--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hgext3rd/topic/discovery.py	Thu Mar 17 09:12:18 2016 -0700
@@ -0,0 +1,106 @@
+import weakref
+from mercurial import branchmap
+from mercurial import error
+from mercurial import exchange
+from mercurial.i18n import _
+from . import topicmap
+
+def _headssummary(orig, repo, remote, outgoing):
+    publishing = ('phases' not in remote.listkeys('namespaces')
+                  or bool(remote.listkeys('phases').get('publishing', False)))
+    if publishing:
+        return orig(repo, remote, outgoing)
+    oldgetitem = repo.__getitem__
+    oldrepo = repo.__class__
+    oldbranchcache = branchmap.branchcache
+    oldfilename = branchmap._filename
+    try:
+        class repocls(repo.__class__):
+            def __getitem__(self, key):
+                ctx = super(repocls, self).__getitem__(key)
+                oldbranch = ctx.branch
+                def branch():
+                    branch = oldbranch()
+                    topic = ctx.topic()
+                    if topic:
+                        branch = "%s:%s" % (branch, topic)
+                    return branch
+                ctx.branch = branch
+                return ctx
+        repo.__class__ = repocls
+        branchmap.branchcache = topicmap.topiccache
+        branchmap._filename = topicmap._filename
+        summary = orig(repo, remote, outgoing)
+        for key, value in summary.iteritems():
+            if ':' in key: # This is a topic
+                if value[0] is None and value[1]:
+                    summary[key] = ([value[1].pop(0)], ) + value[1:]
+        return summary
+    finally:
+        repo.__class__ = oldrepo
+        branchmap.branchcache = oldbranchcache
+        branchmap._filename = oldfilename
+
+def wireprotobranchmap(orig, repo, proto):
+    oldrepo = repo.__class__
+    try:
+        class repocls(repo.__class__):
+            def branchmap(self):
+                usetopic = not self.publishing()
+                return super(repocls, self).branchmap(topic=usetopic)
+        repo.__class__ = repocls
+        return orig(repo, proto)
+    finally:
+        repo.__class__ = oldrepo
+
+
+# Discovery have deficiency around phases, branch can get new heads with pure
+# phases change. This happened with a changeset was allowed to be pushed
+# because it had a topic, but it later become public and create a new branch
+# head.
+#
+# Handle this by doing an extra check for new head creation server side
+def _nbheads(repo):
+    data = {}
+    for b in repo.branchmap().iterbranches():
+        if ':' in b[0]:
+            continue
+        data[b[0]] = len(b[1])
+    return data
+
+def handlecheckheads(orig, op, inpart):
+    orig(op, inpart)
+    if op.repo.publishing():
+        return
+    tr = op.gettransaction()
+    if tr.hookargs['source'] not in ('push', 'serve'): # not a push
+        return
+    tr._prepushheads = _nbheads(op.repo)
+    reporef = weakref.ref(op.repo)
+    oldvalidator = tr.validator
+    def validator(tr):
+        repo = reporef()
+        if repo is not None:
+            repo.invalidatecaches()
+            finalheads = _nbheads(repo)
+            for branch, oldnb in tr._prepushheads.iteritems():
+                newnb = finalheads.pop(branch, 0)
+                if oldnb < newnb:
+                    msg = _('push create a new head on branch "%s"' % branch)
+                    raise error.Abort(msg)
+            for branch, newnb in finalheads.iteritems():
+                if 1 < newnb:
+                    msg = _('push create more than 1 head on new branch "%s"' % branch)
+                    raise error.Abort(msg)
+        return oldvalidator(tr)
+    tr.validator = validator
+handlecheckheads.params = frozenset()
+
+def _pushb2phases(orig, pushop, bundler):
+    hascheck =  any(p.type == 'check:heads' for p in  bundler._parts)
+    if pushop.outdatedphases and not hascheck:
+        exchange._pushb2ctxcheckheads(pushop, bundler)
+    return orig(pushop, bundler)
+
+
+