patch: move yielding "\n" to the end of loop
The original logic makes it harder to reason about - it yields the "\n"
character belonging to the last line in the next loop iteration.
The new code is in theory a little bit slower. But is more readable. It
makes the following changes easier to read.
Differential Revision: https://phab.mercurial-scm.org/D3210
#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
time: real .* secs .user [0-9][.].* sys .* (re)