diff -r 0fc95f5cea57 -r c20688b7c061 mercurial/setdiscovery.py
--- a/mercurial/setdiscovery.py	Tue Aug 30 14:18:58 2011 +0200
+++ b/mercurial/setdiscovery.py	Thu Aug 25 21:25:14 2011 +0200
@@ -41,7 +41,7 @@
 def _setupsample(dag, nodes, size):
     if len(nodes) <= size:
         return set(nodes), None, 0
-    always = set(dag.heads())
+    always = dag.headsetofconnecteds(nodes)
     desiredlen = size - len(always)
     if desiredlen <= 0:
         # This could be bad if there are very many heads, all unknown to the