--- a/mercurial/pure/parsers.py	Wed Jun 19 17:03:13 2024 +0200
+++ b/mercurial/pure/parsers.py	Wed Jun 19 19:10:49 2024 +0200
@@ -672,6 +672,9 @@
             r = (offset,) + r[1:]
         return r
 
+    def __delitem__(self, i):
+        raise NotImplementedError()
+
     def _unpack_entry(self, rev, data):
         r = self.index_format.unpack(data)
         r = r + (