Felipe Contreras [off-list ref] writes:
[...]
Ok, thanks for pointing that out. I was thinking that maybe 'git
blame' would also be slightly faster on hg, but I really don't know.
hg (and git) store binary deltas. AFAIK neither attempts to use those
to produce output for blame, diff, etc. (git's deltas may well be
slightly different from mercurial's, in that git's can be deltas with
respect to something arbitrary so even if they had a suitable line-based
format they'd be useless for diff, blame.)
Similarly for the other major systems, with the exception of (I think)
bzr and darcs. (I don't know how bzr or darcs actually work, but IIRC
they both have line-based storage that in principle might be usable in
computing blame and diff.)
[...]