contrib/check-config.py

transaction: avoid file stat ambiguity only for files in blacklist

Advancing mtime by os.utime() fails for EPERM, if the target file is
owned by another. bff5ccbe5ead and related changes made some code
paths give advancing mtime up in such case, to fix issue5418.

This causes file stat ambiguity (again), if it is owned by another.

    https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan

To avoid file stat ambiguity in such case, especially for
.hg/dirstate, ed66ec39933f made vfs.rename() copy the target file, and
advance mtime of renamed one again, if EPERM (see issue5584 for detail).

But straightforward "copy if EPERM" isn't reasonable for truncation of
append-only files at rollbacking, because rollbacking might cost much
for truncation of many filelogs, even though filelogs aren't
filecache-ed.

Therefore, this patch introduces blacklist "checkambigfiles", and
avoids file stat ambiguity only for files specified in this blacklist.

This patch consists of two parts below, which should be applied at
once in order to avoid regression.

  - specify 'checkambig=True' at vfs.open(mode='a') in _playback()
    according to checkambigfiles

  - invoke _playback() with checkambigfiles
    - add transaction.__init__() checkambigfiles argument, for _abort()
      - make localrepo instantiate transaction with _cachedfiles
    - add rollback() checkambigfiles argument, for "hg rollback/recover"
      - make localrepo invoke rollback() with _cachedfiles

After this patch, straightforward "copy if EPERM" will be reasonable
at closing the file opened with checkambig=True, because this policy
is applied only on files, which are listed in blacklist
"checkambigfiles".

#!/usr/bin/env python
#
# check-config - a config flag documentation checker for Mercurial
#
# Copyright 2015 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import, print_function
import re
import sys

foundopts = {}
documented = {}
allowinconsistent = set()

configre = re.compile(r'''
    # Function call
    ui\.config(?P<ctype>|int|bool|list)\(
        # First argument.
        ['"](?P<section>\S+)['"],\s*
        # Second argument
        ['"](?P<option>\S+)['"](,\s+
        (?:default=)?(?P<default>\S+?))?
    \)''', re.VERBOSE | re.MULTILINE)

configwithre = re.compile('''
    ui\.config(?P<ctype>with)\(
        # First argument is callback function. This doesn't parse robustly
        # if it is e.g. a function call.
        [^,]+,\s*
        ['"](?P<section>\S+)['"],\s*
        ['"](?P<option>\S+)['"](,\s+
        (?:default=)?(?P<default>\S+?))?
    \)''', re.VERBOSE | re.MULTILINE)

configpartialre = (r"""ui\.config""")

ignorere = re.compile(r'''
    \#\s(?P<reason>internal|experimental|deprecated|developer|inconsistent)\s
    config:\s(?P<config>\S+\.\S+)$
    ''', re.VERBOSE | re.MULTILINE)

def main(args):
    for f in args:
        sect = ''
        prevname = ''
        confsect = ''
        carryover = ''
        for l in open(f):

            # check topic-like bits
            m = re.match('\s*``(\S+)``', l)
            if m:
                prevname = m.group(1)
            if re.match('^\s*-+$', l):
                sect = prevname
                prevname = ''

            if sect and prevname:
                name = sect + '.' + prevname
                documented[name] = 1

            # check docstring bits
            m = re.match(r'^\s+\[(\S+)\]', l)
            if m:
                confsect = m.group(1)
                continue
            m = re.match(r'^\s+(?:#\s*)?(\S+) = ', l)
            if m:
                name = confsect + '.' + m.group(1)
                documented[name] = 1

            # like the bugzilla extension
            m = re.match(r'^\s*(\S+\.\S+)$', l)
            if m:
                documented[m.group(1)] = 1

            # like convert
            m = re.match(r'^\s*:(\S+\.\S+):\s+', l)
            if m:
                documented[m.group(1)] = 1

            # quoted in help or docstrings
            m = re.match(r'.*?``(\S+\.\S+)``', l)
            if m:
                documented[m.group(1)] = 1

            # look for ignore markers
            m = ignorere.search(l)
            if m:
                if m.group('reason') == 'inconsistent':
                    allowinconsistent.add(m.group('config'))
                else:
                    documented[m.group('config')] = 1

            # look for code-like bits
            line = carryover + l
            m = configre.search(line) or configwithre.search(line)
            if m:
                ctype = m.group('ctype')
                if not ctype:
                    ctype = 'str'
                name = m.group('section') + "." + m.group('option')
                default = m.group('default')
                if default in (None, 'False', 'None', '0', '[]', '""', "''"):
                    default = ''
                if re.match('[a-z.]+$', default):
                    default = '<variable>'
                if (name in foundopts and (ctype, default) != foundopts[name]
                    and name not in allowinconsistent):
                    print(l)
                    print("conflict on %s: %r != %r" % (name, (ctype, default),
                                                        foundopts[name]))
                foundopts[name] = (ctype, default)
                carryover = ''
            else:
                m = re.search(configpartialre, line)
                if m:
                    carryover = line
                else:
                    carryover = ''

    for name in sorted(foundopts):
        if name not in documented:
            if not (name.startswith("devel.") or
                    name.startswith("experimental.") or
                    name.startswith("debug.")):
                ctype, default = foundopts[name]
                if default:
                    default = ' [%s]' % default
                print("undocumented: %s (%s)%s" % (name, ctype, default))

if __name__ == "__main__":
    if len(sys.argv) > 1:
        sys.exit(main(sys.argv[1:]))
    else:
        sys.exit(main([l.rstrip() for l in sys.stdin]))