BUG fixes for date_range boundaries

doc/source/whatsnew/v2.2.0.rst

@@ -892,6 +892,8 @@ Other
 - Bug in :func:`DataFrame.describe` when formatting percentiles in the resulting percentile 99.999% is rounded to 100% (:issue:`55765`)
 - Bug in :func:`cut` and :func:`qcut` with ``datetime64`` dtype values with non-nanosecond units incorrectly returning nanosecond-unit bins (:issue:`56101`)
 - Bug in :func:`cut` incorrectly allowing cutting of timezone-aware datetimes with timezone-naive bins (:issue:`54964`)
+- Bug in :func:`date_range` where a timestamp out of the valid range would be produced with a negative ``freq`` parameter (:issue:`56147`)
+- Bug in :func:`date_range` where the last valid timestamp would sometimes not be produced (:issue:`56134`)
 - Bug in :func:`infer_freq` and :meth:`DatetimeIndex.inferred_freq` with weekly frequencies and non-nanosecond resolutions (:issue:`55609`)
 - Bug in :meth:`DataFrame.apply` where passing ``raw=True`` ignored ``args`` passed to the applied function (:issue:`55009`)
 - Bug in :meth:`DataFrame.from_dict` which would always sort the rows of the created :class:`DataFrame`.  (:issue:`55683`)

pandas/core/arrays/datetimes.py

@@ -2763,12 +2763,12 @@ def _generate_range(
     if start and not offset.is_on_offset(start):
         # Incompatible types in assignment (expression has type "datetime",
         # variable has type "Optional[Timestamp]")
-        start = offset.rollforward(start)  # type: ignore[assignment]
 
-    elif end and not offset.is_on_offset(end):
-        # Incompatible types in assignment (expression has type "datetime",
-        # variable has type "Optional[Timestamp]")
-        end = offset.rollback(end)  # type: ignore[assignment]
+        # GH #56147 account for negative direction and range bounds
+        if offset.n >= 0:
+            start = offset.rollforward(start)  # type: ignore[assignment]
+        else:
+            start = offset.rollback(start)  # type: ignore[assignment]
 
     # Unsupported operand types for < ("Timestamp" and "None")
     if periods is None and end < start and offset.n >= 0:  # type: ignore[operator]

pandas/tests/indexes/datetimes/test_date_range.py

@@ -1539,6 +1539,21 @@ def test_date_range_year_end(self, unit):
         )
         tm.assert_index_equal(rng, exp)
 
+    def test_date_range_partial_day_year_end(self, unit):
+        # GH#56134
+        rng = date_range(
+            start="2021-12-31 00:00:01",
+            end="2023-10-31 00:00:00",
+            freq="YE",
+            unit=unit,
+        )
+        exp = DatetimeIndex(
+            ["2021-12-31 00:00:01", "2022-12-31 00:00:01"],
+            dtype=f"M8[{unit}]",
+            freq="YE",
+        )
+        tm.assert_index_equal(rng, exp)
+
     def test_date_range_negative_freq_year_end(self, unit):
         # GH#11018
         rng = date_range("2011-12-31", freq="-2YE", periods=3, unit=unit)
@@ -1548,6 +1563,21 @@ def test_date_range_negative_freq_year_end(self, unit):
         tm.assert_index_equal(rng, exp)
         assert rng.freq == "-2YE"
 
+    def test_date_range_negative_freq_year_end_inbounds(self, unit):
+        # GH#56147
+        rng = date_range(
+            start="2023-10-31 00:00:00",
+            end="2021-10-31 00:00:00",
+            freq="-1YE",
+            unit=unit,
+        )
+        exp = DatetimeIndex(
+            ["2022-12-31 00:00:00", "2021-12-31 00:00:00"],
+            dtype=f"M8[{unit}]",
+            freq="-1YE",
+        )
+        tm.assert_index_equal(rng, exp)
+
     def test_date_range_business_year_end_year(self, unit):
         # see GH#9313
         rng = date_range("1/1/2013", "7/1/2017", freq="BYE", unit=unit)