BUG: date_range doesn't propagate ambigous=False to tz_localize

doc/source/whatsnew/v1.2.0.rst

@@ -71,7 +71,7 @@ Timedelta
 Timezones
 ^^^^^^^^^
 
--
+- Bug in :func:`date_range` was raising AmbiguousTimeError for valid input with `ambiguous=False` (:issue:`35297`)
 -
 
 

pandas/core/arrays/datetimes.py

@@ -418,9 +418,9 @@ def _generate_range(
                 # index is localized datetime64 array -> have to convert
                 # start/end as well to compare
                 if start is not None:
-                    start = start.tz_localize(tz).asm8
+                    start = start.tz_localize(tz, ambiguous, nonexistent).asm8
                 if end is not None:
-                    end = end.tz_localize(tz).asm8
+                    end = end.tz_localize(tz, ambiguous, nonexistent).asm8
         else:
             # Create a linearly spaced date_range in local time
             # Nanosecond-granularity timestamps aren't always correctly

pandas/tests/indexes/datetimes/test_constructors.py

@@ -787,6 +787,65 @@ def test_construction_with_nat_and_tzlocal(self):
         expected = DatetimeIndex([Timestamp("2018", tz=tz), pd.NaT])
         tm.assert_index_equal(result, expected)
 
+    def test_constructor_with_ambiguous_keyword_arg(self):
+        # GH 35297
+
+        expected = DatetimeIndex(
+            ["2020-11-01 01:00:00", "2020-11-02 01:00:00"],
+            dtype="datetime64[ns, America/New_York]",
+            freq="D",
+            ambiguous=False,
+        )
+
+        # ambiguous keyword in start
+        timezone = "America/New_York"
+        start = pd.Timestamp(year=2020, month=11, day=1, hour=1).tz_localize(
+            timezone, ambiguous=False
+        )
+        result = pd.date_range(start=start, periods=2, ambiguous=False)
+        tm.assert_index_equal(result, expected)
+
+        # ambiguous keyword in end
+        timezone = "America/New_York"
+        end = pd.Timestamp(year=2020, month=11, day=2, hour=1).tz_localize(
+            timezone, ambiguous=False
+        )
+        result = pd.date_range(end=end, periods=2, ambiguous=False)
+        tm.assert_index_equal(result, expected)
+
+    def test_constructor_with_nonexistent_keyword_arg(self):
+        # GH 35297
+
+        timezone = "Europe/Warsaw"
+
+        # nonexistent keyword in start
+        start = pd.Timestamp("2015-03-29 02:30:00").tz_localize(
+            timezone, nonexistent="shift_forward"
+        )
+        result = pd.date_range(start=start, periods=2, freq="H")
+        expected = DatetimeIndex(
+            [
+                pd.Timestamp("2015-03-29 03:00:00+02:00", tz=timezone),
+                pd.Timestamp("2015-03-29 04:00:00+02:00", tz=timezone),
+            ]
+        )
+
+        tm.assert_index_equal(result, expected)
+
+        # nonexistent keyword in end
+        end = pd.Timestamp("2015-03-29 02:30:00").tz_localize(
+            timezone, nonexistent="shift_forward"
+        )
+        result = pd.date_range(end=end, periods=2, freq="H")
+        expected = DatetimeIndex(
+            [
+                pd.Timestamp("2015-03-29 01:00:00+01:00", tz=timezone),
+                pd.Timestamp("2015-03-29 03:00:00+02:00", tz=timezone),
+            ]
+        )
+
+        tm.assert_index_equal(result, expected)
+
     def test_constructor_no_precision_raises(self):
         # GH-24753, GH-24739