[PATCH 5 of 6] obsolete: add an any successors funtion

[pierre-yves.david at logilab.fr]

# HG changeset patch
# User Pierre-Yves David <pierre-yves.david at logilab.fr>
# Date 1342539089 -7200
# Node ID e684aa58b85911fa1f6f8f0f9571a8b191bf6a3d
# Parent  34404576fe9a255c4329b536572a9d325135e363
obsolete: add an any successors funtion

This function yield every nodes which succeed to a group of nodes.

The first user will be checkheads who need to know if we push successors for
remote extra heads.

diff --git a/mercurial/obsolete.py b/mercurial/obsolete.py
--- a/mercurial/obsolete.py
+++ b/mercurial/obsolete.py
@@ -283,5 +283,19 @@ def precursormarkers(ctx):
 def successormarkers(ctx):
     """obsolete marker marking this changeset as a successors"""
     for data in ctx._repo.obsstore.successors.get(ctx.node(), ()):
         yield marker(ctx._repo, data)
 
+def anysuccessors(obsstore, node):
+    """Yield every successors of <node>
+
+    This this a linear yield unsuitable to detect splitted changeset."""
+    remaining = set([node])
+    seen = set(remaining)
+    while remaining:
+        current = remaining.pop()
+        yield current
+        for mark in obsstore.precursors.get(current, ()):
+            for suc in mark[1]:
+                if suc not in seen:
+                    seen.add(suc)
+                    remaining.add(suc)