astral-sh/ty 0.0.1-alpha.22

on GitHub

Release Notes

Released on 2025-10-10.

Bug fixes

• Enforce that typing_extensions must come from a stdlib search path. This fixes a panic that could occur with a confusing backtrace if the extra-paths setting was incorrectly used to point to a virtual environment (#20715)
• Fix server panic when opening a project located at / in the file system (#20684)
• Fix panics when using --output-format=gitlab in CI environments (#20550)
• Fix stack overflows that could occur when attempting to determine if a recursive NamedTuple type was disjoint from another type (#20538)
• Fix panics in type inference when legacy TypeVars had bounds, constraints, or defaults that cyclically referred back to the TypeVar definition (directly or indirectly) (#20598)
• Fix situations where a panic during resolution of type-checker query cycles would manifest in a hang (#20577)
• When analyzing a .py file, do not error if there's also a .pyi for that module (#20461)
• Recognise that the runtime object typing.Protocol is an instance of _ProtocolMeta (#20488)
• Fix logic that attempted to determine whether a user had explicitly activated a Conda environment, which has implications for the search paths ty uses for module resolution (#20675)
• Fix false negatives when iterables with the wrong type are unpacked into a function with a *args variadic parameter (#20511)

Support for Python 3.14

• Use 3.14 as the default version (#20725, #20759, #20760)
• Annotations are deferred by default for 3.14+ (#20799)
• Fix false positives when accessing __annotate__ (Py3.14+) or __warningregistry__ as a module global (#20154)

Improvements to TypeVar solving and inference of generic types

• Improve solving of a type variable T if it appears in a union with non-TypeVars (T | None, T | str | None, etc.) (#20749)
• More precise type inference for dictionary literals (#20523)
• When solving type variables, use type context to inform whether Literal types should be promoted to instance types (#20776)
• Use annotated parameters as type context when solving type variables (#20635)
• Correctly infer the return type of method calls when the method is annotated as returning Self (#20517, #20754)
• Use type context for inference of generic function calls (#20476)
• Use C[T] instead of C[Unknown] for the upper bound of Self (#20479)

Improvements to assignability, subtyping, and union simplification

• Fix overly strict assignability implementation for intersections with negated gradual elements (#20773)
• Ensure that C[Any] is understood as a subtype of C[object] if C is a covariant generic class (#20592)
• Ensure that ~T is never considered to be assignable to T where T is a type variable (#20606)
• Improve assignability/subtyping between two protocol types (#20368)
• Simplify Any | (Any & T) to Any (#20593)
• Optimise and generalise union/intersection simplification (#20602)
• Make protocol satisfiability checks more principled when a protocol has a method member that is generic over type variables scoped to the function (#20568)
• Fix subtyping of invariant generics specialized with Any, ensuring that (for example) list[Any] is not considered a subtype of list[Any] (#20650)

Server

• Add LSP debug information command (#20379)
• Add support for inlay hints on attribute assignment (#20485)

Improvements to diagnostics

• Improve diagnostics when a positional-only parameter is passed using a keyword argument (#20495)
• Improve disambiguations of class names in diagnostics (#20603, #20756)
• Improve diagnostics for bad @overload definitions (#20745)
• Truncate type display for long unions in some situations (#20730)
• Rename "possibly unbound" diagnostics to "possibly missing" (#20492)

Improvements to enum support

• Allow multiple aliases to point to the same member (#20669)
• implement auto() for StrEnum (#20524)

Improvements to ty's @overload implementation

• Support single-starred argument for overload call (#20223)
• Filter overloads using variadic parameters (#20547)

Other typing semantics and features

• Do not union the inferred type of a module-global symbol with Unknown for the symbol's type when accessed from external scopes (#20664)
• Ensure that class objects are understood as callable even if they do not override object.__new__ or object.__init__ (#20521)
• Add support for **kwargs (#20430)
• Ensure first-party module-resolution search paths always appear in a sensible order (#20629)
• Respect dataclass_transform parameters for metaclass-based models (#20780)
• Sync vendored typeshed stubs (#20658). Typeshed diff
• Bring ty's TypeIs narrowing behaviour closer to ty's narrowing behaviour for isinstance() checks. (#20591)
• dataclass_transform: Support frozen_default and kw_only_default (#20761)
• Allow any string Literal type expression as a key when constructing a TypedDict (#20792)
• Add --venv as an alias to --python on the command line (#20718)
• Add search paths listed in PYTHONPATH to search paths used for ty's module resolution (#20441, #20490)

Contributors

• @thejchap
• @mtshiba
• @Danielkonge
• @dcreager
• @MatthewMckee4
• @Gankra
• @BurntSushi
• @carljm
• @dhruvmanila
• @sharkdp
• @mmlb
• @fgiacome
• @Guillaume-Fgt
• @AlexWaygood
• @Renkai
• @InvalidPathException
• @ibraheemdev
• @fatelei
• @github-actions
• @MichaReiser
• @ntBre
• @danparizher

Install ty 0.0.1-alpha.22

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/astral-sh/ty/releases/download/0.0.1-alpha.22/ty-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://github.com/astral-sh/ty/releases/download/0.0.1-alpha.22/ty-installer.ps1 | iex"

Download ty 0.0.1-alpha.22