Make Series(dtype=object) raise in mode.pandas_compat with non string data (#17804)

closes #17752

Authors:
  - Matthew Roeschke (https://github.com/mroeschke)
  - GALI PREM SAGAR (https://github.com/galipremsagar)

Approvers:
  - GALI PREM SAGAR (https://github.com/galipremsagar)

URL: #17804

Author: mroeschke

python/cudf/cudf/core/column/column.py

@@ -2394,7 +2394,7 @@ def as_column(
     }:
         if isinstance(dtype, (cudf.CategoricalDtype, cudf.IntervalDtype)):
             dtype = dtype.to_pandas()
-        elif dtype == object:
+        elif dtype == object and not cudf.get_option("mode.pandas_compatible"):
             # Unlike pandas, interpret object as "str" instead of "python object"
             dtype = "str"
         ser = pd.Series(arbitrary, dtype=dtype)

python/cudf/cudf/tests/test_series.py

@@ -3021,6 +3021,12 @@ def test_roundtrip_series_plc_column(ps):
     assert_eq(expect, actual)
 
 
+def test_non_strings_dtype_object_pandas_compat_raises():
+    with cudf.option_context("mode.pandas_compatible", True):
+        with pytest.raises(TypeError):
+            cudf.Series([1], dtype=object)
+
+
 def test_series_dataframe_count_float():
     gs = cudf.Series([1, 2, 3, None, np.nan, 10], nan_as_null=False)
     ps = cudf.Series([1, 2, 3, None, np.nan, 10])