Published 1.1.333

Bug Fix: Fixed a bug that resulted in a false negative when assigning one TypedDict to another TypedDict. Field types should be treated as invariant rather than covariant because they are mutable (unless marked readonly).

Enhancement: Improved the synthesized update method for TypedDict classes so it supports keyword arguments and iterables of tuples.

Bug Fix: Improved error message for protocol mismatch when a method in the source cannot be bound.

Performance: Added performance improvement that speeds up type checking for TypedDict classes that have a large number of entries.

Bug Fix: Fixed a bug that led to a false positive when doing protocol matching for a protocol that uses deeply nested recursion.

Bug Fix: Fixed a bug that resulted in incorrect narrowing on assignment when the assigned type is a tuple that includes one or more Any type arguments and the declared type is a tuple without an Any.

Bug Fix: Fixed a bug that led to a false positive error when doing protocol matching for a protocol and implementation that use a combination of class-scoped and function-scoped TypeVars.

Bug Fix: Fixed several bugs in ReadOnly TypedDict functionality based on the latest draft of the PEP 705.

Enhancement: Extended the len(x) == L type guard logic to support arbitrary expressions L that evaluate to a literal int type.

Behavior Change: Removed support for readonly keyword parameter for TypedDict to reflect latest changes in PEP 705.

Bug Fix: Fixed bug in protocol matching when source is a namedtuple or a frozen dataclass. Algorithm wasn't taking into account that attributes in these classes are immutable.

Published 1.1.332

Bug Fix: Fixed crash that occurs when encountering a malformed system version check of the form sys.version_info[0] < 3.8.

Enhancement: Improved error message for yield statements when the yield type is a TypedDict or other type that requires bidirectional type inference.

Bug Fix: Fixed regression in type(x) is y type narrowing logic when y is of type type[Self].

Bug Fix: Fixed a bug in protocol matching logic that resulted in a false positive error when a class implementation used a callback protocol rather than a def statement to define an instance variable defined in a protocol.

Bug Fix: Fixed a bug that resulted in an unresolved Unknown type within a tuple constructed within a loop.

Bug Fix: Fixed several bugs in protocol matching that led to false positives when matching a protocol against a module.

Behavior Change: Changed type evaluation behavior for accesses to attributes on a class that derives from Any. Previously, these were evaluated as Unknown, but they are now evaluated as Any.

Bug Fix: Fixed a bug in the reportIncompatibleMethodOverride check that leads to a false negative if the base class uses a Self type and the override uses an incompatible specialized type.

Enhancement: Added logic to detect illegal use of the symbol Any.

Enhancement: Added logic to perform basic reformatting (especially dedenting) of deprecation messages used with @deprecated.

Bug Fix: Fixed a bug in the isinstance type guard logic when the specified filter class (the second argument) is a metaclass (a subclass of type).

Bug Fix: Fixed a bug in the issubclass type narrowing logic when the first argument is a metaclass (a subclass of type).

Enhancement: Updated typeshed stubs to the latest version.

Behavior Change: Changed override-related checks (reportIncompatibleMethodOverride, reportIncompatibleVariableOverride and reportImplicitOverride) so they apply to stub files. Previously, these were skipped for stubs.

Bug Fix: Fixed a bug that caused types captured by ParamSpecs to sometimes be printed with Unknown parameter types.

Bug Fix: Fixed a bug in ParamSpec type matching that resulted in an incorrect type evaluation under certain circumstances.

Bug Fix: Fixed a regression in overload matching that resulted in false positive errors in hydra-zen. This change involves removing a heuristic from overload matching that attempted to eliminate a false positive error for x: list[str] = "a,b".split(",").

Bug Fix: Fixed a bug that results in confusing error messages when converting a constructor (an __init__ method) to a function type. The resulting function should not be named __init__ but should be anonymous.

Bug Fix: Fixed a bug that led to a false positive error when a type alias created using PEP 695 syntax is used as a type argument for a generic type when used in the LHS of a call expression.

Bug Fix: Fixed a bug in the isinstance type narrowing logic when using a generic class whose type parameters include defaults (PEP 696).

Bug Fix: Fixed a false positive error "TypeVar bound cannot be generic" if the bound type is a generic class whose type parameters have default types (using PEP 696).

Bug Fix: Fixed bug in "type printer", the code that converts a type to text for error messages. It wasn't properly handling type(t) where t is defined using a type alias.

Enhancement: Improved the error message for metaclass conflicts so the conflicting metaclasses are specified.

Bug Fix: Fixed a bug in the type narrowing logic for sequence patterns, specifically when the subject is Any or Unknown and the sequence pattern is empty ([]).

Bug Fix: Fixed a bug with path normalization (in particular, drive letter) for symbolic links that resulted in false positive errors.

Bug Fix: Fixed a bug that led to a false positive error when attempting to instantiate a value of type type[Self] when Self refers to an abstract class.

Bug Fix: Fixed a bug that led to a false positive error when passing type(None) or NoneType as the second argument to issubclass.

Bug Fix: Fixed a bug in the issubclass type narrowing logic for type(None) and NoneType filters.

Bug Fix: Fixed a bug that led to a stack overflow crash under certain circumstances when evaluating a function call with a ParamSpec.

Bug Fix: Fixed bug that prevented ReadOnly experimental feature from being used in a file where a # pyright: enableExperimentalFeatures=True comment was used.

Published 1.1.331

Bug Fix: Fixed a bug that led to a false positive error and incorrect type evaluation under certain circumstances when multiple symbols depend on each other in a loop.

Bug Fix: Fixed a recent regression that led to a false positive error when a class uses a custom metaclass that supplies a __setattr__ method.

Enhancement: Improved type narrowing in the negative case for isinstance when the filter type (the second argument) is type[T] (where T is a type variable) and the first argument is of type T. In this case, we can eliminate (filter) T in the negative case.

Bug Fix: Fixed a bug that led to a false positive error when using a zero-argument super() call within a class declaration within a method body.

Enhancement: Added support for @deprecated when applied to property accessors and descriptor methods.

Bug Fix: Fixed a bug that led to a false positive error when doing protocol matching with a protocol class that has a method with method-scoped type variables.

Enhancement: Added missing check for the use of a subscripted Callable within an isinstance call.

Bug Fix: Fixed bug that led to incorrect type narrowing for isinstance when using Callable and the pre-narrowed type is object.

Bug Fix: Fixed a bug that led to incorrect type evaluation in a nested set of call expressions and a lambda.

Bug Fix: Fixed a bug that led to a confusing error message when assigning a value with an incompatible type to a class variable that has no explicit type declaration.

Bug Fix: Fixed bug in x is <Literal> and x == <Literal> type guard logic. It was not properly handling the case where x is Any or Unknown.

Bug Fix: Fixed a bug that led to incorrect type narrowing in the type(x) is T and type(x) == T type guards when T is a dynamic type rather than a specific class.

Enhancement: Improved completion provider logic for __getitem__ methods with literal types. The old logic didn't properly handle generics or overloads.

Enhancement: Don't show stubPath xxx is not a valid directory warning in logs when using config default.

Published 1.1.330

Bug Fix: Fixed a bug in the diagnostic filtering logic that caused the grayed-out "unused symbol" treatment to be suppressed when using a # pyright: ignore comment. This comment is intended to apply only to real diagnostics (errors, warnings, infos), not hints with tags.

Bug Fix: Fixed a bug that resulted in incorrect type evaluation when accessing an attribute on a class whose metaclass defines a __getattr__ method and the target attribute is a descriptor object.

Bug Fix: Fixed a crash that can occur if a type annotation includes too many type arguments for a class.

Bug Fix: Fixed a regression that resulted in a false positive error when using float or complex literals or constructor calls and then accessing a member of the resulting object that is valid on that class but not on int.

Bug Fix: Fixed a recent regression in the overload matching behavior that broke two tests in the pandas-stubs test suite.

Bug Fix: Fixed a bug that resulted in a false positive in certain circumstances where a lambda included simple math operations with integer literals. The fix requires disabling literal math within lambdas, since they are often used as callbacks that are called repeatedly in a loop.

Bug Fix: Reverted a portion of the recent changes designed to differentiate between a float that is really a float or a float that can also be an int. This resulted in false positives when inferring types using float literals.

Bug Fix: Fixed a false positive due to incorrect type narrowing logic when a del statement targets a specific element within a list (e.g. del my_list[1]).

Bug Fix: Fixed a crash due to an invalid assert that occurs when a class or function that uses PEP 695 syntax is unreachable.

Bug Fix: Fixed a bug that led to incorrect type evaluation and false positives when constructing a specialized generic TypedDict.

Enhancement: Updated typeshed stubs to the latest version.

Enhancement: Improved the check for whether an object is "awaitable". Rather than hard-coding checks for __await__ and __init__ methods, use the typing.Awaitable protocol.

Bug Fix: Fixed a false positive reportInvalidStringEscapeSequence error if a string literal is over 32K in length and the 32768'th character is a backslash.

Enhancement: Added support for PEP 692 (unpacked TypedDict for **kwargs) when used with a ParamSpec.

Bug Fix: Fixed a bug that led to the loss of type narrowing for a captured variable used within an inner scope if used in a comprehension expression.

Behavior Change: Changed the default Python version (the version that is assumed by pyright if it has no other context) from 3.11 to 3.12 now that 3.12 is final.

Enhancement: Improved diagnostic for the situation where overload matching fails to find any applicable overloads.

Bug Fix: Fixed a bug that resulted in incorrect type evaluation when an async function with an inferred return type is decorated with a class or function that uses a ParamSpec (such as functools.wraps).

Bug Fix: Fixed a bug that led to a false positive error when using a single-quote form of a format string that uses a format specifier expression. This is also a bug in the Python 3.12 interpreter that is being fixed.

Published 1.1.329

Behavior Change: Added new configuration switch disableBytesTypePromotions that is off by default except in strict mode, when it's on by default. When enabled, it eliminates the old (poorly-documented) behavior whereby bytes when used in a type annotation automatically implies the union bytes | bytearray | memoryview. For details, refer to PEP 688. The configuration switch allows code bases to retain the old behavior, but it's likely that the default value of this option will change to true in the future.

Behavior Change: Improved handling of types float and complex, which are special-cased in PEP 484 as "promotion types". The new logic now properly models the runtime behavior for isinstance and class pattern matching when used with these promotion types.

Behavior Change: Added check for the use of an ellipsis for a default argument value for a function that is not in a stub, not overloaded, and without a placeholder implementation.

Bug Fix: Fixed false positive error that occurs when a member of a frozen dataclass is overridden in a subclass. In this case, the type should not be considered invariant because the field isn't mutable.

Bug Fix (from pylance): Fixed recent regression that caused import resolution issues when using UNC paths and symlinks.

Bug Fix: Fixed several issues with logic that performs protocol matching against a module, including a false positive error when matching against a generic protocol.

Bug Fix: Fixed bug in type compatibility checks for LiteralString. It should not be considered compatible with str or a specific literal str in an invariant context.

Bug Fix: Fixed a false positive error with the reportUnnecessaryComparison check when a recursive type alias is used.

Bug Fix: Fixed a bug in the handling of __match_args__ in class pattern matching. Pyright was using the subject's class rather than the pattern's class to look up __match_args__.

Bug Fix: Fixed a bug in the handling of class pattern matching for subclasses of int, str or other stdlib classes that implicitly supply __match_args__ and return self for matches.

Enhancement: Added a check for class pattern matches where the number of positional patterns exceeds the number of positional fields supported by the class.

Enhancement: Improved error message for type compatibility for list and dict types, which enforce invariance. The new error message now suggest the use of Sequence and Mapping, respectively.

Published 1.1.328

Behavior Change: Added code to enforce invariance of class-scoped variables in overrides when the reportIncompatibleVariableOverride rule is enabled.

Bug Fix: Fixed bug that results in import resolution errors when symlinks are used.

Bug Fix: Fixed a bug that caused a typing.deprecated decorator not to be marked as such.

Bug Fix: Fixed a bug that resulted in a false positive error when *args and **kwargs are passed as arguments to a function with a ParamSpec and the types of *args and **kwargs is Any.

Bug Fix: Fixed bug that caused @deprecated message not to be passed through a ParamSpec.

Bug Fix: Fixed a bug that results in incorrect type narrowing for a mapping pattern if the subject type is a superclass of Mapping, such as object.

Bug Fix: Fixed inconsistent behavior of @deprecated between overloaded and non-overloaded functions.

Bug Fix: Improved validation of generator return type. Previously, the check was performed only for yield statements, but it's possible to define a generator function that has no reachable yield statements.

Bug Fix: Fixed bug that led to a false positive error when checking for out-of-bounds tuple accesses if the indexed type is a union that includes both a bounded tuple and an unbounded tuple.

Behavior Change: Updated the synthesized pop method for TypedDict so its signature is consistent with the synthesized get method. This eliminates an Unknown in some cases.

Bug Fix: Fixed bug that led to incorrect generation of Unknown type evaluation when an overloaded function is called in a loop and one of the arguments to the call depends on the return value.

Enhancement: Updated typeshed stubs to the latest version.

Bug Fix: Fixed a regression that caused an Unknown to appear in a type evaluation when using nested constructor calls.

Published 1.1.327

Bug Fix: Fixed a bug in the isinstance type narrowing logic that evaluated the incorrect type when two protocol classes are involved.

Bug Fix: Fixed a bug that led to a false positive error when enclosing ... in quotes when specifying a ParamSpec default value.

Bug Fix: Fixed bug that resulted in false positive error when using a Union[*Ts] value in a binary expression.

Bug Fix: Fixed a recent regression that caused the pythonPath received from the client to be corrupted resulting in import resolution errors.

Behavior Change: Updated class specialization logic to conform to latest draft of PEP 696 when a class type parameter has a default type and that class is bound to one of its methods.

Enhancement: Improved error message for type argument mismatch when in an invariant context.

Behavior Change: Changed behavior to allow a class variable within a protocol to be marked Final without assigning a value to it in the protocol definition.

Bug Fix: Fixed a bug that results in a spurious error under certain circumstances when evaluating the type of a parameter within a nested function whose type refers to an outer-scope type variable.

Enhancement: Added check for a conditional expression that evaluates to a coroutine, which always evaluates to True. This is likely indicative of a missing await keyword.

Enhancement: Improved the type narrowing logic for the len(x) == L type narrowing pattern for tuples. The new logic supports narrowing of tuples with an indeterminate length (a ... entry).

Behavior Change: Removed check for empty body of @overload function.

Bug Fix: Fixed a false positive error when a TypeVar with a default value (as specified in PEP 696) appears within a method after an outer-scoped TypeVar without a default value.

Bug Fix: Fixed a bug that led to a false positive error when a frozen dataclass has an explicit __eq__ method and is used in way that requires it to be Hashable.

Bug Fix: Improved error messages that include module names. Previously, there were inconsistencies in how module names were reported.

Bug Fix: Fixed false positive error when using a forward-declared reference inside of an inlined TypedDict when from __future__ import annotations is in effect.

Bug Fix: Fixed a bug that led to a false negative when using a non-TypedDict base class within a TypedDict class statement.

Published 1.1.326

Bug Fix: Fixed a bug in the recently-introduced deprecateTypingAliases feature that resulted in false positives when Counter, OrderedDict and ChainMap were imported from collections.

Bug Fix: Fixed a bug that led to a false positive when an enum literal annotation is used within the enum class definition and from __future__ import annotations is in use.

Bug Fix: Added code to mark symbols as accessed if they're imported directly into a class scope using a from x import y statement.

Bug Fix: Fixed a bug that resulted in a false positive error when assigning an unpacked TypeVarTuple to an unpacked tuple[Any, ...] in an invariant context.

Bug Fix: Fixed bug that results in a false positive error during protocol matching when a NamedTuple is matched against a protocol using _fields or other attributes defined in the NamedTuple class.

Bug Fix: Fixed bug that led to a false positive error when determining whether the target of an awaited call is a NoReturn.

Behavior Change: Changed the default of useLibraryCodeForTypes from false to true in the LSP settings. (It was changed to true in all other places previously, but this case was missed.)

Bug Fix: Fixed a bug that led to an incorrect type evaluation in certain cases where a type argument for a function call argument type is left unspecified (and is therefore assumed to be Unknown).

Bug Fix: Fixed a bug that led to incorrect type narrowing for isinstance when the pre-narrowed type is a generic callable.

Bug Fix: Improved determinism of bidirectional type inference for dictionary, list, set and tuple expressions when the expected type is a union of types that includes more than one plausible candidate. The types in the union are now sorted so type evaluation doesn't depend on the order in which the union was defined.

Enhancement: Updated typeshed stubs to the latest version.

Bug Fix: Fixed bug that led to a false negative when @typing.deprecated is used on an async function.

Bug Fix: Fixed a bug that led to the incorrect type evaluation of a constructor call when bidirectional type inference is used and the expected type is a union that includes more than one compatible instance type.

Bug Fix: Fixed a deviation from the PEP 702 spec which indicates that when @deprecated is applied to an overloaded function implementation, that deprecation is meant to apply to all overloads.

Enhancement: Improved error message for deprecated methods.

Enhancement: Improved "no matching overloads" error message in cases where an argument is unpacked.

Enhancement: Added support for custom metaclasses that inject instance variables into the classes they construct.

Published 1.1.325

Bug Fix: Fixed a bug in the isinstance type guard logic that produced incorrect results when narrowing a generic class instance.

Bug Fix: Fixed a bug in the parser that led to a false positive syntax error when a match statement was followed by a - or ~ token.

Bug Fix: Improved logic that determines whether an object is callable. The __call__ attribute must be a class variable, not an instance variable.

Bug Fix: Improved isinstance and issubclass narrowing in the case where an intersection type is created and one of the two subclasses has a custom metaclass.

Behavior Change: Changed type evaluation behavior for a class variable that uses Self in its type definition. When accessed via a subclass (either through cls or self), the type is now assumed to be changed to Self of the child class. This makes pyright's behavior closer to mypy's in this case.

Bug Fix: Fixed regression that resulted in incorrect type evaluation and a spurious reportUnknownArgumentType error when calling the same constructor multiple times in a single call expression.

Bug Fix: Fixed a bug that caused a "py.typed" marker file to be ignored in a namespace package if the marker file is at the same directory level as the submodule being imported leading to a spurious reportMissingTypeStubs error.

Bug Fix: Fixed a bug that led to a false positive during overload matching when the arg type includes a union where one of the subtypes is a constrained TypeVar.

Enhancement: Added a new configuration option deprecateTypingAliases that enables deprecation detection and reporting for symbols imported from the typing module that are deprecated according to PEP 585 and 604. The option is currently disabled by default (even in strict mode) but can be enabled manually.

Behavior Change: Changed logic to exempt abstract overloaded methods within an ABC so an implementation is not required.

Bug Fix: Fixed check for illegal use of zero-argument super within an inner function located within a method.

Bug Fix: Fixed a bug that led to a false negative when a type annotation contains a stringified type on the LHS of an index expression.

Enhancement: Added support for @type_check_only decorator.

Enhancement: Improved error message for type incompatibility when type parameter is covariant or contravariant.

Enhancement: Updated typeshed stubs to the latest.

Bug Fix: Fixed a bug that led to incorrect type evaluation and false positive errors when a function with a ParamSpec was passed to another function with a ParamSpec.

Behavior Change: Changed interpretation of ... forms of tuples to improve consistency and match mypy's behavior. The type tuple[int, ...] is now interpreted as the union of all tuples of length zero or more that contain only int. Because this is a union, assigning a value of this type to a tuple type with a known (specified) length is now considered a type violation.

Bug Fix: Fixed several bugs in the logic for "strict type guard" positive and negative type narrowing.

Bug Fix: Fixed long-standing bug that caused various problems (including poor performance, incorrect type evaluations, and false negatives and false positives) when calling a constructor for a generic class within the class implementation.

Bug Fix: Fixed a bug that led to a false positive reportUnusedVariable error when a dynamic expression was used in a namedtuple call argument.

Bug Fix: Fixed a bug that led to a false positive reportIncompatibleMethodOverride error when a function-scoped type variable was used in a contravariant position.

Bug Fix: Fixed bug that led to the incorrect type evaluation when calling a generic function and a value of type P.args or P.kwargs is assigned to a type variable.

Bug Fix: Fixed a bug that led to a false negative error for an expression used within an f-string within a loop.

Published 1.1.324

Bug Fix: Fixed a bug that led to a false positive error under certain circumstances when a callable using Concatenate is assigned to another callable using Concatenate.

Bug Fix: Fixed bug that can result in a false positive error when a wildcard import targets a module that doesn't contain a __all__ definition but includes dundered names in its module namespace.

Bug Fix: Fixed a false positive error when invoking a call of a variable that is annotated using a PEP 695 type alias.

Bug Fix: Fixed a bug that caused an incorrect application of a ParamSpec in certain cases where the signature bound to the ParamSpec was generic.

Enhancement: Improved validation of NamedTuple and namedtuple factory calls.

Enhancement: Improved detection of redundant pattern capture targets in case statements.

Bug Fix: Changed the type evaluation logic for the enum value member so a custom value type can be specified in the Enum subclass.

Bug Fix: Fixed a bug that led to a false positive in the reportIncompatibleMethodOverride check in certain circumstances where the method in both the base class and child class are overloaded.

Bug Fix: Fixed bug that resulted in a false positive error when an async function with no return type annotation was called recursively.

Bug Fix: Fixed a bug that led to a false positive in the reportIncompatibleMethodOverride check when overriding a method with a ParamSpec.

Bug Fix: Fixed a recent regression that resulted in a false positive during protocol matching if the protocol defines an __eq__ method but doesn't include a __hash__ definition.

Bug Fix: Fixed bug that sometimes led to false positives or false negative in call expressions that involve keyword arguments followed by an unpacked.

Bug Fix: Fixed a bug that resulted in the incorrect textual form (used in error messages) for a generic class with a ParamSpec that is parameterized with ....

Bug Fix: Fixed regression that caused a spurious error with the reportIncompatibleMethodOverride check when a method with a ParamSpec was overridden by a method with *args: Any, **kwargs: Any.

Bug Fix: Fixed a bug that led to incorrect type narrowing on assignment in certain cases.

Enhancement: Added check for classes that have mutually-incompatible base classes due to generic type argument mismatches.

Bug Fix: Fixed bug that led to a false positive reportIncompatibleVariableOverride error when overriding a synthesized __hash__ symbol.

Bug Fix: Added heuristic to constraint solver logic to better handle the case where a parameter is annotated with a union of multiple "bare" TypeVars (like S | T). In this case, it's not clear whether the corresponding argument type should constrain S or T or both. We now defer the constraint during the first pass of arg/param type validation so additional references to S or T can help establish the appropriate constraint.

Bug Fix: Fixed a bug that led to incorrect type evaluation of Union[*Ts] (where Ts is a TypeVarTuple) in certain situations

Bug Fix: Fixed bug that resulted in incorrect type evaluation when passing a generic class as a Callable parameter more than once in the same call.

Enhancement: Added logic to mirror the (rather surprising) runtime behavior when an attribute is accessed from a class object and the metaclass defines an attribute of the same name that happens to be a descriptor object. The runtime favors the metaclass attribute in this case.

Enhancement: Extended inlined TypedDict prototype to support TypedDict as well as dict so we can compare the two proposals.

Bug Fix: Changed logic for handling the __get__ method of a descriptor so pyright more accurately models the runtime behavior when the descriptor is accessed through an object (as opposed to a class). Previously, pyright was modeling this as an Any value to avoid problems with type stubs that are not accurately modeling the runtime behavior, but this caused other unintended side effects.

Bug Fix (from Pylance): Fixed bug that led to internally-corrupted type state if the language server canceled a type evaluation request at just the wrong time.

Enhancement: Added logic to handle the case where a declared return type of a function includes a constrained TypeVar and a return statement is guarded by a case statement using a class pattern that guarantees that the constraint is met on that code path.