diff -r 576040155dba -r e845537f6adb mercurial/localrepo.py
--- a/mercurial/localrepo.py	Wed Jan 26 15:32:18 2022 -0800
+++ b/mercurial/localrepo.py	Wed Feb 02 17:24:05 2022 +0100
@@ -1190,7 +1190,7 @@
             b"fast implementation."
         )
         hint = _(
-            b"check `hg help config.format.exp-rc-dirstate-v2` " b"for details"
+            b"check `hg help config.format.use-dirstate-v2` " b"for details"
         )
         if not dirstate.HAS_FAST_DIRSTATE_V2:
             if slow_path == b'warn':
@@ -2824,6 +2824,8 @@
                 self.ui.debug(b'updating the branch cache\n')
                 self.filtered(b'served').branchmap()
                 self.filtered(b'served.hidden').branchmap()
+                # flush all possibly delayed write.
+                self._branchcaches.write_delayed(self)
 
         if repository.CACHE_CHANGELOG_CACHE in caches:
             self.changelog.update_caches(transaction=tr)
@@ -3618,9 +3620,9 @@
         if ui.configbool(b'format', b'sparse-revlog'):
             requirements.add(requirementsmod.SPARSEREVLOG_REQUIREMENT)
 
-    # experimental config: format.exp-rc-dirstate-v2
+    # experimental config: format.use-dirstate-v2
     # Keep this logic in sync with `has_dirstate_v2()` in `tests/hghave.py`
-    if ui.configbool(b'format', b'exp-rc-dirstate-v2'):
+    if ui.configbool(b'format', b'use-dirstate-v2'):
         requirements.add(requirementsmod.DIRSTATE_V2_REQUIREMENT)
 
     # experimental config: format.exp-use-copies-side-data-changeset