[3.14] gh-137226: Fix get_type_hints() on generic TypedDict with stringified annotations (GH-138953) - #138989
Merged
hugovk merged 1 commit intoSep 17, 2025
Merged
Conversation
Copy link
Copy Markdown
Member
Sorry, something went wrong.
…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>
This was referenced Sep 16, 2025
AlexWaygood
approved these changes
Sep 16, 2025
Closed
5 tasks
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
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- GH-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 GH-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)