GH571 Update typehint when creating a Series from an empty list (#1029)

* GH571 Update typehint when creating a Series from an empty list

* GH571 Change import source of Never to typing_extensions

* GH571 PR feedback

Author: loicdiridollou

pandas-stubs/core/series.pyi

@@ -241,6 +241,16 @@ class Series(IndexOpsMixin[S1], NDFrame):
         copy: bool = ...,
     ) -> Series[float]: ...
     @overload
+    def __new__(  # type: ignore[overload-overlap]
+        cls,
+        data: Sequence[Never],
+        index: Axes | None = ...,
+        *,
+        dtype: Dtype = ...,
+        name: Hashable = ...,
+        copy: bool = ...,
+    ) -> Series[Any]: ...
+    @overload
     def __new__(
         cls,
         data: (

tests/test_frame.py

@@ -7,6 +7,7 @@
     Iterator,
     Mapping,
     MutableMapping,
+    Sequence,
 )
 import csv
 import datetime
@@ -38,6 +39,7 @@
 from pandas.core.series import Series
 import pytest
 from typing_extensions import (
+    Never,
     TypeAlias,
     assert_never,
     assert_type,
@@ -3566,3 +3568,12 @@ class MyDict(TypedDict):
     my_dict = MyDict(a="", b="")
     sr = pd.Series(my_dict)
     check(assert_type(sr, pd.Series), pd.Series)
+
+
+def test_series_empty_dtype() -> None:
+    """Test for the creation of a Series from an empty list GH571 to map to a Series[Any]."""
+    new_tab: Sequence[Never] = []  # need to be typehinted to please mypy
+    check(assert_type(pd.Series(new_tab), "pd.Series[Any]"), pd.Series)
+    check(assert_type(pd.Series([]), "pd.Series[Any]"), pd.Series)
+    # ensure that an empty string does not get matched to Sequence[Never]
+    check(assert_type(pd.Series(""), "pd.Series[str]"), pd.Series)