hgext/children.py

fix pull racing with push/commit (issue1320)

changegroup() has a problem when nodes which does not descend from a node
in <bases> are added to remote after the discovery phase.
If that happens, changegroup() won't send the correct set of nodes, ie.
some nodes will be missing.
To correct it we have to find the set of nodes that both remote and self
have (called <common>), and send all the nodes not in <common>.

This fix has some overhead, in the worst case it will re-send a whole branch.

A proper fix to avoid this overhead might be to change the protocol so that
the <common> nodes are sent (instead of the <bases> of the missing nodes).

# 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[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]')),
}