Do any of the DVCS under consideration satisfy that requirement? I guess I'm asking whether you think all this talk about DVCSes is futile or premature?
I still do hope that Debian releases lenny before any of this advances. This would mean
bzr 1.5 git 1.5.6 mercurial 1.0.1
I don't have the experience with any of them to be able to tell whether they are good enough.
A year ago, the revision numbers were
bzr 1.0 git 1.5.4 mercurial 0.9.5
Again, I don't know these packages well enough to understand what these numbers mean. I know for bzr that apparently bzr 1.0 is considered unsuitable for anything, so this would be ruled out.
For git, 1.5.4 vs. 1.5.6 doesn't look too frightening, so the software appears to be in good shape. For Mercurial, the 1.0 release was made in March 2008, which might meet the "one year" criteria before this discussion is over.
I know that when switching to Subversion was discussed, there was opposition on grounds of subversion still being too young, and indeed, it took more than a year from the start of the discussion until the switch was made. I do think Subversion was mature since 1.0, which was released in Feb 2004; PEP 347 was written in August 2005; the switchover happened in Oct 2005.
So I think I will be fine if the software that I use has been mature for a year. From what I've heard, bazaar might not qualify (apparently, there were recent protocol changes); it seems that git would qualify. Whether mercurial is mature, and for how long it had been, I don't know.