DVCS where ancestry is not part of the revision-id?

[Stefan Monnier]

Does anyone know a DVCS where the revision-id is only computed from the
actual tree's content, without paying any attention to the ancestry and
the commit log?

This would seem to be a lot better than what we have now, since it would
make it easy to change commit logs after the fact, as well as change the
ancestry after the fact.

The main application would be for rebase: rebase would only change the
ancestry, by "explaining" the resulting tree as a new "cleaner" set of
patches, without screwing over people who were following the branch
before the rebase since the old ancestry is still there.

If course, it would make it possible to have cycles in the ancestry
(typically when you undo a change), so it would bring in all kinds of
new problems,


        Stefan