revlog.py: always return tuples from parents and parentrevs There's at least one place doing parentrevs(rev) != (rev-1, -1), which is always true with revlog v0, since parentrevs returns a list in this case.

#!/bin/sh
hg init
echo This is file a1 > a
hg add a
hg commit -m "commit #0" -d "1000000 0"
ls
echo This is file b1 > b
hg add b
hg commit -m "commit #1" -d "1000000 0"
hg co 0
# B should disappear
ls