BUG: date_range inclusive parameter behavior doesn't match interval notation

doc/source/whatsnew/v2.1.3.rst

@@ -21,6 +21,7 @@ Fixed regressions
 Bug fixes
 ~~~~~~~~~
 - Bug in :meth:`DatetimeIndex.diff` raising ``TypeError`` (:issue:`55080`)
+- Fixed bug in :meth:`DatetimeArray._generate_range` where ``inclusive`` argument behavior did not match interval notation (:issue:`55293`,:issue:`46331`)
 - Bug in :meth:`Index.isin` raising for Arrow backed string and ``None`` value (:issue:`55821`)
 - Fix :func:`read_parquet` and :func:`read_feather` for `CVE-2023-47248 <https://www.cve.org/CVERecord?id=CVE-2023-47248>`__ (:issue:`55894`)
 

pandas/core/arrays/datetimes.py

@@ -508,17 +508,11 @@ def _generate_range(  # type: ignore[override]
                 #  to overflow and cast to e.g. f8, but if it does we need to cast
                 i8values = i8values.astype("i8")
 
-        if start == end:
-            if not left_inclusive and not right_inclusive:
-                i8values = i8values[1:-1]
-        else:
-            start_i8 = Timestamp(start)._value
-            end_i8 = Timestamp(end)._value
-            if not left_inclusive or not right_inclusive:
-                if not left_inclusive and len(i8values) and i8values[0] == start_i8:
-                    i8values = i8values[1:]
-                if not right_inclusive and len(i8values) and i8values[-1] == end_i8:
-                    i8values = i8values[:-1]
+        if not left_inclusive:
+            i8values = i8values[1:]
+
+        if not right_inclusive:
+            i8values = i8values[:-1]
 
         dt64_values = i8values.view(f"datetime64[{unit}]")
         dtype = tz_to_dtype(tz, unit=unit)

pandas/tests/indexes/datetimes/test_date_range.py

@@ -49,29 +49,22 @@
 
 
 def _get_expected_range(
-    begin_to_match,
-    end_to_match,
     both_range,
     inclusive_endpoints,
 ):
     """Helper to get expected range from a both inclusive range"""
-    left_match = begin_to_match == both_range[0]
-    right_match = end_to_match == both_range[-1]
-
-    if inclusive_endpoints == "left" and right_match:
-        expected_range = both_range[:-1]
-    elif inclusive_endpoints == "right" and left_match:
-        expected_range = both_range[1:]
-    elif inclusive_endpoints == "neither" and left_match and right_match:
-        expected_range = both_range[1:-1]
-    elif inclusive_endpoints == "neither" and right_match:
+    if inclusive_endpoints == "left":
         expected_range = both_range[:-1]
-    elif inclusive_endpoints == "neither" and left_match:
+    elif inclusive_endpoints == "right":
         expected_range = both_range[1:]
     elif inclusive_endpoints == "both":
         expected_range = both_range[:]
+    elif inclusive_endpoints == "neither":
+        expected_range = both_range[1:-1]
     else:
-        expected_range = both_range[:]
+        raise ValueError(
+            "Inclusive has to be either 'both', 'neither', 'left' or 'right'"
+        )
 
     return expected_range
 
@@ -591,12 +584,29 @@ def test_range_closed(self, freq, tz, inclusive_endpoints_fixture):
         begin = Timestamp("2011/1/1", tz=tz)
         end = Timestamp("2014/1/1", tz=tz)
 
+        result_range = date_range(
+            begin, end, inclusive=inclusive_endpoints_fixture, freq=freq
+        )
+        both_range = date_range(begin, end, inclusive="both", freq=freq)
+        expected_range = _get_expected_range(both_range, inclusive_endpoints_fixture)
+
+        tm.assert_index_equal(expected_range, result_range)
+
+    @pytest.mark.parametrize("freq", ["1D", "3D", "2ME", "7W", "3h", "YE"])
+    def test_range_closed_with_tz_aware_start_end(
+        self, freq, inclusive_endpoints_fixture
+    ):
+        # GH12409, GH12684
+        begin = Timestamp("2011/1/1", tz="US/Eastern")
+        end = Timestamp("2014/1/1", tz="US/Eastern")
+
         result_range = date_range(
             begin, end, inclusive=inclusive_endpoints_fixture, freq=freq
         )
         both_range = date_range(begin, end, inclusive="both", freq=freq)
         expected_range = _get_expected_range(
-            begin, end, both_range, inclusive_endpoints_fixture
+            both_range,
+            inclusive_endpoints_fixture,
         )
 
         tm.assert_index_equal(expected_range, result_range)
@@ -607,8 +617,8 @@ def test_range_with_tz_closed_with_tz_aware_start_end(
     ):
         begin = Timestamp("2011/1/1")
         end = Timestamp("2014/1/1")
-        begintz = Timestamp("2011/1/1", tz="US/Eastern")
-        endtz = Timestamp("2014/1/1", tz="US/Eastern")
+        # begintz = Timestamp("2011/1/1", tz="US/Eastern")
+        # endtz = Timestamp("2014/1/1", tz="US/Eastern")
 
         result_range = date_range(
             begin,
@@ -621,8 +631,6 @@ def test_range_with_tz_closed_with_tz_aware_start_end(
             begin, end, inclusive="both", freq=freq, tz="US/Eastern"
         )
         expected_range = _get_expected_range(
-            begintz,
-            endtz,
             both_range,
             inclusive_endpoints_fixture,
         )
@@ -656,18 +664,9 @@ def test_range_closed_boundary(self, inclusive_endpoints_fixture):
             inclusive=inclusive_endpoints_fixture,
         )
 
-        expected_right = both_boundary
-        expected_left = both_boundary
-        expected_both = both_boundary
-
-        if inclusive_endpoints_fixture == "right":
-            expected_left = both_boundary[1:]
-        elif inclusive_endpoints_fixture == "left":
-            expected_right = both_boundary[:-1]
-        elif inclusive_endpoints_fixture == "both":
-            expected_right = both_boundary[1:]
-            expected_left = both_boundary[:-1]
-
+        expected_right = both_boundary[1:]
+        expected_left = both_boundary[:-1]
+        expected_both = both_boundary[:]
         expected_neither = both_boundary[1:-1]
 
         tm.assert_index_equal(right_boundary, expected_right)
@@ -748,10 +747,7 @@ def test_range_where_start_equal_end(self, inclusive_endpoints_fixture):
         )
 
         both_range = date_range(start=start, end=end, freq="D", inclusive="both")
-        if inclusive_endpoints_fixture == "neither":
-            expected = both_range[1:-1]
-        elif inclusive_endpoints_fixture in ("left", "right", "both"):
-            expected = both_range[:]
+        expected = _get_expected_range(both_range, inclusive_endpoints_fixture)
 
         tm.assert_index_equal(result, expected)
 
@@ -1102,7 +1098,7 @@ def test_bdays_and_open_boundaries(self, inclusive):
 
         bday_start = "2018-07-23"  # Monday
         bday_end = "2018-07-27"  # Friday
-        expected = date_range(bday_start, bday_end, freq="D")
+        expected = date_range(bday_start, bday_end, freq="D", inclusive=inclusive)
         tm.assert_index_equal(result, expected)
         # Note: we do _not_ expect the freqs to match here