--- a/hgext3rd/evolve/stablesort.py	Thu Dec 21 06:18:50 2017 +0100
+++ b/hgext3rd/evolve/stablesort.py	Thu Dec 21 06:12:02 2017 +0100
@@ -338,8 +338,8 @@
 
     def getjumps(self, repo, rev):
         if not self._hasjumpsdata(rev):
-            parents = repo.changelog.parentrevs(rev)
-            if parents[1] == nodemod.nullrev:
+            parents = filterparents(repo.changelog.parentrevs(rev))
+            if len(parents) <= 1:
                 self._setjumps(rev, None)
             else:
                 # merge ! warn the cache
@@ -585,8 +585,8 @@
 
         progress(0, '')
         for idx, rev in enumerate(data):
-            parents = repo.changelog.parentrevs(rev)
-            if parents[1] == nodemod.nullrev:
+            parents = filterparents(repo.changelog.parentrevs(rev))
+            if len(parents) <= 1:
                 self._setjumps(rev, None)
             else:
                 # merge! warn the cache