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Fix type signature for callables passed to Converter with takes_self=True #1382

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Fix type signature for callables passed to Converter with takes_self=True #1382

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7 changes: 5 additions & 2 deletions src/attr/__init__.pyi
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Original file line number Diff line number Diff line change
Expand Up @@ -95,13 +95,16 @@ def Factory(
In = TypeVar("In")
Out = TypeVar("Out")

# Callable might type check against the specific attrs-defined class.
_AttrsInstance = TypeVar("_AttrsInstance", bound=AttrsInstance)

class Converter(Generic[In, Out]):
@overload
def __init__(self, converter: Callable[[In], Out]) -> None: ...
@overload
def __init__(
self,
converter: Callable[[In, AttrsInstance, Attribute], Out],
converter: Callable[[In, _AttrsInstance, Attribute], Out],
*,
takes_self: Literal[True],
takes_field: Literal[True],
Expand All @@ -116,7 +119,7 @@ class Converter(Generic[In, Out]):
@overload
def __init__(
self,
converter: Callable[[In, AttrsInstance], Out],
converter: Callable[[In, _AttrsInstance], Out],
*,
takes_self: Literal[True],
) -> None: ...
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16 changes: 8 additions & 8 deletions tests/test_mypy.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -911,28 +911,28 @@
main:22: error: No overload variant of "Converter" matches argument types "Callable[[Any], str]", "bool" [call-overload]
main:22: note: Possible overload variants:
main:22: note: def [In, Out] Converter(self, converter: Callable[[In], Out]) -> Converter[In, Out]
main:22: note: def [In, Out] Converter(self, converter: Callable[[In, AttrsInstance, Attribute[Any]], Out], *, takes_self: Literal[True], takes_field: Literal[True]) -> Converter[In, Out]
main:22: note: def [In, Out, _AttrsInstance: AttrsInstance] Converter(self, converter: Callable[[In, _AttrsInstance, Attribute[Any]], Out], *, takes_self: Literal[True], takes_field: Literal[True]) -> Converter[In, Out]
main:22: note: def [In, Out] Converter(self, converter: Callable[[In, Attribute[Any]], Out], *, takes_field: Literal[True]) -> Converter[In, Out]
main:22: note: def [In, Out] Converter(self, converter: Callable[[In, AttrsInstance], Out], *, takes_self: Literal[True]) -> Converter[In, Out]
main:22: note: def [In, Out, _AttrsInstance: AttrsInstance] Converter(self, converter: Callable[[In, _AttrsInstance], Out], *, takes_self: Literal[True]) -> Converter[In, Out]
main:23: error: No overload variant of "Converter" matches argument types "Callable[[Any, Attribute[Any]], str]", "bool" [call-overload]
main:23: note: Possible overload variants:
main:23: note: def [In, Out] Converter(self, converter: Callable[[In], Out]) -> Converter[In, Out]
main:23: note: def [In, Out] Converter(self, converter: Callable[[In, AttrsInstance, Attribute[Any]], Out], *, takes_self: Literal[True], takes_field: Literal[True]) -> Converter[In, Out]
main:23: note: def [In, Out, _AttrsInstance: AttrsInstance] Converter(self, converter: Callable[[In, _AttrsInstance, Attribute[Any]], Out], *, takes_self: Literal[True], takes_field: Literal[True]) -> Converter[In, Out]
main:23: note: def [In, Out] Converter(self, converter: Callable[[In, Attribute[Any]], Out], *, takes_field: Literal[True]) -> Converter[In, Out]
main:23: note: def [In, Out] Converter(self, converter: Callable[[In, AttrsInstance], Out], *, takes_self: Literal[True]) -> Converter[In, Out]
main:23: note: def [In, Out, _AttrsInstance: AttrsInstance] Converter(self, converter: Callable[[In, _AttrsInstance], Out], *, takes_self: Literal[True]) -> Converter[In, Out]
main:25: note: Revealed type is "attr.Converter[Any, builtins.str]"
main:26: error: No overload variant of "Converter" matches argument types "Callable[[Any], str]", "bool" [call-overload]
main:26: note: Possible overload variants:
main:26: note: def [In, Out] Converter(self, converter: Callable[[In], Out]) -> Converter[In, Out]
main:26: note: def [In, Out] Converter(self, converter: Callable[[In, AttrsInstance, Attribute[Any]], Out], *, takes_self: Literal[True], takes_field: Literal[True]) -> Converter[In, Out]
main:26: note: def [In, Out, _AttrsInstance: AttrsInstance] Converter(self, converter: Callable[[In, _AttrsInstance, Attribute[Any]], Out], *, takes_self: Literal[True], takes_field: Literal[True]) -> Converter[In, Out]
main:26: note: def [In, Out] Converter(self, converter: Callable[[In, Attribute[Any]], Out], *, takes_field: Literal[True]) -> Converter[In, Out]
main:26: note: def [In, Out] Converter(self, converter: Callable[[In, AttrsInstance], Out], *, takes_self: Literal[True]) -> Converter[In, Out]
main:26: note: def [In, Out, _AttrsInstance: AttrsInstance] Converter(self, converter: Callable[[In, _AttrsInstance], Out], *, takes_self: Literal[True]) -> Converter[In, Out]
main:27: error: No overload variant of "Converter" matches argument types "Callable[[Any, AttrsInstance], str]", "bool" [call-overload]
main:27: note: Possible overload variants:
main:27: note: def [In, Out] Converter(self, converter: Callable[[In], Out]) -> Converter[In, Out]
main:27: note: def [In, Out] Converter(self, converter: Callable[[In, AttrsInstance, Attribute[Any]], Out], *, takes_self: Literal[True], takes_field: Literal[True]) -> Converter[In, Out]
main:27: note: def [In, Out, _AttrsInstance: AttrsInstance] Converter(self, converter: Callable[[In, _AttrsInstance, Attribute[Any]], Out], *, takes_self: Literal[True], takes_field: Literal[True]) -> Converter[In, Out]
main:27: note: def [In, Out] Converter(self, converter: Callable[[In, Attribute[Any]], Out], *, takes_field: Literal[True]) -> Converter[In, Out]
main:27: note: def [In, Out] Converter(self, converter: Callable[[In, AttrsInstance], Out], *, takes_self: Literal[True]) -> Converter[In, Out]
main:27: note: def [In, Out, _AttrsInstance: AttrsInstance] Converter(self, converter: Callable[[In, _AttrsInstance], Out], *, takes_self: Literal[True]) -> Converter[In, Out]

- case: testAttrsCmpWithSubclasses
regex: true
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40 changes: 40 additions & 0 deletions tests/typing_example.py
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Original file line number Diff line number Diff line change
Expand Up @@ -181,6 +181,46 @@ class ConvCToBool:
ConvCToBool("n")


# Converter instances with takes_self=True and/or takes_field=True
def str2int_self(s: str | int, self_: "CCC") -> int:
return int(s)


def str2int_field(s: str | int, field_: attrs.Attribute) -> int:
return int(s)


def str2int_both(s: str | int, self_: "CCC", field_: attrs.Attribute) -> int:
return int(s)


# XXX: Fails with E: Unsupported converter, only named functions, types and lambdas are currently supported [misc]
# See https://github.com/python/mypy/issues/15736
#
# So let's suppress the [misc] category, which still tests the [call-override] matching the callables.
@attrs.define
class CCC:
x: int = attrs.field(
converter=attrs.Converter( # type: ignore[misc]
str2int_self,
takes_self=True,
)
)
y: int = attrs.field(
converter=attrs.Converter( # type: ignore[misc]
str2int_field,
takes_field=True,
)
)
z: int = attrs.field(
converter=attrs.Converter( # type: ignore[misc]
str2int_both,
takes_self=True,
takes_field=True,
)
)


# Validators
@attr.s
class Validated:
Expand Down