diff --git a/mercurial/dagutil.py b/mercurial/dagutil.py
--- a/mercurial/dagutil.py
+++ b/mercurial/dagutil.py
@@ -148,7 +148,7 @@
                     if (r is not None
                         and r != nullrev
                         and r not in rl.filteredrevs)]
-        return map(self._internalize, ids)
+        return [self._internalize(i) for i in ids]
 
 
 class revlogdag(revlogbaseddag):