hgext/children.py

localrepo.commit: grab locks before getting the list of files to commit

Somebody may change the dirstate after we've determined the parents of
the working dir and run repo.status, but before we called wlock().

This should also fix issue997, where backout would change a file without
changing its size and then call repo.commit without passing the list of
files. If this happened in less than one second, we wouldn't detect any
file changes - the in-memory dirstate still has the cached stat data for
that file. Grabbing the wlock early causes the dirstate to be
invalidated and we end up reading the dirstate file again, which has
that file marked for lookup (size == -1).

A better fix would be for backout to give repo.commit the exact list of
files, but that'll require some changes to the revert operation.

A significant user-visible change is that the precommit hook is always
run with both locks grabbed - previously, hg commit would run it before
grabbing any locks, but hg import would run it after grabbing locks.

# Mercurial extension to provide the 'hg children' command
#
# Copyright 2007 by Intevation GmbH <[e-mail]>
# Author(s):
# Thomas Arendsen Hein <[e-mail]>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

from mercurial import cmdutil
from mercurial.commands import templateopts
from mercurial.i18n import _


def children(ui, repo, file_=None, **opts):
    """show the children of the given or working dir revision

    Print the children of the working directory's revisions.
    If a revision is given via --rev, the children of that revision
    will be printed. If a file argument is given, revision in
    which the file was last changed (after the working directory
    revision or the argument to --rev if given) is printed.
    """
    rev = opts.get('rev')
    if file_:
        ctx = repo.filectx(file_, changeid=rev)
    else:
        ctx = repo.changectx(rev)

    displayer = cmdutil.show_changeset(ui, repo, opts)
    for node in [cp.node() for cp in ctx.children()]:
        displayer.show(changenode=node)


cmdtable = {
    "children":
        (children,
         [('r', 'rev', '', _('show children of the specified rev')),
         ] + templateopts,
         _('hg children [-r REV] [FILE]')),
}