GH804 Index names typing

Author: loicdiridollou

pandas-stubs/core/indexes/base.pyi

@@ -49,6 +49,7 @@ from pandas._typing import (
     Label,
     Level,
     NaPosition,
+    SequenceNotStr,
     TimedeltaDtypeArg,
     TimestampDtypeArg,
     np_ndarray_anyint,
@@ -288,9 +289,9 @@ class Index(IndexOpsMixin[S1]):
     @name.setter
     def name(self, value) -> None: ...
     @property
-    def names(self) -> list[_str]: ...
+    def names(self) -> SequenceNotStr: ...
     @names.setter
-    def names(self, names: list[_str]): ...
+    def names(self, names: SequenceNotStr): ...
     def set_names(self, names, *, level=..., inplace: bool = ...): ...
     @overload
     def rename(self, name, inplace: Literal[False] = False) -> Self: ...

tests/test_indexes.py

@@ -1160,3 +1160,14 @@ def test_value_counts() -> None:
         pd.Series,
         float,
     )
+
+
+def test_index_naming() -> None:
+    """Test that we can set the names of an index as a hashable."""
+    df = pd.DataFrame({"a": ["a", "b", "c"], "i": [10, 11, 12]})
+
+    df.index.names = ["idx"]
+
+    df.index.names = ("idx2",)
+    df.index.names = [None]
+    df.index.names = (None,)