use class, use pyright: strict

Author: MarcoGorelli

pandas-stubs/_typing.pyi

@@ -576,8 +576,8 @@ S2 = TypeVar(
     | list[str],
 )
 
-UnknownSeries: TypeAlias = Series[Any]
-UnknownIndex: TypeAlias = Index[Any]
+class UnknownSeries(Series[Any]): ...
+class UnknownIndex(Index[Any]): ...
 
 IndexingInt: TypeAlias = (
     int | np.int_ | np.integer | np.unsignedinteger | np.signedinteger | np.int8

pandas-stubs/core/indexes/base.pyi

@@ -67,7 +67,7 @@ class Index(IndexOpsMixin[S1]):
     __hash__: ClassVar[None]  # type: ignore[assignment]
     # overloads with additional dtypes
     @overload
-    def __new__(  # pyright: ignore[reportOverlappingOverload]
+    def __new__(
         cls,
         data: Sequence[int | np.integer] | IndexOpsMixin[int] | np_ndarray_anyint,
         *,

pandas-stubs/core/series.pyi

@@ -249,7 +249,7 @@ class Series(IndexOpsMixin[S1], NDFrame):
         copy: bool = ...,
     ) -> Series[float]: ...
     @overload
-    def __new__(  # type: ignore[overload-overlap] # pyright: ignore[reportOverlappingOverload]
+    def __new__(  # type: ignore[overload-overlap]
         cls,
         data: Sequence[Never],
         index: Axes | None = ...,

pandas-stubs/core/strings.pyi

@@ -1,3 +1,4 @@
+# pyright: strict
 from collections.abc import (
     Callable,
     Sequence,
@@ -110,7 +111,7 @@ class StringMethods(NoNewAttributesMixin, Generic[T, _TS, _TM, _TS2]):
     def join(self, sep: str) -> T: ...
     def contains(
         self,
-        pat: str | re.Pattern,
+        pat: str | re.Pattern[str],
         case: bool = ...,
         flags: int = ...,
         na: Scalar | NaTType | None = ...,

tests/test_series.py

@@ -49,6 +49,7 @@
 from pandas._typing import (
     DtypeObj,
     Scalar,
+    UnknownSeries,
 )
 
 from tests import (
@@ -1594,7 +1595,7 @@ def test_string_accessors():
     check(assert_type(s3.str.extract(r"([ab])?(\d)"), pd.DataFrame), pd.DataFrame)
     check(assert_type(s3.str.extractall(r"([ab])?(\d)"), pd.DataFrame), pd.DataFrame)
     check(assert_type(s.str.find("p"), pd.Series), pd.Series)
-    check(assert_type(s.str.findall("pp"), pd.Series), pd.Series)
+    check(assert_type(s.str.findall("pp"), UnknownSeries), pd.Series)
     check(assert_type(s.str.fullmatch("apple"), "pd.Series[bool]"), pd.Series, np.bool_)
     check(assert_type(s.str.get(2), pd.Series), pd.Series)
     check(assert_type(s.str.get_dummies(), pd.DataFrame), pd.DataFrame)