Re: Approaches to SVN to Git conversion (was: Re: [RFC] "Remote helper for Subversion" project)

[Stephen Bash <bash@genarts.com>]

----- Original Message -----
> From: "Nathan Gray" <n8gray@n8gray.org>
> Sent: Tuesday, March 6, 2012 2:29:59 PM
> Subject: Re: Approaches to SVN to Git conversion (was: Re: [RFC] "Remote helper for Subversion" project)
> 
> > > Personally, I think SVN export will always need a strong manual
> > > component to get the best results, so I've put quite a bit of work
> > > into designing a good SVN history format.  Like git-fast-import,
> > > it's an ASCII format designed both for human and machine
> > > consumption...
> >
> > First, I'm very impressed that you managed to get a language like
> > this up and working.  It could prove very useful going forward.   On
> > the flip side, from my experiments over the last year I've actually
> > been leaning toward a solution that is more implicit than explicit.
> > Taking git-svn as a model, I've been trying to define a mapping
> > system (in Perl):
> >
> >  my %branch_spec = { '/trunk/projname' => 'master',
> >                      '/branches/*/projname' => '/refs/heads/*' };
> >  my %tag_spec = { '/tags/*/projname' => '/refs/tags/*' };
> 
> The problem of specifying and detecting branches is a major problem in
> my upcoming conversion.  We've got toplevel trunk/branches/tags
> directories but underneath "branches" it's a free-for-all:
> 
> /branches/codenameA/{projectA,projectB,projectC}
> /branches/codenameB   (actually a branch of projectA)
> /branches/developers/joe/frobnicator-experiment (also a branch of
> projectA)
> 
> Clearly there's no simple regex that's going to capture this, so I'm
> reduced to listing every branch of projectA, which is tedious and
> error-prone.  However, what *would* work fabulously well for me is
> "marker file" detection.  Every copy of projectA has a certain file at
> it's root.  Let's call it "markerFile.txt".  What I'd really love is a
> way to say:
> 
> my %branch_markers = {'/branches/**/markerFile.txt' =>
>                       '/refs/heads/**'}

Ooo...  I like it.  I hadn't hit on this idea yet, but it certainly is a very helpful heuristic.  I doubt I'd have any sort of demo code for you in the near future, but it's definitely an idea to roll into the mix.

Thanks,
Stephen