diff --git a/hgext/git/gitlog.py b/hgext/git/gitlog.py
--- a/hgext/git/gitlog.py
+++ b/hgext/git/gitlog.py
@@ -96,6 +96,10 @@ class baselogindex(object):
 
 # TODO: an interface for the changelog type?
 class changelog(baselog):
+    # TODO: this appears to be an enumerated type, and should probably
+    # be part of the public changelog interface
+    _copiesstorage = b'extra'
+
     def __contains__(self, rev):
         try:
             self.node(rev)