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BUG: Fix date_range overflow (pandas-dev#23345)
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jbrockmendel authored and tm9k1 committed Nov 19, 2018
1 parent 6429f72 commit 6a10727
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Showing 3 changed files with 48 additions and 2 deletions.
1 change: 1 addition & 0 deletions doc/source/whatsnew/v0.24.0.txt
Original file line number Diff line number Diff line change
Expand Up @@ -1028,6 +1028,7 @@ Datetimelike
- Bug in :class:`PeriodIndex` where adding or subtracting a :class:`timedelta` or :class:`Tick` object produced incorrect results (:issue:`22988`)
- Bug in :func:`date_range` when decrementing a start date to a past end date by a negative frequency (:issue:`23270`)
- Bug in :func:`DataFrame.combine` with datetimelike values raising a TypeError (:issue:`23079`)
- Bug in :func:`date_range` with frequency of ``Day`` or higher where dates sufficiently far in the future could wrap around to the past instead of raising ``OutOfBoundsDatetime`` (:issue:`14187`)

Timedelta
^^^^^^^^^
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42 changes: 40 additions & 2 deletions pandas/core/arrays/datetimes.py
Original file line number Diff line number Diff line change
Expand Up @@ -1355,11 +1355,11 @@ def _generate_regular_range(cls, start, end, periods, freq):
tz = start.tz
elif start is not None:
b = Timestamp(start).value
e = b + np.int64(periods) * stride
e = _generate_range_overflow_safe(b, periods, stride, side='start')
tz = start.tz
elif end is not None:
e = Timestamp(end).value + stride
b = e - np.int64(periods) * stride
b = _generate_range_overflow_safe(e, periods, stride, side='end')
tz = end.tz
else:
raise ValueError("at least 'start' or 'end' should be specified "
Expand All @@ -1384,6 +1384,44 @@ def _generate_regular_range(cls, start, end, periods, freq):
return data


def _generate_range_overflow_safe(endpoint, periods, stride, side='start'):
"""
Calculate the second endpoint for passing to np.arange, checking
to avoid an integer overflow. Catch OverflowError and re-raise
as OutOfBoundsDatetime.
Parameters
----------
endpoint : int
periods : int
stride : int
side : {'start', 'end'}
Returns
-------
other_end : int
Raises
------
OutOfBoundsDatetime
"""
# GH#14187 raise instead of incorrectly wrapping around
assert side in ['start', 'end']
if side == 'end':
stride *= -1

try:
other_end = checked_add_with_arr(np.int64(endpoint),
np.int64(periods) * stride)
except OverflowError:
raise tslib.OutOfBoundsDatetime('Cannot generate range with '
'{side}={endpoint} and '
'periods={periods}'
.format(side=side, endpoint=endpoint,
periods=periods))
return other_end


def _infer_tz_from_endpoints(start, end, tz):
"""
If a timezone is not explicitly given via `tz`, see if one can
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7 changes: 7 additions & 0 deletions pandas/tests/indexes/datetimes/test_date_range.py
Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,7 @@
from pandas import (
DatetimeIndex, Timestamp, bdate_range, compat, date_range, offsets
)
from pandas.errors import OutOfBoundsDatetime
from pandas.tests.series.common import TestData
from pandas.tseries.offsets import (
BDay, CDay, DateOffset, MonthEnd, generate_range, prefix_mapping
Expand Down Expand Up @@ -79,6 +80,12 @@ def test_date_range_timestamp_equiv_preserve_frequency(self):


class TestDateRanges(TestData):
def test_date_range_out_of_bounds(self):
# GH#14187
with pytest.raises(OutOfBoundsDatetime):
date_range('2016-01-01', periods=100000, freq='D')
with pytest.raises(OutOfBoundsDatetime):
date_range(end='1763-10-12', periods=100000, freq='D')

def test_date_range_gen_error(self):
rng = date_range('1/1/2000 00:00', '1/1/2000 00:18', freq='5min')
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