revlog: signal which revlog index are compatible with Rust Otherwise, Rust may treat python object like `cindex` object, leading to trouble. The new attribute is an integer because I expect we might need a flag field in the future. As a start we get the rust code to raise a clear TypeError. We will use the information in a smarter way in the next changesets. Differential Revision: https://phab.mercurial-scm.org/D10665

--- a/mercurial/policy.py	Tue May 04 11:19:48 2021 +0200
+++ b/mercurial/policy.py	Tue May 04 14:16:26 2021 +0200
@@ -80,7 +80,7 @@
     ('cext', 'bdiff'): 3,
     ('cext', 'mpatch'): 1,
     ('cext', 'osutil'): 4,
-    ('cext', 'parsers'): 19,
+    ('cext', 'parsers'): 20,
 }
 
 # map import request to other package or module