Re: Efficiency and correctness patches for git-svn mergeinfo support

[Sam Vilain <sam@vilain.net>]

On Sat, 2009-12-19 at 14:15 -0800, Andrew Myrick wrote:
> I tried cloning from a fairly recent revision that I knew was after
> our switchover to svn 1.5, and I received a number of these errors:
> 
>    Couldn't find revmap for [branch]
>    Exiting subroutine via next at /Users/adm/libexec/git-core/git-svn line 2983.
>    Exiting subroutine via next at /Users/adm/libexec/git-core/git-svn line 2983.
>    Exiting subroutine via next at /Users/adm/libexec/git-core/git-svn line 2983.
> 
> I'm not sure if this is expected, since I didn't clone from the whole
> repo, but it did cause a lot of spew.  I'm starting a fresh clone now,
> but it takes a few days to get through the whole repository.  I'm
> fairly new to git, so I would welcome any tips on how I can test this
> more quickly.

Whoops, no, not expected, I'll post a minor correction.  That means that
the branch which was merged in does not have git-svn metadata; ie, it's
not being tracked explicitly.  If people are doing merging of things
which aren't roots of branches you would expect this.  SVN, like
Perforce, supports a confusing amount of flexibility in its merge
tracking.  If [branch] is a real branch, then you'll want to see why it
doesn't have metadata yet.  Is it really a sub-tree of a real branch?
You could fetch it independently using a separate git-svn remote, or you
could ignore the warning; it should be relatively self-evident what
happened from the merge message and the contents of the changeset.

Note if your repository was significantly re-organized at any point, it
will pay to treat each section of history as a separate import project,
and stitch the results together afterwards using grafts and
filter-branch.

This version should be *significantly* faster than the old one.  ie, it
should not take a minute per commit while importing the heavily
merged-into integration branch.  Possibly a few seconds at most.

Sam