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[3.14] gh-133960: Improve typing.evaluate_forward_ref (GH-133961)#134663

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Merged

JelleZijlstra merged 1 commit intopython:3.14frommiss-islington:backport-57fef27-3.14

May 25, 2025

Merged

[3.14] gh-133960: Improve typing.evaluate_forward_ref (GH-133961)#134663

JelleZijlstra merged 1 commit intopython:3.14frommiss-islington:backport-57fef27-3.14

May 25, 2025

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miss-islington commentedMay 25, 2025•
edited by github-actionsbot
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As explained inGH-133960, this removes most of the behavior differences with ForwardRef.evaluate.
The remaining difference is about recursive evaluation of forwardrefs; this is practically useful
in cases where an annotation refers to a type alias that itself is string-valued.

This also improves several edge cases that were previously not handled optimally. For example,
the function now takes advantage of the partial evaluation behavior of ForwardRef.evaluate() to
evaluate more ForwardRefs in the FORWARDREF format.

This alsofixesGH-133959 as a side effect, because the buggy behavior inGH-133959 derives from
evaluate_forward_ref().
(cherry picked from commit57fef27)

Co-authored-by: Jelle Zijlstrajelle.zijlstra@gmail.com

📚 Documentation preview 📚:https://cpython-previews--134663.org.readthedocs.build/

pythongh-133960: Improve typing.evaluate_forward_ref (pythonGH-133961)

f64c059

As explained inpythonGH-133960, this removes most of the behavior differences with ForwardRef.evaluate.The remaining difference is about recursive evaluation of forwardrefs; this is practically usefulin cases where an annotation refers to a type alias that itself is string-valued.This also improves several edge cases that were previously not handled optimally. For example,the function now takes advantage of the partial evaluation behavior of ForwardRef.evaluate() toevaluate more ForwardRefs in the FORWARDREF format.This alsofixespythonGH-133959 as a side effect, because the buggy behavior inpythonGH-133959 derives fromevaluate_forward_ref().(cherry picked from commit57fef27)Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>