contrib/simplemerge

repovfs: add a ward to check if locks are properly taken

When the appropriate developer warnings are enabled, We wrap 'repo.vfs.audit' to
check for locks when accessing file in '.hg' for writing. Another changeset will
add a 'ward' for the store vfs (svfs).

This check system has caught a handful of locking issues that have been fixed
in previous series (mostly in 4.0). I expect another batch to be caught in third
party extensions.

We introduce two real exceptions from extensions 'blackbox.log' (because a lot of
read-only operations add entry to it), and 'last-email.txt' (because 'hg email'
is currently a read only operation and there is value to keep it this way).

In addition we are currently allowing bisect to operate outside of the lock
because the current code is a bit hard to get properly locked for now. Multiple
clean up have been made but there is still a couple of them to do and the freeze
is coming.

#!/usr/bin/env python

from mercurial import demandimport
demandimport.enable()

import getopt
import sys
from mercurial.i18n import _
from mercurial import error, simplemerge, fancyopts, util, ui

options = [('L', 'label', [], _('labels to use on conflict markers')),
           ('a', 'text', None, _('treat all files as text')),
           ('p', 'print', None,
            _('print results instead of overwriting LOCAL')),
           ('', 'no-minimal', None, _('no effect (DEPRECATED)')),
           ('h', 'help', None, _('display help and exit')),
           ('q', 'quiet', None, _('suppress output'))]

usage = _('''simplemerge [OPTS] LOCAL BASE OTHER

    Simple three-way file merge utility with a minimal feature set.

    Apply to LOCAL the changes necessary to go from BASE to OTHER.

    By default, LOCAL is overwritten with the results of this operation.
''')

class ParseError(Exception):
    """Exception raised on errors in parsing the command line."""

def showhelp():
    sys.stdout.write(usage)
    sys.stdout.write('\noptions:\n')

    out_opts = []
    for shortopt, longopt, default, desc in options:
        out_opts.append(('%2s%s' % (shortopt and '-%s' % shortopt,
                                    longopt and ' --%s' % longopt),
                         '%s' % desc))
    opts_len = max([len(opt[0]) for opt in out_opts])
    for first, second in out_opts:
        sys.stdout.write(' %-*s  %s\n' % (opts_len, first, second))

try:
    for fp in (sys.stdin, sys.stdout, sys.stderr):
        util.setbinary(fp)

    opts = {}
    try:
        args = fancyopts.fancyopts(sys.argv[1:], options, opts)
    except getopt.GetoptError as e:
        raise ParseError(e)
    if opts['help']:
        showhelp()
        sys.exit(0)
    if len(args) != 3:
            raise ParseError(_('wrong number of arguments'))
    sys.exit(simplemerge.simplemerge(ui.ui.load(), *args, **opts))
except ParseError as e:
    sys.stdout.write("%s: %s\n" % (sys.argv[0], e))
    showhelp()
    sys.exit(1)
except error.Abort as e:
    sys.stderr.write("abort: %s\n" % e)
    sys.exit(255)
except KeyboardInterrupt:
    sys.exit(255)