Git – Pushing an existing Git repository to SVN

gitgit-svnsvn

I've been doing all my work in Git and pushing to GitHub. I've been very happy with both the software and the site, and I have no wish to change my working practices at this point.

My PhD adviser is asking all students to keep their work in an SVN repository that's hosted at the university. I've found tons of documentation and tutorials about to pull down an existing SVN repository into Git, but nothing about pushing a Git repository to a fresh SVN repository. I expect there must be some way to do this with a combination of git-svn and a fresh branch and rebasing and all those wonderful terms, but I'm a Git newbie and don't feel confident with any of them.

I then want to just run a couple of commands to push commits to that SVN repository when I choose. I wish to keep using Git and just have the SVN repository mirror what's in Git.

I'll be the only person ever committing to SVN, if this makes any difference.

Best Answer

I needed this as well, and with the help of Bombe's answer + some fiddling around, I got it working. Here's the recipe:

Import Git -> Subversion

1. cd /path/to/git/localrepo
2. svn mkdir --parents protocol:///path/to/repo/PROJECT/trunk -m "Importing git repo"
3. git svn init protocol:///path/to/repo/PROJECT -s
4. git svn fetch
5. git rebase origin/trunk
5.1.  git status
5.2.  git add (conflicted-files)
5.3.  git rebase --continue
5.4.  (repeat 5.1.)
6. git svn dcommit

After #3 you'll get a cryptic message like this:

Using higher level of URL: protocol:///path/to/repo/PROJECT => protocol:///path/to/repo

Just ignore that.

When you run #5, you might get conflicts. Resolve these by adding files with state "unmerged" and resuming rebase. Eventually, you'll be done; then sync back to the SVN repository, using dcommit. That's all.

Keeping repositories in sync

You can now synchronise from SVN to Git, using the following commands:

git svn fetch
git rebase trunk

And to synchronise from Git to SVN, use:

git svn dcommit

Final note

You might want to try this out on a local copy, before applying to a live repository. You can make a copy of your Git repository to a temporary place; simply use cp -r, as all data is in the repository itself. You can then set up a file-based testing repository, using:

svnadmin create /home/name/tmp/test-repo

And check a working copy out, using:

svn co file:///home/name/tmp/test-repo svn-working-copy

That'll allow you to play around with things before making any lasting changes.

Addendum: If you mess up `git svn init`

If you accidentally run git svn init with the wrong URL, and you weren't smart enough to take a backup of your work (don't ask ...), you can't just run the same command again. You can however undo the changes by issuing:

rm -rf .git/svn
edit .git/config

And remove the section [svn-remote "svn"] section.

You can then run git svn init anew.

Related Solutions

Git – How to resolve merge conflicts in a Git repository

Try: git mergetool

It opens a GUI that steps you through each conflict, and you get to choose how to merge. Sometimes it requires a bit of hand editing afterwards, but usually it's enough by itself. It is much better than doing the whole thing by hand certainly.

As per Josh Glover's comment:

The command

doesn't necessarily open a GUI unless you install one. Running git mergetool for me resulted in vimdiff being used. You can install one of the following tools to use it instead: meld, opendiff, kdiff3, tkdiff, xxdiff, tortoisemerge, gvimdiff, diffuse, ecmerge, p4merge, araxis, vimdiff, emerge.

Below is the sample procedure to use vimdiff for resolve merge conflicts. Based on this link

Step 1: Run following commands in your terminal

git config merge.tool vimdiff
git config merge.conflictstyle diff3
git config mergetool.prompt false

This will set vimdiff as the default merge tool.

Step 2: Run following command in terminal

git mergetool

Step 3: You will see a vimdiff display in following format

  ╔═══════╦══════╦════════╗
  ║       ║      ║        ║
  ║ LOCAL ║ BASE ║ REMOTE ║
  ║       ║      ║        ║
  ╠═══════╩══════╩════════╣
  ║                       ║
  ║        MERGED         ║
  ║                       ║
  ╚═══════════════════════╝

These 4 views are

LOCAL – this is file from the current branch

BASE – common ancestor, how file looked before both changes

REMOTE – file you are merging into your branch

MERGED – merge result, this is what gets saved in the repo

You can navigate among these views using ctrl+w. You can directly reach MERGED view using ctrl+w followed by j.

More information about vimdiff navigation is here and here.

Step 4. You could edit the MERGED view the following way

If you want to get changes from REMOTE

:diffg RE

If you want to get changes from BASE

:diffg BA

If you want to get changes from LOCAL

:diffg LO

Step 5. Save, Exit, Commit and Clean up

:wqa save and exit from vi

git commit -m "message"

git clean Remove extra files (e.g. *.orig) created by diff tool.

Git – How to modify existing, unpushed commit messages

Amending the most recent commit message

git commit --amend

will open your editor, allowing you to change the commit message of the most recent commit. Additionally, you can set the commit message directly in the command line with:

git commit --amend -m "New commit message"

…however, this can make multi-line commit messages or small corrections more cumbersome to enter.

Make sure you don't have any working copy changes staged before doing this or they will get committed too. (Unstaged changes will not get committed.)

Changing the message of a commit that you've already pushed to your remote branch

If you've already pushed your commit up to your remote branch, then - after amending your commit locally (as described above) - you'll also need to force push the commit with:

git push <remote> <branch> --force
# Or
git push <remote> <branch> -f

Warning: force-pushing will overwrite the remote branch with the state of your local one. If there are commits on the remote branch that you don't have in your local branch, you will lose those commits.

Warning: be cautious about amending commits that you have already shared with other people. Amending commits essentially rewrites them to have different SHA IDs, which poses a problem if other people have copies of the old commit that you've rewritten. Anyone who has a copy of the old commit will need to synchronize their work with your newly re-written commit, which can sometimes be difficult, so make sure you coordinate with others when attempting to rewrite shared commit history, or just avoid rewriting shared commits altogether.

Perform an interactive rebase

Another option is to use interactive rebase. This allows you to edit any message you want to update even if it's not the latest message.

In order to do a Git squash, follow these steps:

// n is the number of commits up to the last commit you want to be able to edit
git rebase -i HEAD~n

Once you squash your commits - choose the e/r for editing the message:

Important note about interactive rebase

When you use git rebase -i HEAD~n there can be more than n commits. Git will "collect" all the commits in the last n commits, and if there was a merge somewhere in between that range you will see all the commits as well, so the outcome will be n + .

Good tip:

If you have to do it for more than a single branch and you might face conflicts when amending the content, set up git rerere and let Git resolve those conflicts automatically for you.