Introducing contrib/git-svn.

[thirdparty/git.git] / contrib / git-svn / 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 a single Subversion
branch and git.

git-svn is not to be confused with git-svnimport.  The were designed
with very different goals in mind.

git-svn is 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.  git-svnimport is designed
for read-only operation on repositories that match a particular layout
(albeit the recommended one by SVN developers).

For importing svn, git-svnimport is potentially more powerful when
operating on repositories organized under the recommended
trunk/branch/tags structure, and should be faster, too.

git-svn completely ignores the very limited view of branching that
Subversion has.  This allows git-svn to be much easier to use,
especially on repositories that are not organized in a manner that
git-svnimport is designed for.

COMMANDS
--------
init::
	Creates an empty git repository with additional metadata
	directories for git-svn.  The SVN_URL must be specified
	at this point.

fetch::
	Fetch unfetched revisions from the SVN_URL we are tracking.
	refs/heads/git-svn-HEAD will be updated to the latest revision.

commit::
	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.

rebuild::
	Not a part of daily usage, but this is a useful command if
	you've just cloned a repository (using git-clone) that was
	tracked with git-svn.  Unfortunately, git-clone does not clone
	git-svn metadata and the svn working tree that git-svn uses for
	its operations.  This rebuilds the metadata so git-svn can
	resume fetch operations.  SVN_URL may be optionally specified if
	the directory/repository you're tracking has moved or changed
	protocols.

OPTIONS
-------
-r <ARG>::
--revision <ARG>::
	Only used with the 'fetch' command.

	Takes any valid -r<argument> svn would accept and passes it
	directly to svn. -r<ARG1>:<ARG2> ranges and "{" DATE "}" syntax
	is also supported.  This is passed directly to svn, see svn
	documentation for more details.

	This can allow you to make partial mirrors when running fetch.

-::
--stdin::
	Only used with the 'commit' 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 'commit' command.

	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.

-e::
--edit::
	Only used with the 'commit' command.

	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.

COMPATIBILITY OPTIONS
---------------------
--no-ignore-externals::
	Only used with the 'fetch' and 'rebuild' command.

	By default, git-svn passes --ignore-externals to svn to avoid
	fetching svn:external trees into git.  Pass this flag to enable
	externals tracking directly via git.

	Versions of svn that do not support --ignore-externals are
	automatically detected and this flag will be automatically
	enabled for them.

	Otherwise, do not enable this flag unless you know what you're
	doing.

--no-stop-on-copy::
	Only used with the 'fetch' command.

	By default, git-svn passes --stop-on-copy to avoid dealing with
	the copied/renamed branch directory problem entirely.  A
	copied/renamed branch is the result of a <SVN_URL> being created
	in the past from a different source.  These are problematic to
	deal with even when working purely with svn if you work inside
	subdirectories.

	Do not use this flag unless you know exactly what you're getting
	yourself into.  You have been warned.

Examples
~~~~~~~~

Tracking and contributing to an Subversion managed-project:

# Initialize a tree (like git init-db)::
	git-svn init http://svn.foo.org/project/trunk
# Fetch remote revisions::
	git-svn fetch
# Create your own branch to hack on::
	git checkout -b my-branch git-svn-HEAD
# Commit only the git commits you want to SVN::
	git-svn commit <tree-ish> [<tree-ish_2> ...]
# Commit all the git commits from my-branch that don't exist in SVN::
	git rev-list --pretty=oneline git-svn-HEAD..my-branch | git-svn commit
# Something is committed to SVN, pull the latest into your branch::
	git-svn fetch && git pull . git-svn-HEAD

DESIGN PHILOSOPHY
-----------------
Merge tracking in Subversion is lacking and doing branched development
with Subversion is cumbersome as a result.  git-svn completely forgoes
any automated merge/branch tracking on the Subversion side and leaves it
entirely up to the user on the git side.  It's simply not worth it to do
a useful translation when the the original signal is weak.

TRACKING MULTIPLE REPOSITORIES OR BRANCHES
------------------------------------------
This is for advanced users, most users should ignore this section.

Because git-svn does not care about relationships between different
branches or directories in a Subversion repository, git-svn has a simple
hack to allow it to track an arbitrary number of related _or_ unrelated
SVN repositories via one git repository.  Simply set the GIT_SVN_ID
environment variable to a name other other than "git-svn" (the default)
and git-svn will ignore the contents of the $GIT_DIR/git-svn directory
and instead do all of its work in $GIT_DIR/$GIT_SVN_ID for that
invocation.

ADDITIONAL FETCH ARGUMENTS
--------------------------
This is for advanced users, most users should ignore this section.

Unfetched SVN revisions may be imported as children of existing commits
by specifying additional arguments to 'fetch'.  Additional parents may
optionally be specified in the form of sha1 hex sums at the
command-line.  Unfetched SVN revisions may also be tied to particular
git commits with the following syntax:

	svn_revision_number=git_commit_sha1

This allows you to tie unfetched SVN revision 375 to your current HEAD::

	git-svn fetch 375=$(git-rev-parse HEAD)

BUGS
----
If somebody commits a conflicting changeset to SVN at a bad moment
(right before you commit) causing a conflict and your commit to fail,
your svn working tree ($GIT_DIR/git-svn/tree) may be dirtied.  The
easiest thing to do is probably just to rm -rf $GIT_DIR/git-svn/tree and
run 'rebuild'.

We ignore all SVN properties except svn:executable.  Too difficult to
map them since we rely heavily on git write-tree being _exactly_ the
same on both the SVN and git working trees and I prefer not to clutter
working trees with metadata files.

svn:keywords can't be ignored in Subversion (at least I don't know of
a way to ignore them).

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

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