Re: [PATCH] Teach git-svn how to catch up with its tracking branches

[Junio C Hamano <gitster@pobox.com>]

Steven Grimm <koreth@midwinter.com> writes:

> In environments where a lot of people are sharing an svn repository using
> git-svn, everyone has identical, but individually maintained, tracking
> branches. If the svn repository is very active, it can take a while to
> run "git svn fetch" (which has to individually construct each revision
> by querying the svn server). It's much faster to run "git fetch" against
> another git-svn repository to grab the exact same git revisions you'd get
> from "git svn fetch". But until now, git-svn was confused by this because
> it didn't know how to incrementally rebuild its map of revision IDs.
> The only choice was to completely remove the map file and rebuild it
> from scratch, possibly a lengthy operation when there's a lot of history.
>
> With this change, git-svn will try to do an incremental update of its
> revision map if it sees that its tracking branch has svn revisions that
> aren't in the map yet.

Being able to have a shared git-svn managed git repository that mirrors
svn is something people have asked often enough, but the recommended
practice has always been for each to have his own copy.

Although I do not use git-svn heavily myself, I like this addition.  We
would probably want to update the in-tree doc to cover a recommended
pattern of interacting multiple git repositories with a single svn
repository on the other side?