view contrib/simplemerge @ 24992:7df090c9c9fe

localrepo: use changelog.hasnode instead of self.__contains__

Before this patch, releasing the store lock implies the actions below, when
the transaction is aborted:

  1. "commithook()" scheduled in "localrepository.commit()" is invoked
  2. "changectx.__init__()" is invoked via "self.__contains__()"
  3. specified ID is examined against "repo.dirstate.p1()"
  4. validation function is invoked in "dirstate.p1()"

In subsequent patches, "dirstate.invalidate()" invocations for
discarding changes are replaced with "dirstateguard", but discarding
changes by "dirstateguard" is executed after releasing the store lock:
resources are acquired in "wlock => dirstateguard => store lock" order,
and are released in reverse order.

This may cause that "dirstate.p1()" still refers to the changeset to be
rolled-back at (4) above: pushing multiple patches by "hg qpush" is
a typical case.

When releasing the store lock, such changesets are:

  - not contained in "repo.changelog", if it is reloaded from
    ".hg/00changelog.i", as that file was already truncated by
    "transaction.abort()"

  - still contained in it, otherwise
    (this "dirty read" problem is discussed in "Transaction Plan"
     http://mercurial.selenic.com/wiki/TransactionPlan)

Validation function shows "unknown working parent" warning in the
former case, but reloading "repo.changelog" depends on the timestamp
of ".hg/00changelog.i". This causes occasional test failures.

In the case of scheduled "commithook()", it just wants to examine
whether "node ID" of committed changeset is still valid or not. Other
examinations implied in "changectx.__init__()" are meaningless.

To avoid showing the "unknown working parent" warning irregularly, this
patch uses "changelog.hasnode()" instead of "node in self" to examine
existence of committed changeset.

#!/usr/bin/env python

from mercurial import demandimport
demandimport.enable()

import sys
from mercurial.i18n import _
from mercurial import 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 fancyopts.getopt.GetoptError, 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(), *args, **opts))
except ParseError, e:
    sys.stdout.write("%s: %s\n" % (sys.argv[0], e))
    showhelp()
    sys.exit(1)
except util.Abort, e:
    sys.stderr.write("abort: %s\n" % e)
    sys.exit(255)
except KeyboardInterrupt:
    sys.exit(255)