# HG changeset patch
# User Pierre-Yves David <pierre-yves.david@octobus.net>
# Date 2024-03-11 00:20:12
# Node ID d54f0692820d649eb193d284412efe778e9ad17b
# Parent  4188a0570ba17e96257eb84d6b556398f3c5c5a5

repoview: prevent `None` to be passed as the filtername

We let such instantiation slip in a previous commit, so we add an explicit check
to prevent it to happen in the future.

diff --git a/mercurial/repoview.py b/mercurial/repoview.py
--- a/mercurial/repoview.py
+++ b/mercurial/repoview.py
@@ -397,6 +397,9 @@ class repoview:
     """
 
     def __init__(self, repo, filtername, visibilityexceptions=None):
+        if filtername is None:
+            msg = "repoview should have a non-None filtername"
+            raise error.ProgrammingError(msg)
         object.__setattr__(self, '_unfilteredrepo', repo)
         object.__setattr__(self, 'filtername', filtername)
         object.__setattr__(self, '_clcachekey', None)