setitem exceptions for complex raise ValueError

In certain cases where Python throws a TypeError for complex values where it would throw ValueError for real values, transform exception to ValueError.

Signed-off-by: Michael Tiemann <72577720+MichaelTiemannOSC@users.noreply.github.com>

Author: MichaelTiemannOSC

pandas/core/arrays/_mixins.py

@@ -259,7 +259,13 @@ def shift(self, periods: int = 1, fill_value=None):
     def __setitem__(self, key, value) -> None:
         key = check_array_indexer(self, key)
         value = self._validate_setitem_value(value)
-        self._ndarray[key] = value
+        try:
+            self._ndarray[key] = value
+        except TypeError as exc:
+            # Don't let Python's handling of `complex` make extra complexity for Pandas
+            if self._ndarray.dtype.kind == "c":
+                raise ValueError(*(x.replace("real", "complex") for x in exc.args))
+            raise exc
 
     def _validate_setitem_value(self, value):
         return value

pandas/tests/extension/base/setitem.py

@@ -343,8 +343,8 @@ def test_setitem_slice_array(self, data):
 
     def test_setitem_scalar_key_sequence_raise(self, data):
         arr = data[:5].copy()
-        # complex128 data raises TypeError; other numeric types raise ValueError
-        with pytest.raises((ValueError, TypeError)):
+        msg = ""  # messages vary by subclass, so we do not test it
+        with pytest.raises(ValueError, match=msg):
             arr[0] = arr[[0, 1]]
 
     def test_setitem_preserves_views(self, data):