René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"untokenize() round-trip fails for t-strings (with only type + string)","articleBody":"# Bug report\n\n### Bug description:\n\nFound when investigating [test.test_tokenize.TestRoundtrip.test_random_files](https://github.com/python/cpython/actions/runs/15209215387/job/42779254060?pr=134577#step:22:490)  failing on #134577\n\n```python\ndef test(code):\n    tokens = list(tokenize.tokenize(iter([code]).__next__))\n    from5 = tokenize.untokenize(tokens)\n    print(\"from5   \", from5, eval(from5))\n\n    tokens2 = [tok[:2] for tok in tokens]\n    from2 = tokenize.untokenize(tokens2)\n    print(\"from2   \", from2, eval(from2))\n```\n\n```pycon\n\u003e\u003e\u003e test(b't\"{ {} }\"')\nfrom5    b't\"{ {} }\"' Template(strings=('', ''), interpolations=(Interpolation({}, ' {}', None, ''),))\nfrom2    b't\"{{}}\"'   Template(strings=('{}',), interpolations=())\n\n\u003e\u003e\u003e test(b'f\"{ {} }\"')\nfrom5    b'f\"{ {} }\"' {}\nfrom2    b'f\"{ {} }\"' {}\n```\n\nFrom what I understand, [untokenize](https://docs.python.org/3/library/tokenize.html#tokenize.untokenize) should round-trip correctly even with only the type and string of tokens.\n\n### CPython versions tested on:\n\nCPython main branch\n\n### Operating systems tested on:\n\nmacOS\n\n\u003c!-- gh-linked-prs --\u003e\n### Linked PRs\n* gh-134603\n* gh-134659\n\u003c!-- /gh-linked-prs --\u003e\n","author":{"url":"https://github.com/loic-simon","@type":"Person","name":"loic-simon"},"datePublished":"2025-05-23T12:43:51.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/134582/cpython/issues/134582"}