diff --git a/hgext/remotefilelog/remotefilelog.py b/hgext/remotefilelog/remotefilelog.py
--- a/hgext/remotefilelog/remotefilelog.py
+++ b/hgext/remotefilelog/remotefilelog.py
@@ -324,7 +324,7 @@
         flags = store.getmeta(self.filename, node).get(constants.METAKEYFLAG, 0)
         if flags == 0:
             return rawtext
-        text, verifyhash = self._processflagsread(rawtext, flags)
+        text, verifyhash, sidedata = self._processflagsread(rawtext, flags)
         return text
 
     def rawdata(self, node):
diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -1663,7 +1663,8 @@
             validatehash = self._processflagsraw(rawtext, flags)
             text = rawtext
         else:
-            text, validatehash = self._processflagsread(rawtext, flags)
+            r = self._processflagsread(rawtext, flags)
+            text, validatehash, sidedata = r
         if validatehash:
             self.checkhash(text, node, rev=rev)
         if not validated:
diff --git a/mercurial/revlogutils/flagutil.py b/mercurial/revlogutils/flagutil.py
--- a/mercurial/revlogutils/flagutil.py
+++ b/mercurial/revlogutils/flagutil.py
@@ -118,7 +118,8 @@
         processed text and ``validatehash`` is a bool indicating whether the
         returned text should be checked for hash integrity.
         """
-        return self._processflagsfunc(text, flags, 'read')
+        text, vhash = self._processflagsfunc(text, flags, 'read')
+        return text, vhash, {}
 
     def _processflagswrite(self, text, flags):
         """Inspect revision data flags and applies write transformations defined
diff --git a/tests/simplestorerepo.py b/tests/simplestorerepo.py
--- a/tests/simplestorerepo.py
+++ b/tests/simplestorerepo.py
@@ -294,7 +294,8 @@
             validatehash = self._processflagsraw(rawtext, flags)
             text = rawtext
         else:
-            text, validatehash = self._processflagsread(rawtext, flags)
+            r = self._processflagsread(rawtext, flags)
+            text, validatehash, sidedata = r
         if validatehash:
             self.checkhash(text, node, rev=rev)