Re: [GSoC] Git to SVN bridge

[Jonathan Nieder <jrnieder@gmail.com>]

Ramkumar Ramachandra wrote:

> Give 'vcs-svn/' the ability to spit out a Subversion dumpfile.  If you
> remember, we hit a brick wall last time when we needed a way to
> persist mark-referenced-blobs in the fast-import stream.

Yeah.  Ok, let's start there.

If I remember correctly, before we had this idea that svn-fi would be
a generic fast-import backend, so we could get support for pushing to
Subversion from other version control systems like Mercurial and RCS
for free.  An earlier idea was to use a very minimal subset of the
fast-import format.  You started with a patch that taught fast-export
a switch to produce that minimal subset, which was rejected because it
seemed like too much of a niche use case to be worth the cost to
compatibility.

However, that leaves whole swaths of the design space unexplored.  For
example, maybe "git fast-export" doesn't need to write the restricted
format but there would be a filter that takes an arbitrary fast-import
stream and converts it to the restricted thing.  Or maybe it would be
easiest to get something off the ground using that restricted
"fast-import lite" format and only afterwards expand svn-fi to handle
more commands so it can talk to the rest of the world.

In other words, if you are hitting a wall with that part which doesn't
seem to have much to do with differences between git and Subversion
anyway, I imagine there are easier places to start.  Alternatively, if
you prefer to work on making it easy for an importer to handle "ls"
and "cat" commands and mark references, I think our previous attempts
were misguided and we can do better. :)  What do you think?

Jonathan