Improve type hinting of or_ (#1471)

* Improve type hinting of instance_of and or_

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Moved _U to same location as all other TypeVar definitions

Added a new TypeVar '_U' bound to UnionType for type validation.

* Revert to UnionType

* Add (failing) typing example

* Oops, the type checkers were just smarter

* Add news fragment

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Hynek Schlawack <[email protected]>

Author: 3 people

changelog.d/1474.change.md

@@ -0,0 +1,3 @@
+The type annotation for `attrs.validators.or_()` now allows for different types of validators.
+
+This was only an issue on Pyright.

src/attr/validators.pyi

@@ -20,6 +20,9 @@ _T = TypeVar("_T")
 _T1 = TypeVar("_T1")
 _T2 = TypeVar("_T2")
 _T3 = TypeVar("_T3")
+_T4 = TypeVar("_T4")
+_T5 = TypeVar("_T5")
+_T6 = TypeVar("_T6")
 _I = TypeVar("_I", bound=Iterable)
 _K = TypeVar("_K")
 _V = TypeVar("_V")
@@ -90,4 +93,48 @@ def not_(
     msg: str | None = None,
     exc_types: type[Exception] | Iterable[type[Exception]] = ...,
 ) -> _ValidatorType[_T]: ...
-def or_(*validators: _ValidatorType[_T]) -> _ValidatorType[_T]: ...
+@overload
+def or_(
+    __v1: _ValidatorType[_T1],
+    __v2: _ValidatorType[_T2],
+) -> _ValidatorType[_T1 | _T2]: ...
+@overload
+def or_(
+    __v1: _ValidatorType[_T1],
+    __v2: _ValidatorType[_T2],
+    __v3: _ValidatorType[_T3],
+) -> _ValidatorType[_T1 | _T2 | _T3]: ...
+@overload
+def or_(
+    __v1: _ValidatorType[_T1],
+    __v2: _ValidatorType[_T2],
+    __v3: _ValidatorType[_T3],
+    __v4: _ValidatorType[_T4],
+) -> _ValidatorType[_T1 | _T2 | _T3 | _T4]: ...
+@overload
+def or_(
+    __v1: _ValidatorType[_T1],
+    __v2: _ValidatorType[_T2],
+    __v3: _ValidatorType[_T3],
+    __v4: _ValidatorType[_T4],
+    __v5: _ValidatorType[_T5],
+) -> _ValidatorType[_T1 | _T2 | _T3 | _T4 | _T5]: ...
+@overload
+def or_(
+    __v1: _ValidatorType[_T1],
+    __v2: _ValidatorType[_T2],
+    __v3: _ValidatorType[_T3],
+    __v4: _ValidatorType[_T4],
+    __v5: _ValidatorType[_T5],
+    __v6: _ValidatorType[_T6],
+) -> _ValidatorType[_T1 | _T2 | _T3 | _T4 | _T5 | _T6]: ...
+@overload
+def or_(
+    __v1: _ValidatorType[Any],
+    __v2: _ValidatorType[Any],
+    __v3: _ValidatorType[Any],
+    __v4: _ValidatorType[Any],
+    __v5: _ValidatorType[Any],
+    __v6: _ValidatorType[Any],
+    *validators: _ValidatorType[Any],
+) -> _ValidatorType[Any]: ...

typing-examples/baseline_examples.py

@@ -93,6 +93,17 @@ class Validated:
     num: int = attrs.field(validator=attrs.validators.ge(0))
 
 
+@attrs.define
+class ValidatedInconsistentOr:
+    num: int | str = attrs.field(
+        validator=attrs.validators.or_(
+            # Various types of validators.
+            attrs.validators.ge(0),
+            attrs.validators.instance_of(str),
+        )
+    )
+
+
 attrs.validators.set_disabled(True)
 attrs.validators.set_disabled(False)