typeobject.c: Missing return -1 after PyErr_Format in type_ready_post_checks

[Wulian233]

Bug report

Bug description:

Parent issue #146102

https://gist.github.com/devdanzin/551cace22f112ef0ff4ed3fdbe54d235

At line 9314-9320, PyErr_Format sets a SystemError for invalid tp_dictoffset but falls through to return 0 (success). Type finishes initialization with invalid offset and pending exception. Requires C extension to trigger.

CPython versions tested on:

CPython main branch, 3.15, 3.14

Operating systems tested on:

No response

Linked PRs

• gh-148074: Fix typeobject.c missing error return #148075
• [3.14] gh-148074: Fix typeobject.c missing error return (GH-148075) #148095