view tests/test-issue4074.t @ 38795:422d661056be

linelog: add a Python implementation of the linelog datastructure

This datastructure was originally developed by Jun Wu at Facebook,
inspired by SCCS weaves. It's useful as a cache for blame information,
but also is the magic that makes `hg absorb` easy to implement. In
service of importing the code to Mercurial, I wanted to actually
/understand/ it, and once I did I decided to take a run at
implementing it.

The help/internals/linelog.txt document is the README from Jun Wu's
implementaiton. It all applies to our linelog implementation.

Differential Revision: https://phab.mercurial-scm.org/D3990

#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)