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Merge pull request #29 from jepler/issue24

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Fix handling of naive datetime objects, but deprecate them
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Jeff Epler 2024-07-20 12:49:37 -05:00 committed by GitHub
commit f0dfb35101
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2 changed files with 29 additions and 7 deletions
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29
leapseconddata/__init__.py
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@ -29,6 +29,7 @@ import logging
import pathlib
import re
import urllib.request
import warnings
from dataclasses import dataclass, field
from typing import TYPE_CHECKING, BinaryIO, ClassVar
@ -71,7 +72,7 @@ def _from_ntp_epoch(value: int) -> datetime.datetime:
def datetime_is_tai(when: datetime.datetime) -> bool:
"""Return true if the datetime is in the TAI timescale"""
return when.tzname() == "TAI"
return when.tzinfo is tai
@dataclass(frozen=True)
@ -155,7 +156,10 @@ class LeapSecondData:
@staticmethod
def _utc_datetime(when: datetime.datetime) -> datetime.datetime:
if when.tzinfo is not None and when.tzinfo is not datetime.timezone.utc:
if when.tzinfo is None:
warnings.warn("Use of naive datetime objects is deprecated", DeprecationWarning, stacklevel=2)
when = when.replace(tzinfo=datetime.timezone.utc)
elif when.tzinfo is not datetime.timezone.utc:
when = when.astimezone(datetime.timezone.utc)
return when
@ -194,14 +198,18 @@ class LeapSecondData:
def to_tai(self, when: datetime.datetime, *, check_validity: bool = True) -> datetime.datetime:
"""Convert the given datetime object to TAI.
:param when: Moment in time to convert. If naive, it is assumed to be in UTC.
:param check_validity: Check whether the database is valid for the given moment
A TAI timestamp is returned unchanged.
Naive timestamps are assumed to be UTC. A TAI timestamp is returned unchanged.
A naive timestamp is assumed to be UTC. This behavior is deprecated, and a future
release will raise an exception when ``when`` is naive.
:param when: Moment in time to convert.
:param check_validity: Check whether the database is valid for the given moment
"""
if datetime_is_tai(when):
return when
when = self._utc_datetime(when)
assert when.tzinfo is not None
return (when + self.tai_offset(when, check_validity=check_validity)).replace(tzinfo=tai)
def tai_to_utc(self, when: datetime.datetime, *, check_validity: bool = True) -> datetime.datetime:
@ -209,12 +217,16 @@ class LeapSecondData:
For a leap second, the ``fold`` property of the returned time is True.
:param when: Moment in time to convert. If not naive, its ``tzinfo`` must be `tai`.
A naive timestamp is assumed to be TAI. This behavior is deprecated, and a future
release will raise an exception when ``when`` is naive.
:param when: Moment in time to convert. Its ``tzinfo`` must be `tai`.
:param check_validity: Check whether the database is valid for the given moment
"""
if when.tzinfo is not None and when.tzinfo is not tai:
raise ValueError("Input timestamp is not TAI or naive")
if when.tzinfo is None:
warnings.warn("Use of naive datetime objects is deprecated", DeprecationWarning, stacklevel=1)
when = when.replace(tzinfo=tai)
result = (when - self.tai_offset(when, check_validity=check_validity)).replace(tzinfo=datetime.timezone.utc)
if self.is_leap_second(when, check_validity=check_validity):
@ -224,7 +236,10 @@ class LeapSecondData:
def is_leap_second(self, when: datetime.datetime, *, check_validity: bool = True) -> bool:
"""Return True if the given timestamp is the leap second.
:param when: Moment in time to check. If naive, it is assumed to be in UTC.
A naive timestamp is assumed to be UTC. This behavior is deprecated, and a future
release will raise an exception when ``when`` is naive.
:param when: Moment in time to check.
:param check_validity: Check whether the database is valid for the given moment
For a TAI timestamp, it returns True for the leap second (the one that

7
testleapseconddata.py
View file

@ -136,6 +136,13 @@ class LeapSecondDataTest(unittest.TestCase):
assert when_tai.tzinfo is leapseconddata.tai
assert when_tai2.tzinfo is leapseconddata.tai
def test_to_tai_naive(self) -> None:
when = datetime.datetime(1999, 1, 1, tzinfo=None) - datetime.timedelta(seconds=1) # noqa: DTZ001
when_tai = db.to_tai(when)
when2 = datetime.datetime(1999, 1, 1, tzinfo=datetime.timezone.utc) - datetime.timedelta(seconds=1)
when_tai2 = db.to_tai(when2)
self.assertEqual(when_tai, when_tai2)
def assertPrints(self, code: str, expected: str) -> None: # noqa: N802
buf = io.StringIO()
with contextlib.redirect_stdout(buf):