diff --git a/hgext/remotefilelog/remotefilelog.py b/hgext/remotefilelog/remotefilelog.py
--- a/hgext/remotefilelog/remotefilelog.py
+++ b/hgext/remotefilelog/remotefilelog.py
@@ -129,7 +129,7 @@
         return data
 
     def addrevision(self, text, transaction, linknode, p1, p2, cachedelta=None,
-                    node=None, flags=revlog.REVIDX_DEFAULT_FLAGS):
+                    node=None, flags=revlog.REVIDX_DEFAULT_FLAGS, sidedata=()):
         # text passed to "addrevision" includes hg filelog metadata header
         if node is None:
             node = storageutil.hashrevisionsha1(text, p1, p2)
diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -1816,7 +1816,8 @@
         """
 
     def addrevision(self, text, transaction, link, p1, p2, cachedelta=None,
-                    node=None, flags=REVIDX_DEFAULT_FLAGS, deltacomputer=None):
+                    node=None, flags=REVIDX_DEFAULT_FLAGS, deltacomputer=None,
+                    sidedata=None):
         """add a revision to the log
 
         text - the revision data to add
@@ -1835,6 +1836,9 @@
             raise error.RevlogError(_("attempted to add linkrev -1 to %s")
                                     % self.indexfile)
 
+        if sidedata is None:
+            sidedata = {}
+
         if flags:
             node = node or self.hash(text, p1, p2)