From 503b313c76e16a78f500e809dad40b5b895c0927 Mon Sep 17 00:00:00 2001
From: ilan-gold <ilanbassgold@gmail.com>
Date: Wed, 11 Dec 2024 10:55:03 +0100
Subject: [PATCH] (fix): `dtype` type handling

---
 xarray/core/indexing.py | 31 ++++++++++++++++++++++---------
 1 file changed, 22 insertions(+), 9 deletions(-)

diff --git a/xarray/core/indexing.py b/xarray/core/indexing.py
index 775b65b5144..722ac6db4a8 100644
--- a/xarray/core/indexing.py
+++ b/xarray/core/indexing.py
@@ -1663,7 +1663,11 @@ class PandasIndexingAdapter(ExplicitlyIndexedNDArrayMixin):
     array: pd.Index
     _dtype: np.dtype | pd.api.extensions.ExtensionDtype
 
-    def __init__(self, array: pd.Index, dtype: DTypeLike = None):
+    def __init__(
+        self,
+        array: pd.Index,
+        dtype: DTypeLike | pd.api.extensions.ExtensionDtype | None = None,
+    ):
         from xarray.core.indexes import safe_cast_to_index
 
         self.array = safe_cast_to_index(array)
@@ -1675,22 +1679,26 @@ def __init__(self, array: pd.Index, dtype: DTypeLike = None):
             else:
                 self._dtype = get_valid_numpy_dtype(array)
         elif pd.api.types.is_extension_array_dtype(dtype):
-            cast(pd.api.extensions.ExtensionDtype, dtype)
-            self._dtype = dtype
+            self._dtype = cast(pd.api.extensions.ExtensionDtype, dtype)
         else:
-            self._dtype = np.dtype(dtype)
+            self._dtype = np.dtype(cast(DTypeLike, dtype))
 
     @property
-    def dtype(self) -> np.dtype:
+    def dtype(self) -> np.dtype | pd.api.extensions.ExtensionDtype:  # type: ignore[override]
         return self._dtype
 
     def __array__(
-        self, dtype: np.typing.DTypeLike = None, /, *, copy: bool | None = None
+        self,
+        dtype: np.typing.DTypeLike | pd.api.extensions.ExtensionDtype | None = None,
+        /,
+        *,
+        copy: bool | None = None,
     ) -> np.ndarray:
         if dtype is None:
             dtype = self.dtype
         if pd.api.types.is_extension_array_dtype(dtype):
             dtype = get_valid_numpy_dtype(self.array)
+        dtype = cast(np.dtype, dtype)
         array = self.array
         if isinstance(array, pd.PeriodIndex):
             with suppress(AttributeError):
@@ -1726,7 +1734,7 @@ def _convert_scalar(self, item) -> np.ndarray:
             dtype = self.dtype
             if pd.api.types.is_extension_array_dtype(dtype):
                 dtype = get_valid_numpy_dtype(self.array)
-            item = np.asarray(item, dtype=dtype)
+            item = np.asarray(item, dtype=cast(np.dtype, dtype))
 
         # as for numpy.ndarray indexing, we always want the result to be
         # a NumPy array.
@@ -1846,19 +1854,24 @@ class PandasMultiIndexingAdapter(PandasIndexingAdapter):
     def __init__(
         self,
         array: pd.MultiIndex,
-        dtype: DTypeLike = None,
+        dtype: DTypeLike | pd.api.extensions.ExtensionDtype | None = None,
         level: str | None = None,
     ):
         super().__init__(array, dtype)
         self.level = level
 
     def __array__(
-        self, dtype: np.typing.DTypeLike = None, /, *, copy: bool | None = None
+        self,
+        dtype: DTypeLike | pd.api.extensions.ExtensionDtype | None = None,
+        /,
+        *,
+        copy: bool | None = None,
     ) -> np.ndarray:
         if dtype is None:
             dtype = self.dtype
         if pd.api.types.is_extension_array_dtype(dtype):
             dtype = get_valid_numpy_dtype(self.array)
+        dtype = cast(np.dtype, dtype)
         if self.level is not None:
             return np.asarray(
                 self.array.get_level_values(self.level).values, dtype=dtype