--- a/mercurial/bundlerepo.py	Sat Jan 28 18:26:28 2023 +0400
+++ b/mercurial/bundlerepo.py	Mon Jan 30 18:25:11 2023 -0500
@@ -533,6 +533,8 @@
     try:
         repo = localrepo.instance(ui, repopath, create=False)
         tempparent = None
+    except error.RequirementError:
+        raise  # no fallback if the backing repo is unsupported
     except error.RepoError:
         tempparent = pycompat.mkdtemp()
         try: