[Monotone-devel] partial pull

[Bruce Stephens]

If the main way of verifying old revisions is netsync from new people,
then partial pull (meaning pulling only recent revisions) would seem
to be a problem.  You'd end up with only newer revisions being checked
regularly.

If that happens, my guess is it would be a really good idea to somehow
work out ways of surviving with corruption in older revisions---so
even if you can't reproduce a revision, it should be possible to do
everything with those revisions which *are* still reproducible.

For example, a few months ago I lost a revision in a subversion
repository (FSFS format, and one file got lost because of a sequence
of mishaps involving a power cut, an iffy Linux SATA driver, and
something else, IIRC).  Most revisions were still accessible (svn uses
skip deltas, I think, so just one or two couldn't be constructed), but
lots of other things simply failed: I couldn't see any way to recover
all the recoverable revisions ("svnadmin dump" just stopped at the
missing revision).

Eventually I just gave up---mostly it's a read-only version of our CVS
repository, so it's no big deal to recreate it (and by that time
Tailor had improved, so the result was better anyway).

An SCM ought to be able to do better than that, though.  svn really
ought to have been able to ignore the missing revisions (OK, perhaps
file renaming might have been lost, but even so...).