diff --git a/hggit/overlay.py b/hggit/overlay.py
index aa8519daf037d63cb6fb8b9a7387dea4c6f08973_aGdnaXQvb3ZlcmxheS5weQ==..c99941ff2d287d2b1d76ceab4b3881974ede5f7c_aGdnaXQvb3ZlcmxheS5weQ== 100644
--- a/hggit/overlay.py
+++ b/hggit/overlay.py
@@ -192,6 +192,9 @@
             return self.base.parents(n)
         commit = self.repo.handler.git.get_object(_maybehex(n))
 
+        if not commit.parents:
+            return [nullid, nullid]
+
         def gitorhg(n):
             hn = self.repo.handler.map_hg_get(hex(n))
             if hn is not None:
diff --git a/tests/test-incoming.t b/tests/test-incoming.t
old mode 100755
new mode 100644
index aa8519daf037d63cb6fb8b9a7387dea4c6f08973_dGVzdHMvdGVzdC1pbmNvbWluZy50..c99941ff2d287d2b1d76ceab4b3881974ede5f7c_dGVzdHMvdGVzdC1pbmNvbWluZy50
--- a/tests/test-incoming.t
+++ b/tests/test-incoming.t
@@ -9,6 +9,15 @@
   $ fn_git_commit -m "add alpha"
 
   $ cd ..
+  $ hg init hgrepo-empty
+  $ hg -R hgrepo-empty incoming gitrepo | grep -v 'no changes found' | grep -v 'bookmark:'
+  comparing with gitrepo
+  changeset:   0:7eeab2ea75ec
+  user:        test <test@example.org>
+  date:        Mon Jan 01 00:00:10 2007 +0000
+  summary:     add alpha
+  
+
   $ hg clone gitrepo hgrepo | grep -v '^updating'
   importing git objects into hg
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved