ruff/crates/ty_python_semantic/resources
David Peter d4eb4277ad
[ty] Add basic support for dataclasses.field (#19553)
## Summary

Add basic support for `dataclasses.field`:
* remove fields with `init=False` from the signature of the synthesized
`__init__` method
* infer correct default value types from `default` or `default_factory`
arguments

```py
from dataclasses import dataclass, field

def default_roles() -> list[str]:
    return ["user"]

@dataclass
class Member:
    name: str
    roles: list[str] = field(default_factory=default_roles)
    tag: str | None = field(default=None, init=False)

# revealed: (self: Member, name: str, roles: list[str] = list[str]) -> None
reveal_type(Member.__init__)
```

Support for `kw_only` has **not** been added.

part of https://github.com/astral-sh/ty/issues/111

## Test Plan

New Markdown tests
2025-07-25 14:56:04 +02:00
..
corpus [ty] Do not consider a type T to satisfy a method member on a protocol unless the method is available on the meta-type of T (#19187) 2025-07-25 11:16:04 +01:00
mdtest [ty] Add basic support for dataclasses.field (#19553) 2025-07-25 14:56:04 +02:00
primer [ty] Upgrade mypy_primer (#19207) 2025-07-08 15:56:54 +01:00
README.md Rename Red Knot (#17820) 2025-05-03 19:49:15 +02:00

Markdown files within the mdtest/ subdirectory are tests of type inference and type checking; executed by the tests/mdtest.rs integration test.

See crates/ty_test/README.md for documentation of this test format.