patch: use a short, fixed-size message for last line of prompt (issue6158)
See issue6158 and the previous commit for examples of what might go wrong if we
have some combinations of readline version and terminal and need to wrap the
line.
Briefly: readline may not display the beginning of the last line of the prompt,
or it may print over it with the end of the prompt, making it difficult for
users to know what's going on.
Differential Revision: https://phab.mercurial-scm.org/D6563
#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)