[ty] Synthesize read-only properties for all declared members on NamedTuple classes#19899
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AlexWaygood merged 3 commits intomainfrom Aug 14, 2025
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[ty] Synthesize read-only properties for all declared members on NamedTuple classes#19899AlexWaygood merged 3 commits intomainfrom
NamedTuple classes#19899AlexWaygood merged 3 commits intomainfrom
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Diagnostic diff on typing conformance testsChanges were detected when running ty on typing conformance tests--- old-output.txt 2025-08-14 21:23:47.772361962 +0000
+++ new-output.txt 2025-08-14 21:23:47.841362883 +0000
@@ -1,5 +1,5 @@
WARN ty is pre-release software and not ready for production use. Expect to encounter bugs, missing features, and fatal errors.
-fatal[panic] Panicked at /home/runner/.cargo/git/checkouts/salsa-e6f3bb7c2a062968/918d35d/src/function/execute.rs:215:25 when checking `/home/runner/work/ruff/ruff/typing/conformance/tests/aliases_typealiastype.py`: `infer_definition_types(Id(71d5)): execute: too many cycle iterations`
+fatal[panic] Panicked at /home/runner/.cargo/git/checkouts/salsa-e6f3bb7c2a062968/918d35d/src/function/execute.rs:215:25 when checking `/home/runner/work/ruff/ruff/typing/conformance/tests/aliases_typealiastype.py`: `infer_definition_types(Id(682a)): execute: too many cycle iterations`
_directives_deprecated_library.py:15:31: error[invalid-return-type] Function always implicitly returns `None`, which is not assignable to return type `int`
_directives_deprecated_library.py:30:26: error[invalid-return-type] Function always implicitly returns `None`, which is not assignable to return type `str`
_directives_deprecated_library.py:36:41: error[invalid-return-type] Function always implicitly returns `None`, which is not assignable to return type `Self@__add__`
@@ -676,6 +676,7 @@
namedtuples_type_compat.py:23:1: error[invalid-assignment] Object of type `Point` is not assignable to `tuple[int, str, str]`
namedtuples_usage.py:34:7: error[index-out-of-bounds] Index 3 is out of bounds for tuple `Point` with length 3
namedtuples_usage.py:35:7: error[index-out-of-bounds] Index -4 is out of bounds for tuple `Point` with length 3
+namedtuples_usage.py:40:1: error[invalid-assignment] Invalid assignment to data descriptor attribute `x` on type `Point` with custom `__set__` method
namedtuples_usage.py:41:1: error[invalid-assignment] Cannot assign to object of type `Point` with no `__setitem__` method
namedtuples_usage.py:52:1: error[invalid-assignment] Too many values to unpack: Expected 2
namedtuples_usage.py:53:1: error[invalid-assignment] Not enough values to unpack: Expected 4
@@ -859,5 +860,5 @@
typeddicts_operations.py:60:1: error[type-assertion-failure] Argument does not have asserted type `str | None`
typeddicts_type_consistency.py:101:1: error[invalid-assignment] Object of type `Unknown | None` is not assignable to `str`
typeddicts_usage.py:40:24: error[invalid-type-form] The special form `typing.TypedDict` is not allowed in type expressions. Did you mean to use a concrete TypedDict or `collections.abc.Mapping[str, object]` instead?
-Found 860 diagnostics
+Found 861 diagnostics
WARN A fatal error occurred while checking some files. Not all project files were analyzed. See the diagnostics list above for details. |
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AlexWaygood
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The new diagnostic in the typing conformance suite is correct -- this is a place where we previously had a false negative |
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There are some performance regressions of 1-2% on this PR due to the fact that we now need to eagerly check whether a class is an "exact |
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Only 1% regressions on Codspeed after rebasing on top of #19912. |
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Aug 14, 2025
* main: [ty] Add diagnostics for invalid `await` expressions (#19711) [ty] Synthesize read-only properties for all declared members on `NamedTuple` classes (#19899) [ty] Remove use of `ClassBase::try_from_type` from `super()` machinery (#19902) [ty] Speedup project file discovery (#19913) [`pyflakes`] Add secondary annotation showing previous definition (`F811`) (#19900) Bump 0.12.9 (#19917) [ty] support `kw_only=True` for `dataclass()` and `field()` (#19677)
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Summary
Currently we treat declared attributes on
NamedTupleclasses just like declared attributes on any other class. But this is not correct! At runtime, theNamedTuplemachinery synthesizes a read-only property for each attribute declared on aNamedTupleclass. This PR implements that behaviour.Test Plan
Mdtests