gh-137226: Fix behavior of ForwardRef.evaluate with type_params by JelleZijlstra · Pull Request #137227 · python/cpython

@JelleZijlstra

The previous behavior was copied from earlier typing code. It works around the way
typing.get_type_hints passes its namespaces, but I don't think the behavior is logical
or correct.

Yhg1s

miss-islington pushed a commit to miss-islington/cpython that referenced this pull request

Aug 13, 2025
…pythonGH-137227)

The previous behavior was copied from earlier typing code. It works around the way
typing.get_type_hints passes its namespaces, but I don't think the behavior is logical
or correct.
(cherry picked from commit 089a324)

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>

hugovk pushed a commit that referenced this pull request

Aug 13, 2025

JelleZijlstra added a commit to JelleZijlstra/typing_extensions that referenced this pull request

Aug 16, 2025

Agent-Hellboy pushed a commit to Agent-Hellboy/cpython that referenced this pull request

Aug 19, 2025
…python#137227)

The previous behavior was copied from earlier typing code. It works around the way
typing.get_type_hints passes its namespaces, but I don't think the behavior is logical
or correct.

kumaraditya303 pushed a commit to miss-islington/cpython that referenced this pull request

Sep 9, 2025

JelleZijlstra added a commit to JelleZijlstra/cpython that referenced this pull request

Sep 15, 2025
…gified annotations

This issue appears specifically for TypedDicts because the TypedDict constructor
code converts string annotations to ForwardRef objects, and those are not evaluated
properly by the get_type_hints() stack because of other shenanigans with type
parameters.

This issue does not affect normal generic classes because their annotations are not
pre-converted to ForwardRefs.

The fix attempts to restore the pre- python#137227 behavior in the narrow scenario where
the issue manifests. It mostly makes changes only in the paths accessible from get_type_hints(),
ensuring that newer APIs (such as evaluate_forward_ref() and annotationlib) are not affected
by get_type_hints()'s past odd choices. This PR does not fix python#138949, an older issue I
discovered while playing around with this one; we'll need a separate and perhaps more
invasive fix for that, but it should wait until after 3.14.0.

JelleZijlstra added a commit that referenced this pull request

Sep 16, 2025
… annotations (#138953)

This issue appears specifically for TypedDicts because the TypedDict constructor
code converts string annotations to ForwardRef objects, and those are not evaluated
properly by the get_type_hints() stack because of other shenanigans with type
parameters.

This issue does not affect normal generic classes because their annotations are not
pre-converted to ForwardRefs.

The fix attempts to restore the pre- #137227 behavior in the narrow scenario where
the issue manifests. It mostly makes changes only in the paths accessible from get_type_hints(),
ensuring that newer APIs (such as evaluate_forward_ref() and annotationlib) are not affected
by get_type_hints()'s past odd choices. This PR does not fix issue #138949, an older issue I
discovered while playing around with this one; we'll need a separate and perhaps more
invasive fix for that, but it should wait until after 3.14.0.

JelleZijlstra added a commit to JelleZijlstra/cpython that referenced this pull request

Sep 16, 2025
…h stringified annotations (pythonGH-138953)

This issue appears specifically for TypedDicts because the TypedDict constructor
code converts string annotations to ForwardRef objects, and those are not evaluated
properly by the get_type_hints() stack because of other shenanigans with type
parameters.

This issue does not affect normal generic classes because their annotations are not
pre-converted to ForwardRefs.

The fix attempts to restore the pre- pythonGH-137227 behavior in the narrow scenario where
the issue manifests. It mostly makes changes only in the paths accessible from get_type_hints(),
ensuring that newer APIs (such as evaluate_forward_ref() and annotationlib) are not affected
by get_type_hints()'s past odd choices. This PR does not fix issue pythonGH-138949, an older issue I
discovered while playing around with this one; we'll need a separate and perhaps more
invasive fix for that, but it should wait until after 3.14.0.
(cherry picked from commit 6d6aba2)

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>