shrink-revlog: add "reverse postorder" and "postorder reverse" toposorts.
Based on a patch by Benoit Boissinot, adapted to the pluggable sort
algorithm design. toposort_reversepostorder() is a very good
performer; it's designed to recreate what the revlog would have looked
like if Mercurial had parent deltas now. toposort_postorderreverse()
is unstable and very inconsistent, but perhaps with some work it could
be made better.
#!/bin/sh
hg init
echo a > a
hg ci -Am t
hg mv a b
hg ci -Am t1
hg debugrename b
hg mv b a
hg ci -Am t2
hg debugrename a
echo % test with --rev
hg debugrename --rev 1 b