mercurial/upgrade.py

--- a/mercurial/upgrade.py	Thu Sep 20 19:20:01 2018 -0700
+++ b/mercurial/upgrade.py	Mon Sep 24 09:38:27 2018 -0700
@@ -491,10 +491,7 @@
         for path in rl.files():
             datasize += rl.opener.stat(path).st_size
 
-        idx = rl.index
-        for rev in rl:
-            e = idx[rev]
-            rawsize += e[2]
+        rawsize += sum(map(rl.rawsize, iter(rl)))
 
         srcsize += datasize
         srcrawsize += rawsize