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DEPR: parsing to tzlocal #50949

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Merged
merged 6 commits into from
Feb 1, 2023
Merged

DEPR: parsing to tzlocal #50949

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c0b99cc
DEPR: parsing to tzlocal
jbrockmendel Jan 24, 2023
dfef22c
skip on windows
jbrockmendel Jan 24, 2023
0bd83b4
ignore warning specific to systems in utc
jbrockmendel Jan 25, 2023
a5aae34
troubleshoot warning
jbrockmendel Jan 26, 2023
a8e25de
troubleshoot
jbrockmendel Jan 26, 2023
3bdb6e5
update warning
jbrockmendel Jan 27, 2023
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1 change: 1 addition & 0 deletions doc/source/whatsnew/v2.0.0.rst
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Expand Up @@ -611,6 +611,7 @@ Other API changes

Deprecations
~~~~~~~~~~~~
- Deprecated parsing datetime strings with system-local timezone to ``tzlocal``, pass a ``tz`` keyword or explicitly call ``tz_localize`` instead (:issue:`50791`)
- Deprecated argument ``infer_datetime_format`` in :func:`to_datetime` and :func:`read_csv`, as a strict version of it is now the default (:issue:`48621`)
- Deprecated :func:`pandas.io.sql.execute` (:issue:`50185`)
- :meth:`Index.is_boolean` has been deprecated. Use :func:`pandas.api.types.is_bool_dtype` instead (:issue:`50042`)
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8 changes: 8 additions & 0 deletions pandas/_libs/tslibs/parsing.pyx
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Expand Up @@ -653,6 +653,14 @@ cdef dateutil_parse(
ret = ret + relativedelta.relativedelta(weekday=res.weekday)
if not ignoretz:
if res.tzname and res.tzname in time.tzname:
# GH#50791
warnings.warn(
"Parsing '{res.tzname}' as tzlocal (dependent on system timezone) "
"is deprecated and will raise in a future version. Pass the 'tz' "
"keyword or call tz_localize after construction instead",
FutureWarning,
stacklevel=find_stack_level()
)
ret = ret.replace(tzinfo=_dateutil_tzlocal())
elif res.tzoffset == 0:
ret = ret.replace(tzinfo=_dateutil_tzutc())
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1 change: 1 addition & 0 deletions pandas/tests/tslibs/test_array_to_datetime.py
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Expand Up @@ -67,6 +67,7 @@ def test_parsing_timezone_offsets(dt_string, expected_tz):
assert result_tz == timezone(timedelta(minutes=expected_tz))


@pytest.mark.filterwarnings("ignore:.*dependent on system timezone.*:FutureWarning")
def test_parsing_non_iso_timezone_offset():
dt_string = "01-01-2013T00:00:00.000000000+0000"
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Shouldn't a UTC offset like this be okay?

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not sure why but this triggered the tzlocal warning on one the builds. best guess is that build had the system timezone set to gmt

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Hmm I thought the spirit of the original deprecation is to forbid the 3 letter abbreviated timezones?

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the spirit is to not give results that depend on your system timezone. so if there is a system-config that results in getting tzlocal in this case, that user will in the future get the same non-tzlocal tzinfo that everyone else gets. i.e. this is not going to start raising for anybody.

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Okay that makes sense. I am just concerned about the seemingly false positive for this test case

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Agreed. im open to suggestions on how to avoid it

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Looks like many CI runs have time.tzname == ("UTC", "UTC"), end up getting tzlocal instead of a tzutc(). Updated to avoid warning in that case.

arr = np.array([dt_string], dtype=object)
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18 changes: 18 additions & 0 deletions pandas/tests/tslibs/test_parsing.py
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Expand Up @@ -5,6 +5,7 @@
import re

from dateutil.parser import parse as du_parse
from dateutil.tz import tzlocal
import numpy as np
import pytest

Expand All @@ -18,6 +19,23 @@
import pandas._testing as tm


@td.skip_if_windows
def test_parsing_tzlocal_deprecated():
# GH#50791
msg = "Pass the 'tz' keyword or call tz_localize after construction instead"
dtstr = "Jan 15 2004 03:00 EST"

with tm.set_timezone("US/Eastern"):
with tm.assert_produces_warning(FutureWarning, match=msg):
res, _ = parse_datetime_string_with_reso(dtstr)

assert isinstance(res.tzinfo, tzlocal)

with tm.assert_produces_warning(FutureWarning, match=msg):
res = parsing.parse_datetime_string(dtstr)
assert isinstance(res.tzinfo, tzlocal)


def test_parse_datetime_string_with_reso():
(parsed, reso) = parse_datetime_string_with_reso("4Q1984")
(parsed_lower, reso_lower) = parse_datetime_string_with_reso("4q1984")
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