Fix bug roundtripping datetime.time objects after midnight in eastern hemisphere timezones (#2417) (#2438)
* Fix bug roundtripping datetime.time objects after midnight in eastern hemisphere timezones (#2417)
* tests: check more timezones
* Fix review remarks: remove useless comment and skip setting TZ environment variable on Windows
diff --git a/include/pybind11/chrono.h b/include/pybind11/chrono.h
index 6b9ab9b..6127c65 100644
--- a/include/pybind11/chrono.h
+++ b/include/pybind11/chrono.h
@@ -150,21 +150,28 @@
// Lazy initialise the PyDateTime import
if (!PyDateTimeAPI) { PyDateTime_IMPORT; }
- std::time_t tt = system_clock::to_time_t(time_point_cast<system_clock::duration>(src));
+ // Get out microseconds, and make sure they are positive, to avoid bug in eastern hemisphere time zones
+ // (cfr. https://github.com/pybind/pybind11/issues/2417)
+ using us_t = duration<int, std::micro>;
+ auto us = duration_cast<us_t>(src.time_since_epoch() % seconds(1));
+ if (us.count() < 0)
+ us += seconds(1);
+
+ // Subtract microseconds BEFORE `system_clock::to_time_t`, because:
+ // > If std::time_t has lower precision, it is implementation-defined whether the value is rounded or truncated.
+ // (https://en.cppreference.com/w/cpp/chrono/system_clock/to_time_t)
+ std::time_t tt = system_clock::to_time_t(time_point_cast<system_clock::duration>(src - us));
// this function uses static memory so it's best to copy it out asap just in case
// otherwise other code that is using localtime may break this (not just python code)
std::tm localtime = *std::localtime(&tt);
- // Declare these special duration types so the conversions happen with the correct primitive types (int)
- using us_t = duration<int, std::micro>;
-
return PyDateTime_FromDateAndTime(localtime.tm_year + 1900,
localtime.tm_mon + 1,
localtime.tm_mday,
localtime.tm_hour,
localtime.tm_min,
localtime.tm_sec,
- (duration_cast<us_t>(src.time_since_epoch() % seconds(1))).count());
+ us.count());
}
PYBIND11_TYPE_CASTER(type, _("datetime.datetime"));
};
diff --git a/tests/test_chrono.cpp b/tests/test_chrono.cpp
index 899d08d..1d79d4b 100644
--- a/tests/test_chrono.cpp
+++ b/tests/test_chrono.cpp
@@ -10,6 +10,7 @@
#include "pybind11_tests.h"
#include <pybind11/chrono.h>
+#include <chrono>
TEST_SUBMODULE(chrono, m) {
using system_time = std::chrono::system_clock::time_point;
diff --git a/tests/test_chrono.py b/tests/test_chrono.py
index 5392f8f..f94d5ba 100644
--- a/tests/test_chrono.py
+++ b/tests/test_chrono.py
@@ -1,6 +1,9 @@
# -*- coding: utf-8 -*-
from pybind11_tests import chrono as m
import datetime
+import pytest
+
+import env # noqa: F401
def test_chrono_system_clock():
@@ -70,8 +73,30 @@
assert time2.microsecond == 0
-def test_chrono_system_clock_roundtrip_time():
- time1 = datetime.datetime.today().time()
+SKIP_TZ_ENV_ON_WIN = pytest.mark.skipif(
+ "env.WIN", reason="TZ environment variable only supported on POSIX"
+)
+
+
+@pytest.mark.parametrize("time1", [
+ datetime.datetime.today().time(),
+ datetime.time(0, 0, 0),
+ datetime.time(0, 0, 0, 1),
+ datetime.time(0, 28, 45, 109827),
+ datetime.time(0, 59, 59, 999999),
+ datetime.time(1, 0, 0),
+ datetime.time(5, 59, 59, 0),
+ datetime.time(5, 59, 59, 1),
+])
+@pytest.mark.parametrize("tz", [
+ None,
+ pytest.param("Europe/Brussels", marks=SKIP_TZ_ENV_ON_WIN),
+ pytest.param("Asia/Pyongyang", marks=SKIP_TZ_ENV_ON_WIN),
+ pytest.param("America/New_York", marks=SKIP_TZ_ENV_ON_WIN),
+])
+def test_chrono_system_clock_roundtrip_time(time1, tz, monkeypatch):
+ if tz is not None:
+ monkeypatch.setenv("TZ", "/usr/share/zoneinfo/{}".format(tz))
# Roundtrip the time
datetime2 = m.test_chrono2(time1)