--- a/mercurial/cmdutil.py	Sat Nov 28 04:11:38 2015 -0500
+++ b/mercurial/cmdutil.py	Sat Nov 28 04:11:57 2015 -0500
@@ -2619,6 +2619,11 @@
                 message = old.description()
 
             pureextra = extra.copy()
+            if 'amend_source' in pureextra:
+                del pureextra['amend_source']
+            pureoldextra = old.extra()
+            if 'amend_source' in pureoldextra:
+                del pureoldextra['amend_source']
             extra['amend_source'] = old.hex()
 
             new = context.memctx(repo,
@@ -2636,7 +2641,7 @@
                 and newdesc == old.description()
                 and user == old.user()
                 and date == old.date()
-                and pureextra == old.extra()):
+                and pureextra == pureoldextra):
                 # nothing changed. continuing here would create a new node
                 # anyway because of the amend_source noise.
                 #