test, whatsnew

Author: jbrockmendel

doc/source/whatsnew/v1.2.0.rst

@@ -358,6 +358,7 @@ Indexing
 - Bug in :meth:`Index.sort_values` where, when empty values were passed, the method would break by trying to compare missing values instead of pushing them to the end of the sort order. (:issue:`35584`)
 - Bug in :meth:`Index.get_indexer` and :meth:`Index.get_indexer_non_unique` where int64 arrays are returned instead of intp. (:issue:`36359`)
 - Bug in :meth:`DataFrame.sort_index` where parameter ascending passed as a list on a single level index gives wrong result. (:issue:`32334`)
+- Bug in indexing with boolean masks on datetime-like values sometimes returning a view instead of a copy (:issue:`36210`)
 
 Missing
 ^^^^^^^

pandas/tests/series/indexing/test_boolean.py

@@ -1,7 +1,7 @@
 import numpy as np
 import pytest
 
-from pandas import Index, Series
+from pandas import Index, Series, date_range
 import pandas._testing as tm
 from pandas.core.indexing import IndexingError
 
@@ -128,3 +128,14 @@ def test_get_set_boolean_different_order(string_series):
     sel = string_series[ordered > 0]
     exp = string_series[string_series > 0]
     tm.assert_series_equal(sel, exp)
+
+
+def test_getitem_boolean_dt64_copies():
+    # GH#36210
+    dti = date_range("2016-01-01", periods=4, tz="US/Pacific")
+    key = np.array([True, True, False, False])
+
+    ser = Series(dti._data)
+
+    res = ser[key]
+    assert res._values._data.base is None