[Monotone-devel] cvs import

[Markus Schiltknecht]

Hi,

I've been trying to understand the cvsimport algorithm used by monotone 
and wanted to adjust that to be more like the one in cvs2svn.

I've had some problems with cvs2svn itself and began to question the 
algorithm used there. It turned out that the cvs2svn people have 
discussed an improved algorithms and are about to write a cvs2svn 2.0. 
The main problem with the current algorithm is that it depends on the 
timestamp information stored in the CVS repository.

Instead, it would be much better to just take the dependencies of the 
revisions into account. Considering the timestamp an irrelevant (for the 
import) attribute of the revision.

Now, that can be used to convert from CVS to about anything else. 
Obviously we were discussing about subversion, but then there was git, 
too. And monotone.

I'm beginning to question if one could come up with a generally useful 
cleaned-and-sane-CVS-changeset-dump-format, which could then be used by 
importers to all sort of VCSes. This would make monotone's cvsimport 
function dependent on cvs2svn (and therefore python). But the general 
try-to-get-something-usefull-from-an-insane-CVS-repository-algorithm 
would only have to be written once.

On the other hand, I see that lots of the cvsimport functionality for 
monotone has already been written (rcs file parsing, stuffing files, 
file deltas and complete revisions into the monotone database, etc..). 
Changing it to a better algorithm does not seem to be _that_ much work 
anymore. Plus the hard part seems to be to come up with a good 
algorithm, not implementing it. And we could still exchange our 
experience with the general algorithm with the cvs2svn people.

Plus, the guy who mentioned git pointed out that git needs quite a 
different dump-format than subversion to do an efficient conversion. I 
think coming up with a generally-usable dump format would not be that easy.

So you see, I'm slightly favoring the second implementation approach 
with a C++ implementation inside monotone.

Thoughts or comments?

Markus