arguments to -T/-t/-b.  Optionally, the target
	directory to operate on can be specified as a second
	argument.  Normally this command initializes the current
	directory.

-T<trunk_subdir>;;
--trunk=<trunk_subdir>;;
-t<tags_subdir>;;
--tags=<tags_subdir>;;
-b<branches_subdir>;;
--branches=<branches_subdir>;;
-s;;
--stdlayout;;
	These are optional command-line options for init.  Each of
	these flags can point to a relative repository path
	(--tags=project/tags') or a full url
	(--tags=https://foo.org/project/tags). The option --stdlayout is
	a shorthand way of setting trunk,tags,branches as the relative paths,
	which is the Subversion default. If any of the other options are given
	as well, they take precedence.
--no-metadata;;
	Set the 'noMetadata' option in the [svn-remote] config.
--use-svm-props;;
	Set the 'useSvmProps' option in the [svn-remote] config.
--use-svnsync-props;;
	Set the 'useSvnsyncProps' option in the [svn-remote] config.
--rewrite-root=<URL>;;
	Set the 'rewriteRoot' option in the [svn-remote] config.
--username=<USER>;;
	For transports that SVN handles authentication for (http,
	https, and plain svn), specify the username.  For other
	transports (eg svn+ssh://), you must include the username in
	the URL, eg svn+ssh://foo@svn.bar.com/project
--prefix=<prefix>;;
	This allows one to specify a prefix which is prepended
	to the names of remotes if trunk/branches/tags are
	specified.  The prefix does not automatically include a
	trailing slash, so be sure you include one in the
	argument if that is what you want.  If --branches/-b is
	specified, the prefix must include a trailing slash.
	Setting a prefix is useful if you wish to track multiple
	projects that share a common repository.

'fetch'::
	Fetch unfetched revisions from the Subversion remote we are
	tracking.  The name of the [svn-remote "..."] section in the
	.git/config file may be specified as an optional command-line
	argument.

'clone'::
	Runs 'init' and 'fetch'.  It will automatically create a
	directory based on the basename of the URL passed to it;
	or if a second argument is passed; it will create a directory
	and work within that.  It accepts all arguments that the
	'init' and 'fetch' commands accept; with the exception of
	'--fetch-all'.   After a repository is cloned, the 'fetch'
	command will be able to update revisions without affecting
	the working tree; and the 'rebase' command will be able
	to update the working tree with the latest changes.

'rebase'::
	This fetches revisions from the SVN parent of the current HEAD
	and rebases the current (uncommitted to SVN) work against it.

This works similarly to 'svn update' or 'git-pull' except that
it preserves linear history with 'git-rebase' instead of
'git-merge' for ease of dcommiting with git-svn.

This accepts all options that 'git-svn fetch' and 'git-rebase'
accepts.  However '--fetch-all' only fetches from the current
[svn-remote], and not all [svn-remote] definitions.

Like 'git-rebase'; this requires that the working tree be clean
and have no uncommitted changes.

-l;;
--local;;
	Do not fetch remotely; only run 'git-rebase' against the
	last fetched commit from the upstream SVN.

'dcommit'::
	Commit each diff from a specified head directly to the SVN
	repository, and then rebase or reset (depending on whether or
	not there is a diff between SVN and head).  This will create
	a revision in SVN for each commit in git.
	It is recommended that you run git-svn fetch and rebase (not
	pull or merge) your commits against the latest changes in the
	SVN repository.
	An optional command-line argument may be specified as an
	alternative to HEAD.
	This is advantageous over 'set-tree' (below) because it produces
	cleaner, more linear history.
+
--no-rebase;;
	After committing, do not rebase or reset.
--

'log'::
	This should make it easy to look up svn log messages when svn
	users refer to -r/--revision numbers.
+
The following features from `svn log' are supported:
+
--
--revision=<n>[:<n>];;
	is supported, non-numeric args are not:
	HEAD, NEXT, BASE, PREV, etc ...
-v/--verbose;;
	it's not completely compatible with the --verbose
	output in svn log, but reasonably close.
--limit=<n>;;
	is NOT the same as --max-count, doesn't count
	merged/excluded commits
--incremental;;
	supported
--
+
New features:
+
--
--show-commit;;
	shows the git commit sha1, as well
--oneline;;
	our version of --pretty=oneline
--
+
Any other arguments are passed directly to `git log'

--
'find-rev'::
	When given an SVN revision number of the form 'rN', returns the
	corresponding git commit hash (this can optionally be followed by a
	tree-ish to specify which branch should be searched).  When given a
	tree-ish, returns the corresponding SVN revision number.

'set-tree'::
	You should consider using 'dcommit' instead of this command.
	Commit specified commit or tree objects to SVN.  This relies on
	your imported fetch data being up-to-date.  This makes
	absolutely no attempts to do patching when committing to SVN, it
	simply overwrites files with those specified in the tree or
	commit.  All merging is assumed to have taken place
	independently of git-svn functions.

'show-ignore'::
	Recursively finds and lists the svn:ignore property on
	directories.  The output is suitable for appending to
	the $GIT_DIR/info/exclude file.

'commit-diff'::
	Commits the diff of two tree-ish arguments from the
	command-line.  This command is intended for interoperability with
	git-svnimport and does not rely on being inside an git-svn
	init-ed repository.  This command takes three arguments, (a) the
	original tree to diff against, (b) the new tree result, (c) the
	URL of the target Subversion repository.  The final argument
	(URL) may be omitted if you are working from a git-svn-aware
	repository (that has been init-ed with git-svn).
	The -r<revision> option is required for this.

--

OPTIONS
-------
--

--shared[={false|true|umask|group|all|world|everybody}]::
--template=<template_directory>::
	Only used with the 'init' command.
	These are passed directly to gitlink:git-init[1].

-r <ARG>::
--revision <ARG>::

Used with the 'fetch' command.

This allows revision ranges for partial/cauterized history
to be supported.  $NUMBER, $NUMBER1:$NUMBER2 (numeric ranges),
$NUMBER:HEAD, and BASE:$NUMBER are all supported.

This can allow you to make partial mirrors when running fetch;
but is generally not recommended because history will be skipped
and lost.

-::
--stdin::

Only used with the 'set-tree' command.

Read a list of commits from stdin and commit them in reverse
order.  Only the leading sha1 is read from each line, so
git-rev-list --pretty=oneline output can be used.

--rmdir::

Only used with the 'dcommit', 'set-tree' and 'commit-diff' commands.

Remove directories from the SVN tree if there are no files left
behind.  SVN can version empty directories, and they are not
removed by default if there are no files left in them.  git
cannot version empty directories.  Enabling this flag will make
the commit to SVN act like git.

config key: svn.rmdir

-e::
--edit::

Only used with the 'dcommit', 'set-tree' and 'commit-diff' commands.

Edit the commit message before committing to SVN.  This is off by
default for objects that are commits, and forced on when committing
tree objects.

config key: svn.edit

-l<num>::
--find-copies-harder::

Only used with the 'dcommit', 'set-tree' and 'commit-diff' commands.

They are both passed directly to git-diff-tree see
gitlink:git-diff-tree[1] for more information.

[verse]
config key: svn.l
config key: svn.findcopiesharder

-A<filename>::
--authors-file=<filename>::

Syntax is compatible with the files used by git-svnimport and
git-cvsimport:

------------------------------------------------------------------------
	loginname = Joe User <user@example.com>
------------------------------------------------------------------------

If this option is specified and git-svn encounters an SVN
committer name that does not exist in the authors-file, git-svn
will abort operation. The user will then have to add the
appropriate entry.  Re-running the previous git-svn command
after the authors-file is modified should continue operation.

config key: svn.authorsfile

-q::
--quiet::
	Make git-svn less verbose.

--repack[=<n>]::
--repack-flags=<flags>::

These should help keep disk usage sane for large fetches
with many revisions.

--repack takes an optional argument for the number of revisions
to fetch before repacking.  This defaults to repacking every
1000 commits fetched if no argument is specified.

--repack-flags are passed directly to gitlink:git-repack[1].

[verse]
config key: svn.repack
config key: svn.repackflags

-m::
--merge::
-s<strategy>::
--strategy=<strategy>::

These are only used with the 'dcommit' and 'rebase' commands.

Passed directly to git-rebase when using 'dcommit' if a
'git-reset' cannot be used (see dcommit).

-n::
--dry-run::

This is only used with the 'dcommit' command.

Print out the series of git arguments that would show
which diffs would be committed to SVN.

--

ADVANCED OPTIONS
----------------
--

-i<GIT_SVN_ID>::
--id <GIT_SVN_ID>::

This sets GIT_SVN_ID (instead of using the environment).  This
allows the user to override the default refname to fetch from
when tracking a single URL.  The 'log' and 'dcommit' commands
no longer require this switch as an argument.

-R<remote name>::
--svn-remote <remote name>::
	Specify the [svn-remote "<remote name>"] section to use,
	this allows SVN multiple repositories to be tracked.
	Default: "svn"

--follow-parent::
	This is especially helpful when we're tracking a directory
	that has been moved around within the repository, or if we
	started tracking a branch and never tracked the trunk it was
	descended from. This feature is enabled by default, use
	--no-follow-parent to disable it.

config key: svn.followparent

--
CONFIG FILE-ONLY OPTIONS
------------------------
--

svn.noMetadata::
svn-remote.<name>.noMetadata::

This gets rid of the git-svn-id: lines at the end of every commit.

If you lose your .git/svn/git-svn/.rev_db file, git-svn will not
be able to rebuild it and you won't be able to fetch again,
either.  This is fine for one-shot imports.

The 'git-svn log' command will not work on repositories using
this, either.  Using this conflicts with the 'useSvmProps'
option for (hopefully) obvious reasons.

svn.useSvmProps::
svn-remote.<name>.useSvmProps::

This allows git-svn to re-map repository URLs and UUIDs from
mirrors created using SVN::Mirror (or svk) for metadata.

If an SVN revision has a property, "svm:headrev", it is likely
that the revision was created by SVN::Mirror (also used by SVK).
The property contains a repository UUID and a revision.  We want
to make it look like we are mirroring the original URL, so
introduce a helper function that returns the original identity
URL and UUID, and use it when generating metadata in commit
messages.

svn.useSvnsyncProps::
svn-remote.<name>.useSvnsyncprops::
	Similar to the useSvmProps option; this is for users
	of the svnsync(1) command distributed with SVN 1.4.x and
	later.

svn-remote.<name>.rewriteRoot::
	This allows users to create repositories from alternate
	URLs.  For example, an administrator could run git-svn on the
	server locally (accessing via file://) but wish to distribute
	the repository with a public http:// or svn:// URL in the
	metadata so users of it will see the public URL.

Since the noMetadata, rewriteRoot, useSvnsyncProps and useSvmProps
options all affect the metadata generated and used by git-svn; they
*must* be set in the configuration file before any history is imported
and these settings should never be changed once they are set.

Additionally, only one of these four options can be used per-svn-remote
section because they affect the 'git-svn-id:' metadata line.

--

BASIC EXAMPLES
--------------

Tracking and contributing to the trunk of a Subversion-managed project:

------------------------------------------------------------------------
# Clone a repo (like git clone):
	git-svn clone http://svn.foo.org/project/trunk
# Enter the newly cloned directory:
	cd trunk
# You should be on master branch, double-check with git-branch
	git branch
# Do some work and commit locally to git:
	git commit ...
# Something is committed to SVN, rebase your local changes against the
# latest changes in SVN:
	git-svn rebase
# Now commit your changes (that were committed previously using git) to SVN,
# as well as automatically updating your working HEAD:
	git-svn dcommit
# Append svn:ignore settings to the default git exclude file:
	git-svn show-ignore >> .git/info/exclude
------------------------------------------------------------------------

Tracking and contributing to an entire Subversion-managed project
(complete with a trunk, tags and branches):

------------------------------------------------------------------------
# Clone a repo (like git clone):
	git-svn clone http://svn.foo.org/project -T trunk -b branches -t tags
# View all branches and tags you have cloned:
	git branch -r
# Reset your master to trunk (or any other branch, replacing 'trunk'
# with the appropriate name):
	git reset --hard remotes/trunk
# You may only dcommit to one branch/tag/trunk at a time.  The usage
# of dcommit/rebase/show-ignore should be the same as above.
------------------------------------------------------------------------

The initial 'git-svn clone' can be quite time-consuming
(especially for large Subversion repositories). If multiple
people (or one person with multiple machines) want to use
git-svn to interact with the same Subversion repository, you can
do the initial 'git-svn clone' to a repository on a server and
have each person clone that repository with 'git clone':

------------------------------------------------------------------------
# Do the initial import on a server
	ssh server "cd /pub && git-svn clone http://svn.foo.org/project
# Clone locally
	git clone server:/pub/project
# Tell git-svn which branch contains the Subversion commits
	git update-ref refs/remotes/git-svn origin/master
# Initialize git-svn locally (be sure to use the same URL and -T/-b/-t options as were used on server)
	git-svn init http://svn.foo.org/project
# Pull the latest changes from Subversion
	git-svn rebase
------------------------------------------------------------------------

REBASE VS. PULL/MERGE
---------------------

Originally, git-svn recommended that the remotes/git-svn branch be
pulled or merged from.  This is because the author favored
'git-svn set-tree B' to commit a single head rather than the
'git-svn set-tree A..B' notation to commit multiple commits.

If you use 'git-svn set-tree A..B' to commit several diffs and you do
not have the latest remotes/git-svn merged into my-branch, you should
use 'git-svn rebase' to update your work branch instead of 'git pull' or
'git merge'.  'pull/merge' can cause non-linear history to be flattened
when committing into SVN, which can lead to merge commits reversing
previous commits in SVN.

DESIGN PHILOSOPHY
-----------------
Merge tracking in Subversion is lacking and doing branched development
with Subversion can be cumbersome as a result.  While git-svn can track
copy history (including branches and tags) for repositories adopting a
standard layout, it cannot yet represent merge history that happened
inside git back upstream to SVN users.  Therefore it is advised that
users keep history as linear as possible inside git to ease
compatibility with SVN (see the CAVEATS section below).

CAVEATS
-------

For the sake of simplicity and interoperating with a less-capable system
(SVN), it is recommended that all git-svn users clone, fetch and dcommit
directly from the SVN server, and avoid all git-clone/pull/merge/push
operations between git repositories and branches.  The recommended
method of exchanging code between git branches and users is
git-format-patch and git-am, or just dcommiting to the SVN repository.

Running 'git-merge' or 'git-pull' is NOT recommended on a branch you
plan to dcommit from.  Subversion does not represent merges in any
reasonable or useful fashion; so users using Subversion cannot see any
merges you've made.  Furthermore, if you merge or pull from a git branch
that is a mirror of an SVN branch, dcommit may commit to the wrong
branch.

'git-clone' does not clone branches under the refs/remotes/ hierarchy or
any git-svn metadata, or config.  So repositories created and managed with
using git-svn should use rsync(1) for cloning, if cloning is to be done
at all.

Since 'dcommit' uses rebase internally, any git branches you git-push to
before dcommit on will require forcing an overwrite of the existing ref
on the remote repository.  This is generally considered bad practice,
see the git-push(1) documentation for details.

Do not use the --amend option of git-commit(1) on a change you've
already dcommitted.  It is considered bad practice to --amend commits
you've already pushed to a remote repository for other users, and
dcommit with SVN is analogous to that.

BUGS
----

We ignore all SVN properties except svn:executable.  Any unhandled
properties are logged to $GIT_DIR/svn/<refname>/unhandled.log

Renamed and copied directories are not detected by git and hence not
tracked when committing to SVN.  I do not plan on adding support for
this as it's quite difficult and time-consuming to get working for all
the possible corner cases (git doesn't do it, either).  Committing
renamed and copied files are fully supported if they're similar enough
for git to detect them.

CONFIGURATION
-------------

git-svn stores [svn-remote] configuration information in the
repository .git/config file.  It is similar the core git
[remote] sections except 'fetch' keys do not accept glob
arguments; but they are instead handled by the 'branches'
and 'tags' keys.  Since some SVN repositories are oddly
configured with multiple projects glob expansions such those
listed below are allowed:

------------------------------------------------------------------------
[svn-remote "project-a"]
	url = http://server.org/svn
	branches = branches/*/project-a:refs/remotes/project-a/branches/*
	tags = tags/*/project-a:refs/remotes/project-a/tags/*
	trunk = trunk/project-a:refs/remotes/project-a/trunk
------------------------------------------------------------------------

Keep in mind that the '*' (asterisk) wildcard of the local ref
(right of the ':') *must* be the farthest right path component;
however the remote wildcard may be anywhere as long as it's own
independent path component (surrounded by '/' or EOL).   This
type of configuration is not automatically created by 'init' and
should be manually entered with a text-editor or using
gitlink:git-config[1]

SEE ALSO
--------
gitlink:git-rebase[1]

Author
------
Written by Eric Wong <normalperson@yhbt.net>.

Documentation
-------------
Written by Eric Wong <normalperson@yhbt.net>.