+
−from mercurial import error
+
−from mercurial import util
+
−from mercurial import destutil
+
−from mercurial import extensions
+
−from mercurial.i18n import _
+
−
+
−def _destmergebranch(orig, repo):
+
−    p1 = repo['.']
+
−    top = p1.topic()
+
−    if top:
+
−        heads = repo.revs('heads(topic(.)::topic(.))')
+
−        if p1.rev() not in heads:
+
−            raise error.Abort(_("not at topic head, update or explicit"))
+
−        elif 1 == len(heads):
+
−            # should look at all branch involved but... later
+
−            bhead = ngtip(repo, p1.branch(), all=True)
+
−            if not bhead:
+
−                raise error.Abort(_("nothing to merge"))
+
−            elif 1 == len(bhead):
+
−                return bhead.first()
+
−            else:
+
−                raise error.Abort(_("branch '%s' has %d heads - "
+
−                                   "please merge with an explicit rev")
+
−                                 % (p1.branch(), len(bhead)),
+
−                                 hint=_("run 'hg heads .' to see heads"))
+
−        elif 2 == len(heads):
+
−            heads = [r for r in heads if r != p1.rev()]
+
−            # XXX: bla bla bla bla bla
+
−            if 1 < len(heads):
+
−                raise error.Abort(_('working directory not at a head revision'),
+
−                                 hint=_("use 'hg update' or merge with an "
+
−                                        "explicit revision"))
+
−            return heads[0]
+
−        elif 2 < len(heads):
+
−            raise error.Abort(_("topic '%s' has %d heads - "
+
−                                "please merge with an explicit rev")
+
−                              % (top, len(heads)))
+
−        else:
+
−            assert False # that's impossible
+
−    return orig(repo)
+
−
+
−def setupdest():
+
−    if util.safehasattr(destutil, '_destmergebranch'):
+
−        extensions.wrapfunction(destutil, '_destmergebranch', _destmergebranch)
+
−
+
−def ngtip(repo, branch, all=False):
+
−    """tip new generation"""
+
−    ## search for untopiced heads of branch
+
−    # could be heads((::branch(x) - topic()))
+
−    # but that is expensive
+
−    #
+
−    # we should write plain code instead
+
−    subquery = '''heads(
+
−                    parents(
+
−                       ancestor(
+
−                         (head() and branch(%s)
+
−                         or (topic() and branch(%s)))))
+
−                   ::(head() and branch(%s))
+
−                   - topic())'''
+
−    if not all:
+
−        subquery = 'max(%s)' % subquery
+
−    return repo.revs(subquery, branch, branch, branch)