[darcs-users] Tips on a large merge, the big "initial import" takes forever

[David Roundy]

On Tue, Jan 29, 2008 at 12:15:42PM +0000, Matthew Bloch wrote:
> I'm trying to start a long-overdue merge of 9 months worth of changes -
> an external developer branched some old code into svn, worked on it
> quite a lot, and now he's finished I would like to merge it back to my
> darcs repo, i.e. in ascii art form:
> 
> + my darcs repo, April 2007
> |
> +----+ $dev1 copies repository, imports whole lot to svn
> |    |
> +    +
> |    | lots of check-ins on both svn & darcs branches
> +    + ...
> |    |
> +    +
> |    |
> ? <--/ svn rvn 106, Matt converts back to darcs with tailor
> |
> |
> 
> I've used tailor to convert his repo to darcs format, it looks
> convincing, the problem concerns that very first patch to the svn
> repository.
> 
> When I try to "darcs pull" that big import, darcs just chews on CPU for
> 24hrs (as long as I've left it) and I've no idea when or whether it is
> likely to finish.  I presume eventually it would decide there were no
> changes to make because our sources will be identical at the same date,
> but even if it's the right thing to do, I can't include a "CPU killer"
> patch which will freeze up for every single other merge that will need
> doing (probably 5 or 6).
>
> What I would like to do really is chuck away revision 1 from the
> converted svn repo, and "patch in" the darcs revision from which svn
> revision 1 was originally imported.  Then the pull wouldn't have to
> consider the giant patch at the start.

Yes, that's what you need to do.  I am sure tailor can do that, but don't
know how.  It sounds like what you're doing right now is trying to merge
two unrelated repositories that have 100% conflicting patches.  Darcs isn't
going to be able to do this.  If you construct two repositories with shared
history, then it should be no problem at all.  So it all comes down to
convincing tailor that that first commit isn't a change at all, and that
the initial state of the svn repository includes all the prior darcs
history.
-- 
David Roundy
Department of Physics
Oregon State University