--- a/tests/flagprocessorext.py	Sat May 22 00:06:22 2021 +0200
+++ b/tests/flagprocessorext.py	Sun May 30 16:19:36 2021 +0200
@@ -13,6 +13,7 @@
     util,
 )
 from mercurial.revlogutils import flagutil
+from mercurial.interfaces import repository
 
 # Test only: These flags are defined here only in the context of testing the
 # behavior of the flag processor. The canonical way to add flags is to get in
@@ -131,6 +132,7 @@
     # Teach revlog about our test flags
     flags = [REVIDX_NOOP, REVIDX_BASE64, REVIDX_GZIP, REVIDX_FAIL]
     flagutil.REVIDX_KNOWN_FLAGS |= util.bitsfrom(flags)
+    repository.REVISION_FLAGS_KNOWN |= util.bitsfrom(flags)
     revlog.REVIDX_FLAGS_ORDER.extend(flags)
 
     # Teach exchange to use changegroup 3