patch: make parsepatch optionally trim context lines
Previously there is a suspicious `if False and delta > 0` which dates back
to the beginning of hgext/record.py (b2607267236d).
The "trimming context lines" feature could be useful (and is used by the
next patch). So let's enable it. This patch adds a new `maxcontext`
parameter to `recordhunk` and `parsepatch`, changing the `if False`
condition to respect it.
The old `trimcontext` implementation is also wrong - it does not update
`toline` correctly and it does not do the right thing for `before` context.
A doctest was added to guard us from making a similar mistake again.
Since `maxcontext` is set to `None` (unlimited), there is no behavior
change.
#require no-pure
A script to generate nasty diff worst-case scenarios:
$ cat > s.py <<EOF
> import random
> for x in xrange(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
time: real .* secs .user [0-9][.].* sys .* (re)