--- a/mercurial/exchangev2.py	Fri Jan 15 01:58:59 2021 +0100
+++ b/mercurial/exchangev2.py	Wed Jan 20 14:47:13 2021 +0100
@@ -423,6 +423,7 @@
         iterrevisions(),
         linkrev,
         weakref.proxy(tr),
+        alwayscache=True,
         addrevisioncb=onchangeset,
         duplicaterevisioncb=ondupchangeset,
     )