# HG changeset patch
# User Pierre-Yves David <pierre-yves.david@octobus.net>
# Date 2021-07-19 20:19:36
# Node ID aa2296893168f36ede481713c6123afd6dfa86ce
# Parent  f030c7d220326e315c146bb5821b5e280fcd312e

upgrade: avoid a traceback in case of unrecognized revlog

Without this, in case of revlog name not matching any know pattern we would get
a traceback. Raising a clear error seems simpler.

Differential Revision: https://phab.mercurial-scm.org/D11202

diff --git a/mercurial/upgrade_utils/engine.py b/mercurial/upgrade_utils/engine.py
--- a/mercurial/upgrade_utils/engine.py
+++ b/mercurial/upgrade_utils/engine.py
@@ -64,7 +64,12 @@ def _revlogfrompath(repo, rl_type, path)
         )
     else:
         # drop the extension and the `data/` prefix
-        path = path.rsplit(b'.', 1)[0].split(b'/', 1)[1]
+        path_part = path.rsplit(b'.', 1)[0].split(b'/', 1)
+        if len(path_part) < 2:
+            msg = _('cannot recognize revlog from filename: %s')
+            msg %= path
+            raise error.Abort(msg)
+        path = path_part[1]
         return filelog.filelog(repo.svfs, path)