phases: avoid N² behavior in `advanceboundary`
We allowed duplicated entries in the deque, which each entry could potentially
insert all its ancestors. So advancing boundary for the full repository would
mean each revision would walk all its ancestors, resulting in O(N²) iteration.
For repository of any decent size, N² is quickly insane.
We introduce a simple set to avoid this and get back to reasonable performance.
#require no-pure
A script to generate nasty diff worst-case scenarios:
$ cat > s.py <<EOF
> import random
> for x in range(100000):
> print
> if random.randint(0, 100) >= 50:
> x += 1
> print(hex(x))
> EOF
$ hg init a
$ cd a
Check in a big file:
$ "$PYTHON" ../s.py > a
$ hg ci -qAm0
Modify it:
$ "$PYTHON" ../s.py > a
Time a check-in, should never take more than 10 seconds user time:
$ hg ci --time -m1 --config worker.enabled=no
time: real .* secs .user [0-9][.].* sys .* (re)