--- a/mercurial/copies.py	Wed Dec 27 19:49:36 2017 -0800
+++ b/mercurial/copies.py	Wed Dec 27 22:05:20 2017 -0800
@@ -162,8 +162,8 @@
 
 def usechangesetcentricalgo(repo):
     """Checks if we should use changeset-centric copy algorithms"""
-    return (repo.ui.config('experimental', 'copies.read-from') ==
-            'compatibility')
+    return (repo.ui.config('experimental', 'copies.read-from') in
+            ('changeset-only', 'compatibility'))
 
 def _committedforwardcopies(a, b, match):
     """Like _forwardcopies(), but b.rev() cannot be None (working copy)"""