Re: cvs import

[Michael Haggerty <mhagger@alum.mit.edu>]

Jon Smirl wrote:
> On 9/13/06, Markus Schiltknecht <markus@bluegap.ch> wrote:
>> Martin Langhoff wrote:
>> > On 9/14/06, Jon Smirl <jonsmirl@gmail.com> wrote:
>> >> Let's copy the git list too and maybe we can come up with one importer
>> >> for everyone.

That would be great.

> AFAIK none of the CVS converters are using the dependency algorithm.
> So the proposal on the table is to develop a new converter that uses
> the dependency data from CVS to form the change sets and then outputs
> this data in a form that all of the backends can consume. Of course
> each of the backends is going to have to write some code in order to
> consume this new import format.

Frankly, I think people are getting the priorities wrong by focusing on
the format of the output of cvs2svn.  Hacking a new output format onto
cvs2svn is a trivial matter of a couple hours of programming.

The real strength of cvs2svn (and I can say this without bragging
because most of this was done before I got involved in the project) is
that it handles dozens of peculiar corner cases and bizarre CVS
perversions, including a good test suite containing lots of twisted
little example repositories.  This is 90% of the intellectual content of
cvs2svn.

I've spent many, many hours refactoring and reengineering cvs2svn to
make it easy to modify and add new features.  The main thing that I want
to change is to use the dependency graph (rather than timestamps tweaked
to reflect dependency ordering) to deduce changesets.  But I would never
think of throwing away the "old" cvs2svn and starting anew, because then
I would have to add all the little corner cases again from scratch.

It would be nice to have a universal dumpfile format, but IMO not
critical.  The only difference between our SCMs that might be difficult
to paper over in a universal dumpfile is that SVN wants its changesets
in chronological order, whereas I gather that others would prefer the
data in dependency order branch by branch.

I say let cvs2svn (or if you like, we can rename it to "cvs2noncvs" :-)
) reconstruct the repository's change sets, then let us build several
backends that output the data in the format that is most convenient for
each project.

Michael