chore(python): Clean up some remnants of Python 3.8 support

.github/workflows/test-bytecode-parser.yml

@@ -17,7 +17,7 @@ jobs:
       fail-fast: false
       matrix:
         # Only the versions that are not already run as part of the regular test suite
-        python-version: ['3.9', '3.10']
+        python-version: ['3.10', '3.11']
 
     steps:
       - uses: actions/checkout@v4

docs/source/user-guide/installation.md

@@ -155,7 +155,7 @@ pip install 'polars[numpy,fsspec]'
 | style       | Style dataframes through the `style` namespace. |
 | timezone    | Timezone support[^note].                        |
 
-[^note]: Only needed if you are on Python < 3.9 or you are on Windows.
+[^note]: Only needed if you are on Windows.
 
 ### Rust
 

py-polars/polars/_utils/convert.py

@@ -8,9 +8,9 @@
     Any,
     Callable,
     NoReturn,
-    no_type_check,
     overload,
 )
+from zoneinfo import ZoneInfo, ZoneInfoNotFoundError
 
 from polars._utils.constants import (
     EPOCH,
@@ -22,7 +22,6 @@
     SECONDS_PER_HOUR,
     US_PER_SECOND,
 )
-from polars.dependencies import _ZONEINFO_AVAILABLE, zoneinfo
 
 if TYPE_CHECKING:
     from collections.abc import Sequence
@@ -161,38 +160,23 @@ def to_py_datetime(
 
     if time_zone is None:
         return EPOCH + td
-    elif _ZONEINFO_AVAILABLE:
+    else:
         dt = EPOCH_UTC + td
         return _localize_datetime(dt, time_zone)
-    else:
-        msg = "install polars[timezone] to handle datetimes with time zone information"
-        raise ImportError(msg)
 
 
 def _localize_datetime(dt: datetime, time_zone: str) -> datetime:
     # zone info installation should already be checked
+    tz: ZoneInfo | tzinfo
     try:
-        tz = string_to_zoneinfo(time_zone)
-    except zoneinfo.ZoneInfoNotFoundError:
+        tz = ZoneInfo(time_zone)
+    except ZoneInfoNotFoundError:
         # try fixed offset, which is not supported by ZoneInfo
         tz = _parse_fixed_tz_offset(time_zone)
 
     return dt.astimezone(tz)
 
 
-@no_type_check
-@lru_cache(None)
-def string_to_zoneinfo(key: str) -> Any:
-    """
-    Convert a time zone string to a Python ZoneInfo object.
-
-    This is a simple wrapper for the zoneinfo.ZoneInfo constructor.
-    The wrapper is useful because zoneinfo is not available on Python 3.8
-    and the backports module may not be installed.
-    """
-    return zoneinfo.ZoneInfo(key)
-
-
 # cache here as we have a single tz per column
 # and this function will be called on every conversion
 @lru_cache(16)

py-polars/polars/dependencies.py

@@ -20,7 +20,6 @@
 _PYARROW_AVAILABLE = True
 _PYDANTIC_AVAILABLE = True
 _PYICEBERG_AVAILABLE = True
-_ZONEINFO_AVAILABLE = True
 
 
 class _LazyModule(ModuleType):
@@ -150,7 +149,6 @@ def _lazy_import(module_name: str) -> tuple[ModuleType, bool]:
     import json
     import pickle
     import subprocess
-    import zoneinfo
 
     import altair
     import deltalake
@@ -182,11 +180,6 @@ def _lazy_import(module_name: str) -> tuple[ModuleType, bool]:
     pyarrow, _PYARROW_AVAILABLE = _lazy_import("pyarrow")
     pydantic, _PYDANTIC_AVAILABLE = _lazy_import("pydantic")
     pyiceberg, _PYICEBERG_AVAILABLE = _lazy_import("pyiceberg")
-    zoneinfo, _ZONEINFO_AVAILABLE = (
-        _lazy_import("zoneinfo")
-        if sys.version_info >= (3, 9)
-        else _lazy_import("backports.zoneinfo")
-    )
     gevent, _GEVENT_AVAILABLE = _lazy_import("gevent")
 
 
@@ -308,7 +301,6 @@ def import_optional(
     "pydantic",
     "pyiceberg",
     "pyarrow",
-    "zoneinfo",
     # lazy utilities
     "_check_for_numpy",
     "_check_for_pandas",
@@ -324,5 +316,4 @@ def import_optional(
     "_NUMPY_AVAILABLE",
     "_PANDAS_AVAILABLE",
     "_PYARROW_AVAILABLE",
-    "_ZONEINFO_AVAILABLE",
 ]

py-polars/polars/testing/parametric/strategies/data.py

@@ -6,6 +6,7 @@
 from collections.abc import Mapping
 from datetime import datetime, timedelta, timezone
 from typing import TYPE_CHECKING, Any, Literal
+from zoneinfo import ZoneInfo
 
 import hypothesis.strategies as st
 from hypothesis.errors import InvalidArgument
@@ -25,7 +26,6 @@
     U32_MAX,
     U64_MAX,
 )
-from polars._utils.convert import string_to_zoneinfo
 from polars.datatypes import (
     Array,
     Binary,
@@ -167,7 +167,7 @@ def datetimes(
     if time_zone is None:
         return st.datetimes(min_value, max_value)
 
-    time_zone_info = string_to_zoneinfo(time_zone)
+    time_zone_info = ZoneInfo(time_zone)
 
     # Make sure time zone offsets do not cause out-of-bound datetimes
     if time_unit == "ns":

py-polars/pyproject.toml

@@ -70,7 +70,7 @@ cloudpickle = ["cloudpickle"]
 graph = ["matplotlib"]
 plot = ["altair >= 5.4.0"]
 style = ["great-tables >= 0.8.0"]
-timezone = ["backports.zoneinfo; python_version < '3.9'", "tzdata; platform_system == 'Windows'"]
+timezone = ["tzdata; platform_system == 'Windows'"]
 
 # GPU Engine
 gpu = ["cudf-polars-cu12"]

py-polars/requirements-dev.txt

@@ -23,12 +23,11 @@ pyarrow
 pydantic>=2.0.0
 numba
 # Datetime / time zones
-backports.zoneinfo; python_version < '3.9'
 tzdata; platform_system == 'Windows'
 # Database
 sqlalchemy
-adbc-driver-manager; python_version >= '3.9' and platform_system != 'Windows'
-adbc-driver-sqlite; python_version >= '3.9' and platform_system != 'Windows'
+adbc-driver-manager; platform_system != 'Windows'
+adbc-driver-sqlite; platform_system != 'Windows'
 aiosqlite
 connectorx
 kuzu
@@ -49,7 +48,7 @@ zstandard
 # Plotting
 altair>=5.4.0
 # Styling
-great-tables>=0.8.0; python_version >= '3.9'
+great-tables>=0.8.0
 # Async
 gevent
 # Graph

py-polars/tests/unit/constructors/test_constructors.py

@@ -5,6 +5,7 @@
 from decimal import Decimal
 from random import shuffle
 from typing import TYPE_CHECKING, Any, Literal, NamedTuple
+from zoneinfo import ZoneInfo
 
 import numpy as np
 import pandas as pd
@@ -23,16 +24,13 @@
 if TYPE_CHECKING:
     import sys
     from collections.abc import Callable
-    from zoneinfo import ZoneInfo
 
     from polars._typing import PolarsDataType
 
     if sys.version_info >= (3, 11):
         from typing import Self
     else:
         from typing_extensions import Self
-else:
-    from polars._utils.convert import string_to_zoneinfo as ZoneInfo
 
 
 # -----------------------------------------------------------------------------------

py-polars/tests/unit/dataframe/test_df.py

@@ -8,6 +8,7 @@
 from io import BytesIO
 from operator import floordiv, truediv
 from typing import TYPE_CHECKING, Any, Callable, cast
+from zoneinfo import ZoneInfo
 
 import numpy as np
 import pyarrow as pa
@@ -34,12 +35,9 @@
 
 if TYPE_CHECKING:
     from collections.abc import Iterator, Sequence
-    from zoneinfo import ZoneInfo
 
     from polars import Expr
     from polars._typing import JoinStrategy, UniqueKeepStrategy
-else:
-    from polars._utils.convert import string_to_zoneinfo as ZoneInfo
 
 
 def test_version() -> None:

py-polars/tests/unit/dataframe/test_upsample.py

@@ -2,6 +2,7 @@
 
 from datetime import datetime
 from typing import TYPE_CHECKING
+from zoneinfo import ZoneInfo
 
 import pytest
 
@@ -11,11 +12,8 @@
 
 if TYPE_CHECKING:
     from datetime import timezone
-    from zoneinfo import ZoneInfo
 
     from polars._typing import FillNullStrategy, PolarsIntegerType
-else:
-    from polars._utils.convert import string_to_zoneinfo as ZoneInfo
 
 
 @pytest.mark.parametrize(

py-polars/tests/unit/datatypes/test_temporal.py

@@ -3,6 +3,7 @@
 import io
 from datetime import date, datetime, time, timedelta, timezone
 from typing import TYPE_CHECKING, Any, cast
+from zoneinfo import ZoneInfo
 
 import hypothesis.strategies as st
 import numpy as np
@@ -27,15 +28,11 @@
 from tests.unit.conftest import DATETIME_DTYPES, TEMPORAL_DTYPES
 
 if TYPE_CHECKING:
-    from zoneinfo import ZoneInfo
-
     from polars._typing import (
         Ambiguous,
         PolarsTemporalType,
         TimeUnit,
     )
-else:
-    from polars._utils.convert import string_to_zoneinfo as ZoneInfo
 
 
 def test_fill_null() -> None:

py-polars/tests/unit/expr/test_exprs.py

@@ -3,6 +3,7 @@
 from datetime import date, datetime, timedelta, timezone
 from itertools import permutations
 from typing import TYPE_CHECKING, Any, cast
+from zoneinfo import ZoneInfo
 
 import pytest
 
@@ -18,11 +19,7 @@
 )
 
 if TYPE_CHECKING:
-    from zoneinfo import ZoneInfo
-
     from polars._typing import PolarsDataType
-else:
-    from polars._utils.convert import string_to_zoneinfo as ZoneInfo
 
 
 def test_arg_true() -> None:

py-polars/tests/unit/functions/as_datatype/test_datetime.py

@@ -2,6 +2,7 @@
 
 from datetime import datetime
 from typing import TYPE_CHECKING
+from zoneinfo import ZoneInfo
 
 import pytest
 
@@ -10,11 +11,7 @@
 from polars.testing import assert_series_equal
 
 if TYPE_CHECKING:
-    from zoneinfo import ZoneInfo
-
     from polars._typing import TimeUnit
-else:
-    from polars._utils.convert import string_to_zoneinfo as ZoneInfo
 
 
 def test_date_datetime() -> None:

py-polars/tests/unit/functions/range/test_datetime_range.py

@@ -2,6 +2,7 @@
 
 from datetime import date, datetime, timedelta
 from typing import TYPE_CHECKING
+from zoneinfo import ZoneInfo
 
 import hypothesis.strategies as st
 import pytest
@@ -13,11 +14,7 @@
 from polars.testing import assert_frame_equal, assert_series_equal
 
 if TYPE_CHECKING:
-    from zoneinfo import ZoneInfo
-
     from polars._typing import ClosedInterval, PolarsDataType, TimeUnit
-else:
-    from polars._utils.convert import string_to_zoneinfo as ZoneInfo
 
 
 def test_datetime_range() -> None: