diff -r 9d62f9fa332f -r a45d670c2bfc mercurial/revlog.py
--- a/mercurial/revlog.py	Tue Sep 03 22:36:41 2019 +0200
+++ b/mercurial/revlog.py	Tue Sep 03 22:55:04 2019 +0200
@@ -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: