[3.15] gh-155525: Fix quadratic f-string tokenization (GH-156756) - #157828
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Adapt the original expression-span fix to the release tokenizer and retain interactive buffers while a formatted string is open. Co-authored-by: gwosti <322952417+gwosti@users.noreply.github.com>
…thonGH-156756) * pythongh-155525: Avoid quadratic f-string tokenization * fixup! pythongh-155525: Avoid quadratic f-string tokenization --------- (cherry picked from commit c1df6843d36233ec1da71a1d5f9b74dd6ebc9b97) Co-authored-by: gwosti <322952417+gwosti@users.noreply.github.com> Co-authored-by: Pablo Galindo Salgado <Pablogsal@gmail.com>
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The release tokenizer fix and interactive buffer retention are included. The final tree matches the debug build tested locally: 702 tests passed, including the CPU-resource cases and the new interactive regression.
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Backport gh-156756 to Python 3.15. Retain replacement expressions in the tokenizer buffer instead of repeatedly copying the remaining source. Preserve the expression pointers when the buffer grows, and keep the interactive buffer while a formatted string is open.
Main already received the implementation through gh-156484, so the automatic cherry-pick only brought over tests. This backport also adapts the original fix to the release tokenizer and adds coverage for multiline interactive expressions, which otherwise abort in a debug build.
The targeted parser and command-line tests pass in a debug build, including the CPU-resource tests.
(cherry picked from commit c1df684)
compile()/ast.parse()time for modules with many f-strings (PEP 701 tokenizerupdate_fstring_exprrescans the whole remaining buffer per replacement field) #155525