Re: git-svn and svn:externals, was Re: Hackontest ideas?

[Eric Wong <normalperson@yhbt.net>]

Johannes Schindelin <Johannes.Schindelin@gmx.de> wrote:
> Hi,
> 
> On Tue, 29 Jul 2008, Jakub Narebski wrote:
> 
> >  * handling of svn:externals using submodules
> 
> I doubt that this is easy.  Otherwise, Eric would have done it a long time 
> ago.

I started working on externals support a long time ago, but got hung up
on corner-cases (with .gitmodules and .gitignore being in the tree) and
backward-compatibility issues with commiting back to SVN.

The more I think about it, the more I think the worse-is-better approach
I used for "git svn show-ignore" is the way to go (using the unversioned
.git/info/exclude).  That would mean ignoring submodules as implemented
by git and just shotgunning another git-svn-created subdirectory into
where the external would've been...

> The main concern I have is to get the semantics right: AFAICT 
> svn:externals has _no notion_ of "what is current".  It just _always_ 
> fetches the HEAD.  Even if you check out an ancient revision in the 
> "superproject".

Based on my limited understanding, peg revisions are only needed in SVN
because of the cost of traversing history to DTRT.  git-svn should be
able to just use the -r<rev> syntax that has always been supported
without needing peg revisions.  On the other hand, implicit rename/copy
detection in git may not pick up drastic changes...

-- 
Eric Wong