--- a/mercurial/setdiscovery.py	Sun Mar 04 13:04:12 2018 -0500
+++ b/mercurial/setdiscovery.py	Sun Mar 04 07:37:08 2018 -0800
@@ -130,7 +130,7 @@
         sample = set(random.sample(sample, desiredlen))
     return sample
 
-def findcommonheads(ui, local, remote, heads=None,
+def findcommonheads(ui, local, remote,
                     initialsamplesize=100,
                     fullsamplesize=200,
                     abortwhenunrelated=True,
@@ -155,15 +155,11 @@
     sample = _limitsample(ownheads, initialsamplesize)
     # indices between sample and externalized version must match
     sample = list(sample)
-    if heads:
-        srvheadhashes = heads
-        yesno = remote.known(dag.externalizeall(sample))
-    else:
-        batch = remote.iterbatch()
-        batch.heads()
-        batch.known(dag.externalizeall(sample))
-        batch.submit()
-        srvheadhashes, yesno = batch.results()
+    batch = remote.iterbatch()
+    batch.heads()
+    batch.known(dag.externalizeall(sample))
+    batch.submit()
+    srvheadhashes, yesno = batch.results()
 
     if cl.tip() == nullid:
         if srvheadhashes != [nullid]: