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Should cvs2svn try to collect changesets at all?

From: Jason Molenda <jason-svn_at_molenda.com>
Date: 2001-04-17 18:48:48 CEST

I think this will be a tricky problem to solve. Is it worth solving
from the start? If the goal of collating individual checkins into
changesets is ignored, you get a subversion repository with lots
of one-file changes after the cvs2svn conversion, but it'll be a
lot easier to write cvs2svn. That doesn't seem so bad.

Ignoring all the resource issues, the first step is to generate a
list of 'changesets', or logically grouped check-ins, to the cvs
repo. You end up with a list like

2001-04-10T08:15:10 bob ChangeLog,1.832 foo.c,1.3 bar.h,1.18
2001-04-10T08:35:25 susan ChangeLog,1.833 baz.c,1.5 bar.h,1.19

etc.

The scenario I don't think is solvable -

 user bob starts his checkin at time T, across four directories,
 A, B, C, and D. He does each directory's checkin separately, but
 with the same commit message and close in time, so it is reasonable
 to expect that cvs2svn could collect all of these into a single
 atomic commit.

 At T+30sec, user susan checks in a file in directory C.

 At T+45sec, user bob gets to C, finds that his directory is not up to date,
 updates (and maybe resolves some conflicts) and does his commit.

I don't see how you can handle this scenario. Even detecting it
would be difficult. The changeset list would look like

2001-04-10T08:15:10 bob A/f,1.3 B/e,1.8 C/d,1.4 D/c,1.18
2001-04-10T08:35:25 susan C/d,1.3

cvs2svn has to notice that the T+30 checkin has an earlier revision
of a file than the T checkin, and break apart the T checkin into
two separate checkins, or maybe reschedule it to T+31.

In an attempt to collect individual cvs checkins into groupings,
we paper over the fact that cvs doesn't have atomic checkins, and
eventually cvs2svn will lose because of that.

J
Received on Sat Oct 21 14:36:28 2006

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