git-svn: commit whole history of an existing git repository into an empty Subversion sub-directory

Question

I've been working on some code locally on my computer, tracking modifications using git (no remote). That code is now to become a module in a larger project, the code base of which is stored in Subversion (so something like https://svnserver/svnroot/project/trunk/module_x ), so I thought I could use git-svn to manage the Subversion repository as a remote. I remember doing that before for another project but could not find the modus operandi (changed computers in-between).

Here is what I tried:

cd ~/mygitrepo/
git svn init https://svnserver/svnroot/project/trunk/module_x
git svn fetch
git svn rebase

The last command yields the following error message:

Unable to determine upstream SVN information from working tree history

I read somewhere that it might be because the directory was empty in Subersion so I tried committing a dummy file to SVN separately then ran:

git svn fetch
    A   dummy.txt
r10744 = 89294ba713c6fed368f3b879c8dc7744b1015308 (refs/remotes/git-svn)

However, I cannot find the dummy.txt file in my git repo and both rebase and dcommit will continue to show the same error message. What did I do wrong?

Answer 1

Your checked out branch does not come from subversion, so git svn does not know how to work with it.

Git does, however, so what you need to do is use plain git rebase to rebase onto git-svn ( refs/remotes/git-svn ). Then the history will contain commits coming from subversion and git svn dcommit will know where to commit it.

Another thing is that your changes need to be placed in correct subdirectory before you try to rebase them, because git rebase does not support moving into subdirectory. git merge does, via the subdirectory strategy, but using merge will export to Subversion as a single commit. If you want to export full history, and you don't have it in correct directory in all commits , you will have to use git filter-branch to fix it up.

Answer 2

The answer provided by Jan gives the rationale for the error I encountered and points to plain old git rebase --onto as the proper solution but lacks the actual commands.

I initially proposed those commands as an edit to his answer but it was rejected, so here goes:

git checkout -b svnrebase git-svn            # create a temporary branch
git cherry-pick master~1                     # cherry pick the first  commit
git rebase --onto svnrebase master~1 master  # rebase the 2nd through current commit
git svn dcommit                              # finally commit the results to svn

NOTE that master~1 must be changed to reference your first commit to the git master. Here, we suppose we have a git repo with just two commits.

It is necessary to create a temporary branch and cherry-pick the first commit to master because rebase --onto only rebases the range of modifications made after master~1 (and the master~2 reference would not exist with just two commits).