tests/heredoctest.py

match: support rooted globs in hgignore

In a .hgignore, "glob:foo" always means "**/foo". This cannot be
avoided because there is no syntax like "^" in regexes to say you
don't want the implied "**/" (of course one can use regexes, but glob
syntax is nice).

When you have a long list of fairly specific globs like
path/to/some/thing, this has two consequences:
1. unintended files may be ignored (not too common though)
2. matching performance can suffer significantly
  Here is vanilla hg status timing on a private repository:

  Using syntax:glob everywhere
  real	0m2.199s
  user	0m1.545s
  sys	0m0.619s

  When rooting the appropriate globs
  real	0m1.434s
  user	0m0.847s
  sys	0m0.565s

  (tangentially, none of this shows up in --profile's output. It
   seems that C code doesn't play well with profiling)

The code already supports this but there is no syntax to make use of
it, so it seems reasonable to create such syntax. I create a new
hgignore syntax "rootglob".

Differential Revision: https://phab.mercurial-scm.org/D5493

from __future__ import absolute_import, print_function

import sys

def flush():
    sys.stdout.flush()
    sys.stderr.flush()

globalvars = {}
lines = sys.stdin.readlines()
while lines:
    l = lines.pop(0)
    if l.startswith('SALT'):
        print(l[:-1])
    elif l.startswith('>>> '):
        snippet = l[4:]
        while lines and lines[0].startswith('... '):
            l = lines.pop(0)
            snippet += l[4:]
        c = compile(snippet, '<heredoc>', 'single')
        try:
            flush()
            exec(c, globalvars)
            flush()
        except Exception as inst:
            flush()
            print(repr(inst))