Split off from bug 35574, which is fixed (adding basic support for it in ExtensionDistributor).

(In reply to bug 35574 comment #6)

Git support exists. Might need some work for extension branches in the future,
but considering we don't have a format for doing this yet, support can't be
added

So it is working for "master" right now. The support for using branches in the ExtensionDistributor is bug 37946.

This bug is for performing the actual creation of branches.

I don't think we need to find a "format". We can stick to using REL1_* branches for the ones we want to expose in ExtensionDistributor, and if an extension maintainer wants to create other branches, then that's perfectly fine.

The points to be resolved are these two:

• Doing the initial import. Since in SVN branches are copies, dealing with history is a bit complicated. Ideally we'd pick a point for each branch in each extensions's master that becomes that branch's HEAD (rather than importing the branch and thus basically duplicating history? Not sure if this is as bad/complicated as it seems). I've thought about maybe skipping this step, but I don't think that's realistic (yet). We don't want to keep mixing SVN and Git for te same extension (moreover since there are SVN-only and Git-only extensions / which are problematic right now). Users should be able to download old versions from Git.

• Keeping it up to date. Do we automatically branch all extensions when we branch core? I don't think that's a good idea. It shouldn't be a problem to make this a task for the extension maintainer(s). In Git it's also easy to create a branch afterwards from a certain revision. If an extension does not have any improvements over a release cycle, there is simply a gap in the number of branches available. Should be fine. Users can pick the newest version compatible with their version of MediaWiki.

Version: unspecified
Severity: normal