threads / discuss / 11531

Importing merges when converting repos from SVN to Git (fusing grafts in the Git history)

Subject: Importing merges when converting repos from SVN to Git (fusing grafts in the Git history)

## tl;dr

3 messages between Jan 8, 2008 and Jan 21, 2008.

replies: 2people: 2as markdown or json

Benoit Sigoure· Jan 8, 2008, 14:48 UTC · lore

Hi list, I'm in the processing of converting the SVN repos of my company to Git. We have been using scripts to handle the merge hell with SVN and these scripts always mentioned what was merged where in the commit message. The first line is typically: merge -r FROM:TO https://svn.fake-company.com/svn/project/{trunk,branches/branch-name} I'm going to import the repositories with `git-svn' and then I'd like to rewrite the entire history to take these merges in account in the Git repo, if possible. This will probably help us merging the (former) SVN branches in our new Git repo. I know I can simulate a merge with a graft and I think it will be fairly easy to write a small script that parses the log and generates the corresponding graft file. Now the question is: how to make these grafts part of the *real* history so that we don't have to depend on the graft file anymore?

I know this issue has already been raised on the ML (the "how to include grafts are real merges in the history" thing) but I couldn't find the corresponding posts and can't remember the conclusion...

Thanks!

-- 
Benoit Sigoure aka Tsuna
EPITA Research and Development Laboratory

Johannes Sixt· Jan 8, 2008, 15:13 UTC · re: Benoit Sigoure · lore

Re: Importing merges when converting repos from SVN to Git (fusing grafts in the Git history)

Benoit Sigoure schrieb:

Show 12 quoted lines

> I'm going to import the repositories with `git-svn' and then I'd like to
> rewrite the entire history to take these merges in account in the Git
> repo, if possible.  This will probably help us merging the (former) SVN
> branches in our new Git repo.  I know I can simulate a merge with a
> graft and I think it will be fairly easy to write a small script that
> parses the log and generates the corresponding graft file.  Now the
> question is: how to make these grafts part of the *real* history so that
> we don't have to depend on the graft file anymore?
> 
> I know this issue has already been raised on the ML (the "how to include
> grafts are real merges in the history" thing) but I couldn't find the
> corresponding posts and can't remember the conclusion...

	git-filter-branch --tag-name-filter=cat --all

should do it. It rewrites nothing but the parenthood, so you will find that the rewritten history shares everything with the original history up to the first merge(s).

You better run this on a "cp -al" copy of the original converted repository because it *overwrites* the tags.

-- Hannes

Benoit Sigoure· Jan 21, 2008, 18:36 UTC · re: Johannes Sixt · lore

Re: Importing merges when converting repos from SVN to Git

Hi people, I wrote a script (svn-merge2git [1]) that helps to convert SVN merges to Git merges. The script basically detects the merges from their commit message and re-create them properly on the Git side. It took me several iterations to get it right but it eventually successfully converted a SVN repo with ~2500 revisions in a dozen of branches with ~100 merges in between them. The script can be used when one wants to entirely convert a SVN repo to a Git one while preserving the merges (that is, showing the merges in the Git history). I guess it can also be used to inject merges in the history of a git-svn repo to facilitate merging of SVN branches with Git, although I haven't had time to experiment this for now.

I hope this will be helpful to others.

[1] Code and explanations at: http://repo.or.cz/w/svn-merge2git.git

-- 
Benoit Sigoure aka Tsuna
EPITA Research and Development Laboratory