diff --git a/mercurial/repo.py b/mercurial/repo.py
new file mode 100644
--- /dev/null
+++ b/mercurial/repo.py
@@ -0,0 +1,8 @@
+# repo.py - repository base classes for mercurial
+#
+# Copyright 2005 Matt Mackall <mpm@selenic.com>
+#
+# This software may be used and distributed according to the terms
+# of the GNU General Public License, incorporated herein by reference.
+
+class RepoError(Exception): pass