diff --git a/mercurial/cmdutil.py b/mercurial/cmdutil.py
--- a/mercurial/cmdutil.py
+++ b/mercurial/cmdutil.py
@@ -1210,6 +1210,7 @@ def walkchangerevs(ui, repo, match, opts
                 return rev in wanted
 
         for i, window in increasing_windows(0, len(revs)):
+            change = util.cachefunc(repo.changectx)
             nrevs = [rev for rev in revs[i:i+window] if want(rev)]
             for rev in sorted(nrevs):
                 fns = fncache.get(rev)