change after review

Author: makbigc

pandas/core/reshape/merge.py

@@ -8,51 +8,19 @@
 
 import numpy as np
 
-<<<<<<< HEAD
 from pandas._libs import hashtable as libhashtable, join as libjoin, lib
 import pandas.compat as compat
 from pandas.compat import filter, lzip, map, range, zip
 from pandas.errors import MergeError
-=======
-from pandas import (Categorical, DataFrame,
-                    Index, MultiIndex, Timedelta, Series)
-from pandas.core.arrays.categorical import _recode_for_categories
-from pandas.core.frame import _merge_doc
-from pandas.core.dtypes.common import (
-    is_datetime64tz_dtype,
-    is_datetime64_dtype,
-    needs_i8_conversion,
-    is_int64_dtype,
-    is_array_like,
-    is_categorical_dtype,
-    is_integer_dtype,
-    is_float_dtype,
-    is_number,
-    is_numeric_dtype,
-    is_integer,
-    is_extension_array_dtype,
-    is_int_or_datetime_dtype,
-    is_dtype_equal,
-    is_bool,
-    is_bool_dtype,
-    is_list_like,
-    is_datetimelike,
-    ensure_int64,
-    ensure_float64,
-    ensure_object,
-    _get_dtype)
-from pandas.core.dtypes.missing import na_value_for_dtype
-from pandas.core.internals import (items_overlap_with_suffix,
-                                   concatenate_block_managers)
->>>>>>> fix bug #GH23020
 from pandas.util._decorators import Appender, Substitution
 
 from pandas.core.dtypes.common import (
     ensure_float64, ensure_int64, ensure_object, is_array_like, is_bool,
     is_bool_dtype, is_categorical_dtype, is_datetime64_dtype,
     is_datetime64tz_dtype, is_datetimelike, is_dtype_equal, is_float_dtype,
     is_int64_dtype, is_int_or_datetime_dtype, is_integer, is_integer_dtype,
-    is_list_like, is_number, is_numeric_dtype, needs_i8_conversion)
+    is_list_like, is_number, is_numeric_dtype, is_extension_array_dtype,
+    needs_i8_conversion)
 from pandas.core.dtypes.missing import isnull, na_value_for_dtype
 
 from pandas import Categorical, DataFrame, Index, MultiIndex, Series, Timedelta
@@ -1551,10 +1519,12 @@ def _factorize_keys(lk, rk, sort=True):
 
         lk = ensure_int64(lk.codes)
         rk = ensure_int64(rk)
-    elif is_extension_array_dtype(lk) and is_extension_array_dtype(rk):
+    elif (is_extension_array_dtype(lk) and
+          is_extension_array_dtype(rk) and
+          lk.dtype == rk.dtype):
         klass = libhashtable.Factorizer
-        lk = ensure_object(lk)
-        rk = ensure_object(rk)
+        lk, _ = lk._values_for_factorize()
+        rk, _ = rk._values_for_factorize()
     elif is_int_or_datetime_dtype(lk) and is_int_or_datetime_dtype(rk):
         klass = libhashtable.Int64Factorizer
         lk = ensure_int64(com.values_from_object(lk))

pandas/tests/extension/base/reshaping.py

@@ -170,3 +170,11 @@ def test_merge(self, data, na_value):
                  [data[0], data[0], data[1], data[2], na_value],
                  dtype=data.dtype)})
         self.assert_frame_equal(res, exp[['ext', 'int1', 'key', 'int2']])
+
+    def test_merge_on_int_array(self, df_merge_on_int_array):
+        # GH  23020
+        result = pd.merge(df_merge_on_int_array, df_merge_on_int_array, on='A')
+        expected = pd.DataFrame({'A': pd.Series([1, 2, np.nan], dtype='Int64'),
+                                 'B_x': 1,
+                                 'B_y': 1})
+        self.assert_frame_equal(result, expected, check_dtype=True)

pandas/tests/extension/conftest.py

@@ -1,3 +1,5 @@
+import pandas as pd
+import numpy as np
 import operator
 
 import pytest
@@ -104,3 +106,9 @@ def data_for_grouping():
 def box_in_series(request):
     """Whether to box the data in a Series"""
     return request.param
+
+
+@pytest.fixture
+def df_merge_on_int_array():
+    return pd.DataFrame({'A': pd.Series([1, 2, np.nan], dtype='Int64'),
+                         'B': 1})

pandas/tests/reshape/merge/test_merge.py

@@ -1842,16 +1842,6 @@ def test_merging_with_bool_or_int_cateorical_column(self, category_column,
             CDT(categories, ordered=ordered))
         assert_frame_equal(expected, result)
 
-    def test_merge_on_int_array(self):
-        # GH  23020
-        df = pd.DataFrame({'A': pd.Series([1, 2, np.nan], dtype='Int64'),
-                           'B': 1})
-        result = pd.merge(df, df, on='A')
-        expected = pd.DataFrame({'A': pd.Series([1, 2, np.nan], dtype='Int64'),
-                                 'B_x': 1,
-                                 'B_y': 1})
-        assert_frame_equal(result, expected, check_dtype=True)
-
 
 @pytest.fixture
 def left_df():