Add revlog.parentrevs function.
This allows one to walk the revision graph using only revision numbers,
which can be faster than using revision hashes, especially for
RevlogNG, where the parents of a revision are stored as revision
numbers.
#!/bin/sh
hg init a
cd a
echo a > foo
hg rm foo
hg add foo
hg commit -m 1 -d "1000000 0"
hg remove
rm foo
hg remove foo
hg revert
rm foo
hg remove --after
hg commit -m 2 -d "1000000 0"
hg export 0
hg export 1
hg log -p -r 0
hg log -p -r 1
echo a > a
hg add a
hg rm a
hg rm -f a
echo b > b
hg ci -A -m 3 -d "1000001 0"
echo c >> b
hg rm b
hg rm -f b
cd ..
hg clone a b