René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Python 3.12.0a7 can fail to catch exceptions when an iterator is involved","articleBody":"# Bug report\r\n\r\nPython 3.12.0a7 (at least as of commit d65ed693a8a13a2a7f9b201bda1224d6ae5fcf0e) can fail to catch exceptions when an iterator is involved. The following code works on Python 3.11 but the `ValueError` is uncaught on Python 3.12:\r\n\r\n```python\r\n#!/usr/bin/env python\r\n\r\ndef do_work():\r\n    yield\r\n    raise ValueError()\r\n\r\n\r\ndef main():\r\n    try:\r\n        for _ in do_work():\r\n            if True is False:\r\n                return\r\n    except ValueError:\r\n        pass\r\n\r\n\r\nif __name__ == '__main__':\r\n    main()\r\n```\r\n\r\nWith this code in `repro.py` the following traceback is shown on Python 3.12:\r\n\r\n```\r\nTraceback (most recent call last):\r\n  File \"//repro.py\", line 18, in \u003cmodule\u003e\r\n    main()\r\n  File \"//repro.py\", line 12, in main\r\n    return\r\n  File \"//repro.py\", line 5, in do_work\r\n    raise ValueError()\r\nValueError\r\n```\r\n\r\nNo error or output occurs under Python 3.11.\r\n\r\n# Your environment\r\n\r\nTested on Ubuntu 20.04.5 using the deadsnakes nightly build: python3.12 - 3.12.0~a7-98-gd65ed693a8-1+focal1 \r\n\n\n\u003c!-- gh-linked-prs --\u003e\n### Linked PRs\n* gh-103502\n\u003c!-- /gh-linked-prs --\u003e\n","author":{"url":"https://github.com/mattclay","@type":"Person","name":"mattclay"},"datePublished":"2023-04-12T21:32:02.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":14},"url":"https://github.com/103488/cpython/issues/103488"}