Fix DataFrame from Series with different CategoricalIndexes (#14157)

closes #14130

Authors:
  - Matthew Roeschke (https://github.com/mroeschke)

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

URL: #14157

python/cudf/cudf/core/indexed_frame.py

@@ -5438,6 +5438,13 @@ def _is_same_dtype(lhs_dtype, rhs_dtype):
     # for matching column dtype.
     if lhs_dtype == rhs_dtype:
         return True
+    elif (
+        is_categorical_dtype(lhs_dtype)
+        and is_categorical_dtype(rhs_dtype)
+        and lhs_dtype.categories.dtype == rhs_dtype.categories.dtype
+    ):
+        # OK if categories are not all the same
+        return True
     elif (
         is_categorical_dtype(lhs_dtype)
         and not is_categorical_dtype(rhs_dtype)

python/cudf/cudf/tests/test_dataframe.py

@@ -10408,6 +10408,19 @@ def test_dataframe_init_from_nested_dict():
     assert_eq(pdf, gdf)
 
 
+def test_init_from_2_categoricalindex_series_diff_categories():
+    s1 = cudf.Series(
+        [39, 6, 4], index=cudf.CategoricalIndex(["female", "male", "unknown"])
+    )
+    s2 = cudf.Series(
+        [2, 152, 2, 242, 150],
+        index=cudf.CategoricalIndex(["f", "female", "m", "male", "unknown"]),
+    )
+    result = cudf.DataFrame([s1, s2])
+    expected = pd.DataFrame([s1.to_pandas(), s2.to_pandas()])
+    assert_eq(result, expected, check_dtype=False)
+
+
 def test_data_frame_values_no_cols_but_index():
     result = cudf.DataFrame(index=range(5)).values
     expected = pd.DataFrame(index=range(5)).values