BUG: concat(axis=1) ignoring sort parameter for DatetimeIndex (#55085)

BUG: concat ignoring sort parameter for DatetimeIndex

Author: lukemanley

doc/source/whatsnew/v2.2.0.rst

@@ -247,8 +247,8 @@ Groupby/resample/rolling
 
 Reshaping
 ^^^^^^^^^
+- Bug in :func:`concat` ignoring ``sort`` parameter when passed :class:`DatetimeIndex` indexes (:issue:`54769`)
 - Bug in :func:`merge` returning columns in incorrect order when left and/or right is empty (:issue:`51929`)
--
 
 Sparse
 ^^^^^^

pandas/core/indexes/api.py

@@ -288,7 +288,6 @@ def _find_common_index_dtype(inds):
             raise TypeError("Cannot join tz-naive with tz-aware DatetimeIndex")
 
         if len(dtis) == len(indexes):
-            sort = True
             result = indexes[0]
 
         elif len(dtis) > 1:

pandas/tests/reshape/concat/test_datetimes.py

@@ -77,23 +77,23 @@ def test_concat_datetime_timezone(self):
 
         exp_idx = DatetimeIndex(
             [
-                "2010-12-31 15:00:00+00:00",
-                "2010-12-31 16:00:00+00:00",
-                "2010-12-31 17:00:00+00:00",
                 "2010-12-31 23:00:00+00:00",
                 "2011-01-01 00:00:00+00:00",
                 "2011-01-01 01:00:00+00:00",
+                "2010-12-31 15:00:00+00:00",
+                "2010-12-31 16:00:00+00:00",
+                "2010-12-31 17:00:00+00:00",
             ]
         )
 
         expected = DataFrame(
             [
-                [np.nan, 1],
-                [np.nan, 2],
-                [np.nan, 3],
                 [1, np.nan],
                 [2, np.nan],
                 [3, np.nan],
+                [np.nan, 1],
+                [np.nan, 2],
+                [np.nan, 3],
             ],
             index=exp_idx,
             columns=["a", "b"],