BUG: #35830 Restore index & slice by date to DatetimeIndex

pandas/core/arrays/datetimelike.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from datetime import datetime, timedelta
+from datetime import date, datetime, time, timedelta
 import operator
 from typing import (
     TYPE_CHECKING,
@@ -552,6 +552,11 @@ def _validate_scalar(
         -------
         self._scalar_type or NaT
         """
+
+        if type(value) == date:
+            # GH35830
+            value = datetime.combine(value, time.min)
+
         if isinstance(value, str):
             # NB: Careful about tzawareness
             try:

pandas/core/indexes/datetimes.py

@@ -646,6 +646,10 @@ def get_loc(self, key, method=None, tolerance=None):
         if is_valid_nat_for_dtype(key, self.dtype):
             key = NaT
 
+        if type(key) == date:
+            # GH35830
+            key = datetime.combine(key, time.min)
+
         if isinstance(key, self._data._recognized_scalars):
             # needed to localize naive datetimes
             self._deprecate_mismatched_indexing(key)

pandas/tests/indexing/test_loc.py

@@ -1,5 +1,5 @@
 """ test label based indexing with loc """
-from datetime import datetime, time, timedelta
+from datetime import date, datetime, time, timedelta
 from io import StringIO
 import re
 
@@ -2130,3 +2130,13 @@ def test_loc_iloc_setitem_with_listlike(self, size, array_fn):
         ser = Series(0, index=list("abcde"), dtype=object)
         ser.iloc[0] = arr
         tm.assert_series_equal(ser, expected)
+
+    def test_loc_getitem_date_objs_with_datetimeindex(self):
+        # GH35830
+        dates = [date(2000, 1, i) for i in (1, 2, 5)]
+        values = [1, 2, 3]
+        s = Series(values, dates)
+        i = 1
+        expected = values[i]
+        result = s.loc[dates[i]]
+        assert result == expected