BUG: Fix is_signed_integer_dtype to handle abstract floating types (GH 62018)

pandas/core/dtypes/common.py

@@ -840,6 +840,10 @@ def is_signed_integer_dtype(arr_or_dtype) -> bool:
     >>> is_signed_integer_dtype(np.array([1, 2], dtype=np.uint32))  # unsigned
     False
     """
+    if isinstance(arr_or_dtype, type) and issubclass(
+        arr_or_dtype, (np.floating, np.inexact, np.generic)
+    ):
+        return False
     return _is_dtype_type(
         arr_or_dtype, _classes_and_not_datetimelike(np.signedinteger)
     ) or _is_dtype(

pandas/tests/dtypes/test_dtypes.py

@@ -17,6 +17,7 @@
     is_dtype_equal,
     is_interval_dtype,
     is_period_dtype,
+    is_signed_integer_dtype,
     is_string_dtype,
 )
 from pandas.core.dtypes.dtypes import (
@@ -1150,6 +1151,13 @@ def test_is_bool_dtype(dtype, expected):
     assert result is expected
 
 
+def test_is_signed_integer_dtype_with_abstract_types():
+    # GH 62018
+    assert is_signed_integer_dtype(np.floating) is False
+    assert is_signed_integer_dtype(np.inexact) is False
+    assert is_signed_integer_dtype(np.generic) is False
+
+
 def test_is_bool_dtype_sparse():
     result = is_bool_dtype(Series(SparseArray([True, False])))
     assert result is True