rewriteutil: check for divergence
This code is adapted from the code in the evolve extension. It seems
to be equivalent as far as the evolve extension's test suite can tell
(the only impact when making their `precheck()` delegate to our
version is that error messages are less detailed).
I had to change the error message to work with "change branch of"
being inserted as the action.
Differential Revision: https://phab.mercurial-scm.org/D10518
#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)