Migrate from pytz to zoneinfo

Migrates code base and tests from `pytz` to `zoneinfo`.

etc/bench.py

@@ -1,9 +1,9 @@
 import itertools
 
 import pandas as pd
-from pytz import UTC
 
 from exchange_calendars import get_calendar
+from exchange_calendars.calendar_helpers import UTC
 from exchange_calendars.calendar_utils import (
     ExchangeCalendarDispatcher,
     _default_calendar_aliases,

etc/check_holidays.py

@@ -4,6 +4,7 @@
 import pandas as pd
 
 from exchange_calendars import get_calendar
+from exchange_calendars.calendar_helpers import UTC
 from exchange_calendars.calendar_utils import default_calendar_names
 
 
@@ -136,7 +137,7 @@ def _check_range(start, end, holidays, cal, calendar_name):
 @click.option(
     "--min-date",
     default=pd.Timestamp("2002-01-01"),
-    type=TimestampType(tz="UTC"),
+    type=TimestampType(tz=UTC),
     help="Start the holiday comparison at this date.",
     show_default=True,
 )
@@ -190,7 +191,6 @@ def main(
     strip_x_from_cal_name,
     answer_key_calendar_name,
 ):
-
     check_holidays(
         holiday_key_path,
         calendar_column,

etc/factory_bounds.py

@@ -10,15 +10,17 @@
 """
 
 from __future__ import annotations
-import dataclasses
+
 import abc
+import dataclasses
 import pathlib
 import pickle
 from typing import Literal, Type
 
 import pandas as pd
 
 import exchange_calendars as xcals
+from exchange_calendars.calendar_helpers import UTC
 
 
 @dataclasses.dataclass
@@ -72,7 +74,7 @@ def calendar_name(self) -> str:
 
     @property
     def today(self) -> pd.Timestamp:
-        return pd.Timestamp.now(tz="UTC").floor("D")
+        return pd.Timestamp.now(tz=UTC).floor("D")
 
     def _get_calendar(
         self,
@@ -173,13 +175,13 @@ def _try_short_cut(
         """
         if bound == "start":
             likely_bounds = [
-                pd.Timestamp("1678-01-01", tz="UTC"),
-                pd.Timestamp("1679-01-01", tz="UTC"),
+                pd.Timestamp("1678-01-01", tz=UTC),
+                pd.Timestamp("1679-01-01", tz=UTC),
             ]
         else:
             likely_bounds = [
-                pd.Timestamp("2260-12-31", tz="UTC"),
-                pd.Timestamp("2262-04-10", tz="UTC"),
+                pd.Timestamp("2260-12-31", tz=UTC),
+                pd.Timestamp("2262-04-10", tz=UTC),
             ]
 
         for likely_bound in likely_bounds:
@@ -191,9 +193,9 @@ def _try_short_cut(
     @staticmethod
     def _initial_value(bound: Literal["start", "end"]) -> pd.Timestamp:
         if bound == "start":
-            return pd.Timestamp.min.ceil("D").tz_localize("UTC")
+            return pd.Timestamp.min.ceil("D").tz_localize(UTC)
         else:
-            return pd.Timestamp.max.floor("D").tz_localize("UTC")
+            return pd.Timestamp.max.floor("D").tz_localize(UTC)
 
     def _get_bound(
         self, bound: Literal["start", "end"]

etc/lunisolar

@@ -30,6 +30,8 @@ import pandas as pd
 import toolz
 from novas.compat import eph_manager
 
+from exchange_calendars.calendar_helpers import UTC
+
 
 @contextlib.contextmanager
 def ephemeris():
@@ -1089,7 +1091,7 @@ def utc_to_chinese_date(arr):
         An array of datetime64[ns] at midnight corresponding the date in China
         of the input.
     """
-    ts = pd.to_datetime(arr).tz_localize("UTC").tz_convert("Asia/Shanghai")
+    ts = pd.to_datetime(arr).tz_localize(UTC).tz_convert("Asia/Shanghai")
     out = ts.normalize().tz_localize(None)
     if isinstance(out, pd.Timestamp):
         return out.asm8

exchange_calendars/always_open.py

@@ -1,8 +1,7 @@
 from datetime import time
 
-from pytz import UTC
-
 from .exchange_calendar import ExchangeCalendar
+from exchange_calendars.calendar_helpers import UTC
 
 
 class AlwaysOpenCalendar(ExchangeCalendar):

exchange_calendars/calendar_helpers.py

@@ -4,16 +4,18 @@
 import datetime
 import typing
 from typing import Literal
+from zoneinfo import ZoneInfo
 
 import numpy as np
 import pandas as pd
-import pytz
 
 from exchange_calendars import errors
 
 if typing.TYPE_CHECKING:
     from exchange_calendars import ExchangeCalendar
 
+UTC = ZoneInfo("UTC")
+
 NANOSECONDS_PER_MINUTE = int(6e10)
 
 NP_NAT = pd.NaT.value
@@ -36,7 +38,6 @@
 
 
 def next_divider_idx(dividers: np.ndarray, minute_val: int) -> int:
-
     divider_idx = np.searchsorted(dividers, minute_val, side="right")
     target = dividers[divider_idx]
 
@@ -48,7 +49,6 @@ def next_divider_idx(dividers: np.ndarray, minute_val: int) -> int:
 
 
 def previous_divider_idx(dividers: np.ndarray, minute_val: int) -> int:
-
     divider_idx = np.searchsorted(dividers, minute_val)
 
     if divider_idx == 0:
@@ -146,9 +146,9 @@ def to_utc(ts: pd.Timestamp) -> pd.Timestamp:
         Timestamp to return a copy of with timezone set to UTC.
     """
     try:
-        return ts.tz_convert(pytz.UTC)
+        return ts.tz_convert(UTC)
     except TypeError:
-        return ts.tz_localize(pytz.UTC)
+        return ts.tz_localize(UTC)
 
 
 def parse_timestamp(
@@ -189,9 +189,9 @@ def parse_timestamp(
         to minute resolution.
 
     utc : default: True
-        True - convert / set timezone to "UTC".
+        True - convert / set timezone to UTC.
         False - leave any timezone unchanged. Note, if timezone of
-        `timestamp` is "UTC" then will remain as "UTC".
+        `timestamp` is UTC then will remain as UTC.
 
     Raises
     ------
@@ -224,8 +224,8 @@ def parse_timestamp(
             else:
                 raise ValueError(msg) from e
 
-    if utc and ts.tz is not pytz.UTC:
-        ts = ts.tz_localize("UTC") if ts.tz is None else ts.tz_convert("UTC")
+    if utc and ts.tz is not UTC:
+        ts = ts.tz_localize(UTC) if ts.tz is None else ts.tz_convert(UTC)
 
     if ts.second or ts.microsecond or ts.nanosecond:
         if side is None and calendar is None:
@@ -376,7 +376,7 @@ def parse_date(
 
     if ts.tz is not None:
         raise ValueError(
-            f"Parameter `{param_name}` received with timezone defined as '{ts.tz.zone}'"
+            f"Parameter `{param_name}` received with timezone defined as '{ts.tz.key}'"
             f" although a Date must be timezone naive."
         )
 
@@ -630,7 +630,6 @@ def _trading_index(self) -> np.ndarray:
         becoming unsynced with the corresponding left indices.
         """
         if self.has_break:
-
             # sessions with breaks
             index_am = self._create_index_for_sessions(
                 self.opens[self.mask],
@@ -680,7 +679,7 @@ def trading_index(self) -> pd.DatetimeIndex:
         index = self._trading_index()
         if self.has_break:
             index.sort()
-        index = pd.DatetimeIndex(index, tz=pytz.UTC)
+        index = pd.DatetimeIndex(index, tz=UTC)
         return self.curtail_for_times(index)
 
     @contextlib.contextmanager
@@ -718,7 +717,7 @@ def trading_index_intervals(self) -> pd.IntervalIndex:
             else:
                 raise errors.IntervalsOverlapError()
 
-        left = pd.DatetimeIndex(left, tz=pytz.UTC)
-        right = pd.DatetimeIndex(right, tz=pytz.UTC)
+        left = pd.DatetimeIndex(left, tz=UTC)
+        right = pd.DatetimeIndex(right, tz=UTC)
         index = pd.IntervalIndex.from_arrays(left, right, self.closed)
         return self.curtail_for_times(index)

exchange_calendars/exchange_calendar.py

@@ -22,17 +22,17 @@
 import operator
 from typing import TYPE_CHECKING, Literal, Any
 import warnings
+from zoneinfo import ZoneInfo
 
 import numpy as np
 import pandas as pd
 import toolz
 from pandas.tseries.holiday import AbstractHolidayCalendar
 from pandas.tseries.offsets import CustomBusinessDay
-import pytz
-from pytz import UTC
 
 from exchange_calendars import errors
 from .calendar_helpers import (
+    UTC,
     NANOSECONDS_PER_MINUTE,
     NP_NAT,
     Date,
@@ -55,6 +55,7 @@
 if TYPE_CHECKING:
     from pandas._libs.tslibs.nattype import NaTType
 
+
 GLOBAL_DEFAULT_START = pd.Timestamp.now().floor("D") - pd.DateOffset(years=20)
 # Give an aggressive buffer for logic that needs to use the next trading
 # day or minute.
@@ -84,7 +85,7 @@ def selection(
 def _group_times(
     sessions: pd.DatetimeIndex,
     times: None | Sequence[tuple[pd.Timestamp | None, datetime.time]],
-    tz: pytz.tzinfo.BaseTzInfo,
+    tz: ZoneInfo,
     offset: int = 0,
 ) -> pd.DatetimeIndex | None:
     """Evaluate standard times for a specific session bound.
@@ -424,7 +425,7 @@ def _bound_max_error_msg(self, end: pd.Timestamp) -> str:
 
     @property
     @abstractmethod
-    def tz(self) -> pytz.tzinfo.BaseTzInfo:
+    def tz(self) -> ZoneInfo:
         """Calendar timezone."""
         raise NotImplementedError()
 
@@ -1475,8 +1476,8 @@ def is_open_at_time(
                 f" got type {type(ts)}."
             )
 
-        if ts.tz is not pytz.UTC:
-            ts = ts.tz_localize("UTC") if ts.tz is None else ts.tz_convert("UTC")
+        if ts.tz is not UTC:
+            ts = ts.tz_localize(UTC) if ts.tz is None else ts.tz_convert(UTC)
 
         if self._minute_oob(ts):
             raise errors.MinuteOutOfBounds(self, ts, "timestamp")
@@ -2820,7 +2821,7 @@ def scheduled_special_times(
     start: pd.Timestamp,
     end: pd.Timestamp,
     time: datetime.time,
-    tz: pytz.tzinfo.BaseTzInfo,
+    tz: ZoneInfo,
 ) -> pd.Series:
     """Return map of dates to special times.
 

exchange_calendars/exchange_calendar_aixk.py

@@ -1,5 +1,6 @@
 from datetime import time
 from itertools import chain
+from zoneinfo import ZoneInfo
 
 import pandas as pd
 from pandas.tseries.holiday import (
@@ -8,7 +9,6 @@
     nearest_workday,
     next_workday,
 )
-import pytz
 
 from .common_holidays import new_years_day, eid_al_adha_first_day
 from .exchange_calendar import (
@@ -172,7 +172,7 @@ class AIXKExchangeCalendar(ExchangeCalendar):
 
     name = "AIXK"
 
-    tz = pytz.timezone("Asia/Almaty")
+    tz = ZoneInfo("Asia/Almaty")
 
     open_times = ((None, time(11)),)
 

exchange_calendars/exchange_calendar_asex.py

@@ -15,10 +15,10 @@
 
 from datetime import time, timedelta
 from itertools import chain
+from zoneinfo import ZoneInfo
 
 import pandas as pd
 from pandas.tseries.holiday import EasterMonday, GoodFriday, Holiday
-from pytz import timezone
 
 from .common_holidays import (
     assumption_day,
@@ -102,7 +102,7 @@ class ASEXExchangeCalendar(ExchangeCalendar):
 
     name = "ASEX"
 
-    tz = timezone("Europe/Athens")
+    tz = ZoneInfo("Europe/Athens")
 
     open_times = ((None, time(10)),)
 

exchange_calendars/exchange_calendar_bvmf.py

@@ -14,6 +14,7 @@
 # limitations under the License.
 
 from datetime import time
+from zoneinfo import ZoneInfo
 
 import pandas as pd
 from pandas.tseries.holiday import (
@@ -23,7 +24,6 @@
     Holiday,
     previous_friday,
 )
-from pytz import timezone
 
 from .common_holidays import corpus_christi
 from .exchange_calendar import HolidayCalendar, ExchangeCalendar
@@ -174,7 +174,7 @@ class BVMFExchangeCalendar(ExchangeCalendar):
 
     name = "BVMF"
 
-    tz = timezone("America/Sao_Paulo")
+    tz = ZoneInfo("America/Sao_Paulo")
 
     regular_late_open = time(13)
 

exchange_calendars/exchange_calendar_cmes.py

@@ -14,14 +14,14 @@
 # limitations under the License.
 
 from datetime import time
+from zoneinfo import ZoneInfo
 
 from pandas.tseries.holiday import (
     GoodFriday,
     USLaborDay,
     USPresidentsDay,
     USThanksgivingDay,
 )
-from pytz import timezone
 
 from .exchange_calendar import HolidayCalendar, ExchangeCalendar
 from .us_holidays import (
@@ -55,7 +55,7 @@ class CMESExchangeCalendar(ExchangeCalendar):
 
     name = "CMES"
 
-    tz = timezone("America/Chicago")
+    tz = ZoneInfo("America/Chicago")
 
     open_times = ((None, time(17)),)