Skip to content

BUG: Bad shift_forward around UTC+0 when DST #56017

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 8 commits into from
Nov 21, 2023
Merged

BUG: Bad shift_forward around UTC+0 when DST #56017

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
8 commits
Select commit Hold shift + click to select a range
e7d15f0
add tests
quangngd Nov 17, 2023
8c1e35a
fix
quangngd Nov 17, 2023
41d096b
add whatsnew
quangngd Nov 17, 2023
4482dd8
refactor
quangngd Nov 18, 2023
65dbc2b
Revert "refactor"
quangngd Nov 18, 2023
1f89461
fix bug
quangngd Nov 18, 2023
9a6cd66
update
quangngd Nov 21, 2023
6accd91
more cmt
quangngd Nov 21, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 1 addition & 1 deletion doc/source/whatsnew/v2.2.0.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -360,7 +360,7 @@ Timezones
^^^^^^^^^
- Bug in :class:`AbstractHolidayCalendar` where timezone data was not propagated when computing holiday observances (:issue:`54580`)
- Bug in :class:`Timestamp` construction with an ambiguous value and a ``pytz`` timezone failing to raise ``pytz.AmbiguousTimeError`` (:issue:`55657`)
-
- Bug in :meth:`Timestamp.tz_localize` with ``nonexistent="shift_forward`` around UTC+0 during DST (:issue:`51501`)

Numeric
^^^^^^^
Expand Down
9 changes: 7 additions & 2 deletions pandas/_libs/tslibs/tzconversion.pyx
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -416,8 +416,13 @@ timedelta-like}

else:
delta_idx = bisect_right_i8(info.tdata, new_local, info.ntrans)

delta_idx = delta_idx - delta_idx_offset
# Logic similar to the precompute section. But check the current
# delta in case we are moving between UTC+0 and non-zero timezone
if (shift_forward or shift_delta > 0) and \
info.deltas[delta_idx - 1] >= 0:
delta_idx = delta_idx - 1
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Could you write a 1 line comment describing why we need to do this?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

added

else:
delta_idx = delta_idx - delta_idx_offset
result[i] = new_local - info.deltas[delta_idx]
elif fill_nonexist:
result[i] = NPY_NAT
Expand Down
38 changes: 38 additions & 0 deletions pandas/tests/scalar/timestamp/methods/test_tz_localize.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -123,6 +123,44 @@ def test_tz_localize_nonexistent(self, stamp, tz):
ts.tz_localize(tz, nonexistent="raise")
assert ts.tz_localize(tz, nonexistent="NaT") is NaT

@pytest.mark.parametrize(
"stamp, tz, forward_expected, backward_expected",
[
(
"2015-03-29 02:00:00",
"Europe/Warsaw",
"2015-03-29 03:00:00",
"2015-03-29 01:59:59",
), # utc+1 -> utc+2
(
"2023-03-12 02:00:00",
"America/Los_Angeles",
"2023-03-12 03:00:00",
"2023-03-12 01:59:59",
), # utc-8 -> utc-7
(
"2023-03-26 01:00:00",
"Europe/London",
"2023-03-26 02:00:00",
"2023-03-26 00:59:59",
), # utc+0 -> utc+1
(
"2023-03-26 00:00:00",
"Atlantic/Azores",
"2023-03-26 01:00:00",
"2023-03-25 23:59:59",
), # utc-1 -> utc+0
],
)
def test_tz_localize_nonexistent_shift(
self, stamp, tz, forward_expected, backward_expected
):
ts = Timestamp(stamp)
forward_ts = ts.tz_localize(tz, nonexistent="shift_forward")
assert forward_ts == Timestamp(forward_expected, tz=tz)
backward_ts = ts.tz_localize(tz, nonexistent="shift_backward")
assert backward_ts == Timestamp(backward_expected, tz=tz)

def test_tz_localize_ambiguous_raise(self):
# GH#13057
ts = Timestamp("2015-11-1 01:00")
Expand Down