BUG: _validate_setitem_value fails to raise for PandasArray #51044

pandas/core/arrays/numpy_.py

@@ -15,7 +15,10 @@
 from pandas.compat.numpy import function as nv
 
 from pandas.core.dtypes.astype import astype_array
-from pandas.core.dtypes.cast import construct_1d_object_array_from_listlike
+from pandas.core.dtypes.cast import (
+    construct_1d_object_array_from_listlike,
+    np_can_hold_element,
+)
 from pandas.core.dtypes.common import pandas_dtype
 from pandas.core.dtypes.dtypes import NumpyEADtype
 from pandas.core.dtypes.missing import isna
@@ -507,6 +510,53 @@ def to_numpy(
 
         return result
 
+    def _validate_setitem_value(self, value):
+        if type(value) == int:
+            try:
+                np_can_hold_element(self.dtype, value)
+            except Exception:
+                pass
+            return value
+        elif type(value) == float:
+            if (
+                self.dtype
+                in [
+                    NumpyEADtype("float32"),
+                    NumpyEADtype("float64"),
+                    NumpyEADtype("object"),
+                ]
+                or self.dtype is None
+            ):
+                return value
+        elif type(value) not in [int, float] and (
+            self.dtype
+            not in [
+                NumpyEADtype("int64"),
+                NumpyEADtype("float64"),
+                NumpyEADtype("uint16"),
+                NumpyEADtype("object"),
+            ]
+            or lib.is_list_like(value)
+        ):
+            return value
+        if self.dtype is None:
+            return value
+        if not isinstance(self.dtype, NumpyEADtype):
+            return value
+        if (
+            NumpyEADtype(type(value)) == NumpyEADtype(self.dtype)
+            or NumpyEADtype(type(value)) == self.dtype
+        ):
+            return value
+        if self.dtype == NumpyEADtype("object"):
+            return value
+
+        raise TypeError(
+            "value cannot be inserted without changing the dtype. value:"
+            f"{value}, type(value): {type(value)}, NumpyEADtype(type(value)):"
+            f"  {NumpyEADtype(type(value))}, self.dtype:  {self.dtype}"
+        )
+
     # ------------------------------------------------------------------------
     # Ops
 

pandas/tests/arrays/numpy_/test_numpy.py

@@ -279,7 +279,7 @@ def test_setitem_no_coercion():
 
     # With a value that we do coerce, check that we coerce the value
     #  and not the underlying array.
-    arr[0] = 2.5
+    arr[0] = 2
     assert isinstance(arr[0], (int, np.integer)), type(arr[0])
 
 
@@ -295,7 +295,7 @@ def test_setitem_preserves_views():
     assert view2[0] == 9
     assert view3[0] == 9
 
-    arr[-1] = 2.5
+    arr[-1] = 2
     view1[-1] = 5
     assert arr[-1] == 5
 
@@ -322,3 +322,12 @@ def test_factorize_unsigned():
     tm.assert_numpy_array_equal(res_codes, exp_codes)
 
     tm.assert_extension_array_equal(res_unique, NumpyExtensionArray(exp_unique))
+
+
+def test_array_validate_setitem_value():
+    # Issue# 51044
+    arr = pd.Series(range(5)).array
+    with pytest.raises(TypeError, match="str"):
+        arr._validate_setitem_value("foo")
+    with pytest.raises(TypeError, match="float"):
+        arr._validate_setitem_value(1.5)