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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"t-strings: AST unparsing does not reproduce original formatting","articleBody":"# Bug report\n\n### Bug description:\n\nThe AST unparsing of `Interpolation` objects does not reproduce formatting within interpolations.\n\nThis is true both for `ast.unparse` in Python:\n\n```\n\u003e\u003e\u003e ast.unparse(ast.parse('t\"{a   + b}\"'))\n\"t'{a + b}'\"\n```\n\nAnd for the C unparse that is used by `from __future__ import annotations`:\n\n```\n\u003e\u003e\u003e ns = {}\n\u003e\u003e\u003e exec(\"\"\"\n... from __future__ import annotations\n... def f(x: t\"{a    + b}\"): ...\n... \"\"\", ns)\n\u003e\u003e\u003e ns[\"f\"].__annotations__\n{'x': \"t'{a + b}'\"}\n```\n\nIn general, we can't recover the original source exactly, but in this case we do have the original source available:\n\n```\n\u003e\u003e\u003e ast.parse('t\"{a   + b}\"').body[0].value.values[0].str\n'a   + b'\n```\n\nLet's use it.\n\n### CPython versions tested on:\n\n3.14\n\n### Operating systems tested on:\n\n_No response_\n\n\u003c!-- gh-linked-prs --\u003e\n### Linked PRs\n* gh-133635\n* gh-133666\n* gh-133724\n* gh-133731\n\u003c!-- /gh-linked-prs --\u003e\n","author":{"url":"https://github.com/JelleZijlstra","@type":"Person","name":"JelleZijlstra"},"datePublished":"2025-05-07T14:40:59.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":7},"url":"https://github.com/133581/cpython/issues/133581"}