diff --git a/mercurial/graphmod.py b/mercurial/graphmod.py
--- a/mercurial/graphmod.py
+++ b/mercurial/graphmod.py
@@ -48,9 +48,6 @@ def dagwalker(repo, revs):
     returned.
 
     """
-    if not revs:
-        return
-
     gpcache = {}
 
     for rev in revs: