Fix OverflowError localizing dates at the year 1 and 9999 edges

dateparser/utils/__init__.py

@@ -8,7 +8,7 @@
 import warnings
 from collections import OrderedDict
 from collections.abc import Callable, Mapping
-from datetime import datetime, tzinfo
+from datetime import MINYEAR, datetime, timedelta, tzinfo
 from datetime import timezone as dt_timezone
 from typing import TYPE_CHECKING, Any, Literal, TypeVar
 
@@ -138,7 +138,14 @@ def localize_timezone(date_time: datetime, tz_string: str) -> datetime:
     tz = get_timezone_from_tz_string(tz_string)
 
     if hasattr(tz, "localize"):
-        date_time = tz.localize(date_time)
+        try:
+            date_time = tz.localize(date_time)
+        except OverflowError:
+            # pytz computes the UTC equivalent, which can fall outside the
+            # supported year range near its edges. The offset of a date 1
+            # day closer to the middle of the range is the same.
+            shift = timedelta(days=1 if date_time.year == MINYEAR else -1)
+            date_time = tz.localize(date_time + shift) - shift
     else:
         date_time = date_time.replace(tzinfo=tz)
 

tests/test_utils.py

@@ -320,3 +320,19 @@ def test_generate_time_span_without_base_date_or_settings_deprecated() -> None:
             datetime(2020, 1, 1),
             datetime(2020, 1, 31),
         )
+
+
+@pytest.mark.parametrize(
+    ("date", "tz_string", "offset"),
+    [
+        (datetime(1, 1, 1), "Asia/Tokyo", timedelta(hours=9, minutes=19)),
+        (datetime(9999, 12, 31, 23), "America/New_York", timedelta(hours=-5)),
+        (datetime(9999, 12, 31, 23), "Australia/Sydney", timedelta(hours=11)),
+    ],
+)
+def test_localize_timezone_range_edges(
+    date: datetime, tz_string: str, offset: timedelta
+) -> None:
+    tzaware_dt = localize_timezone(date, tz_string)
+    assert tzaware_dt.replace(tzinfo=None) == date
+    assert tzaware_dt.utcoffset() == offset