tests/test-status-inprocess.py

matcher: use re2 bindings if available

There are two sets of Python re2 bindings available on the internet;
this code works with both.

Using re2 can greatly improve "hg status" performance when a .hgignore
file becomes even modestly complex.

Example: "hg status" on a clean tree with 134K files, where "hg
debugignore" reports a regexp 4256 bytes in size.

  no .hgignore: 1.76 sec
  Python re:    2.79
  re2:          1.82

The overhead of regexp matching drops from 1.03 seconds with stock
re to 0.06 with re2.

(For comparison, a git repo with the same contents and .gitignore
file runs "git status -s" in 1.71 seconds, i.e. only slightly faster
than hg with re2.)

#!/usr/bin/python
from mercurial.ui import ui
from mercurial.localrepo import localrepository
from mercurial.commands import add, commit, status

u = ui()

print '% creating repo'
repo = localrepository(u, '.', create=True)

f = open('test.py', 'w')
try:
    f.write('foo\n')
finally:
    f.close

print '% add and commit'
add(u, repo, 'test.py')
commit(u, repo, message='*')
status(u, repo, clean=True)


print '% change'
f = open('test.py', 'w')
try:
    f.write('bar\n')
finally:
    f.close()

# this would return clean instead of changed before the fix
status(u, repo, clean=True, modified=True)