How to manage multiple svn repos via git
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README.md

README.md

Tips on how to manage multiple SVN paths via Git

Work in progress.

Setup local SVN repository for testing

Following code will setup a local SVN repository /tmp/test-svn and populate it with some real SVN data

mkdir /tmp/test-svn

# create empty repository
svnadmin create /tmp/test-svn

# install a pre-revprop-change hook script
echo -e "#"'!'"/bin/sh\nexit 0;" > /tmp/test-svn/hooks/pre-revprop-change
chmod +x /tmp/test-svn/hooks/pre-revprop-change

# sync our repos with a sample repository
svnsync init file:///tmp/test-svn http://progit-example.googlecode.com/svn/
svnsync sync file:///tmp/test-svn

http://git-scm.com/book/en/Git-and-Other-Systems-Git-and-Subversion

Init new local Git repository

mkdir localrepo
cd localrepo
git init
# Initialized empty Git repository in /tmp/localrepo/.git/

Add an existing SVN path to a local repository

Your settings are stored in .git/config

# Add a new svn-remote as remote branch named 'test-svn-trunk'
# Don't forget the trailing slash of the url
git config --add svn-remote.test-svn-trunk.url file:///tmp/test-svn/trunk/
git config --add svn-remote.test-svn-trunk.fetch :refs/remotes/test-svn-trunk

# Fetch the whole history in the new branch. Optional: -r BEGINNING_SVN_REVISION
git svn fetch test-svn-trunk

Branches

List local branches
# -a will list remotes, as well
git branch
Switch to branch
git checkout branch-name
Create new local branch to track a remote branch
git checkout -b local-test-svn-trunk -t test-svn-trunk
# Branch local-test-svn-trunk set up to track local ref refs/remotes/test-svn-trunk.
# Switched to a new branch 'local-test-svn-trunk'
Rename local branch
git branch -m old-branch new-branch
Rename remote branch
  • git gc to package all refs into .git/packed-refs

  • Edit .git/packed-refs, rename the branch

  • Edit .git/config, rename the branch

Changes in local branches

You make a new branch to store your work on some issue

git branch new-issue
git checkout new-issue

Then you do your work, commit/rebase/cherry-pick/whatever suits our needs and finally have a batch of commits ready for the upstream svn repo. Your local git repo history looks something like this:

A-B        <-- master
   \
    C-D-E  <-- new-issue

An easy thing git-svn can do for you is push merge commits as a squash of all the commits in the merged branch. This means that in the svn repo you can get a single commit that has all the changes you made in all your local commits in the new-issue branch

In order to do that and keep your local branches(so you have more information on what, when and how you did) you need to do the followiing:

# go back to your master branch, or whichever branch
# is tracking the svn upstream you want to push to
git checkout master

# rebase form the svn repository, so you're up to date
# before commiting back upstream
git svn rebase

# merge your local branch back into the branch
# that's tracking the svn repository
git merge new-issue

# push your changes upstream ot the svn repository
git svn dcommit

Most times merge commits in git are "empty", meaning that they have no diff assigned to them. They just have two parent commits, each from one of the branches that are being merged. In case of conflicts during merge, that git can not resolve on its own, the way you resolve the conflicts is added as a diff to the merge commit. For Subversion a commit is nothing more than a combination of diffs on files, so git's merge commits are meaningless in subversion context. So what you get with git-svn is that a merge commit is converted to a squash(see the man page) of the branch you've merged in and only after that commited upstream to the subversion repository.

If you look at your log now, you'll see your last commit is still a git merge commit, referencing the two branches you merged, but also has a subversion revision number assigned to it by git-svn.

!NB! If you do git svn rebase after you merge the branch back into master, the rebase could insert all the commits from svn back before you branched, depending on when you branched and when you last rebased from svn. So it's easier to just do the svn rebase before making the local merge commit.

Update external SVN path (svn up)

git svn rebase test-svn-trunk
# Current branch local-test-svn-trunk is up to date.

Apply selected commits from one branch to another

Git cherry-pick-ing is basically a shortcut for this SVN task:

  • export a patch file from a branch
  • move it to another branch
  • apply the patch
  • remove the temporary patch file

Initial branch structure

A-B              <-- master
   \
    C-D-E-F-G-H  <-- long_branch

Fork master branch into short_branch

git checkout master -b short_branch

Take commits E..H (left side is not inclusive) and apply them to short_branch

# Current active branch is `short_branch`
git cherry-pick E..H

The result:

    F'-G'-H'     <-- short_branch
   /
A-B              <-- master
   \
    C-D-E-F-G-H  <-- long_branch

http://stackoverflow.com/a/9853814
http://wiki.koha-community.org/wiki/Using_Git_Cherry_Pick

Backup your feature branches in an archive repository

git push ssh://user@your-backup-server/path/to/repo/ feature-branch-name

A successful Git branching model

http://nvie.com/posts/a-successful-git-branching-model/