Fix crash on Unpack used without arguments in class bases#21470
Merged
Conversation
analyze_unbound_tvar accessed t.args[0] unconditionally when the base was Unpack with no arguments (e.g. Protocol[Unpack]), raising IndexError. Return None in that case so a proper 'Free type variable expected' error is reported instead. Fixes python#21467
Contributor
|
According to mypy_primer, this change doesn't affect type check results on a corpus of open source code. ✅ |
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
2 participants
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
Fixes #21467.
analyze_unbound_tvaraccessedt.args[0]unconditionally when a class base wasUnpackwith no arguments (e.g.class C(Protocol[Unpack]): ...), raisingIndexError: tuple index out of rangeduring semantic analysis.This adds a guard returning
Nonein that case, so the existing "Free type variable expected in Protocol[...]" error is reported instead of crashing.Added a regression test in
check-typevar-tuple.test.