René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Crash when using multiple capturing groups in `re.Scanner`","articleBody":"# Bug report\n\n### Bug description:\n\nThe re.Scanner class crashes with a segmentation fault (memory corruption) when any pattern in the lexicon contains named capturing groups. \n\n```python\nimport re\n\nlexicon = [\n    ('(?P\u003cgroup1\u003ea)(?P\u003cgroup2\u003eb)', None),  # Named capturing groups\n]\n\nscanner = re.Scanner(lexicon)\nresult, leftover = scanner.scan(\"ab\")  # Segmentation fault occurs here\n```\n\n```python\nzsh: segmentation fault  python3 test.py\n```\n\nScanner should process the input normally and return scan results without crashing, but Python interpreter crashes with segmentation fault, indicating memory corruption.\n\n### CPython versions tested on:\n\n3.12\n\n### Operating systems tested on:\n\nLinux\n\n\u003c!-- gh-linked-prs --\u003e\n### Linked PRs\n* gh-140944\n* gh-140982\n* gh-140983\n* gh-140984\n* gh-142231\n* gh-142309\n\u003c!-- /gh-linked-prs --\u003e\n","author":{"url":"https://github.com/T90REAL","@type":"Person","name":"T90REAL"},"datePublished":"2025-10-30T15:48:25.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":28},"url":"https://github.com/140797/cpython/issues/140797"}