Issue #23517: Fix implementation of the ROUND_HALF_UP rounding mode in
datetime.datetime.fromtimestamp() and datetime.datetime.utcfromtimestamp().
microseconds sign should be kept before rounding.
diff --git a/Lib/datetime.py b/Lib/datetime.py
index 5ba2ddb..3bf9edc 100644
--- a/Lib/datetime.py
+++ b/Lib/datetime.py
@@ -1374,6 +1374,26 @@
return self._tzinfo
@classmethod
+ def _fromtimestamp(cls, t, utc, tz):
+ """Construct a datetime from a POSIX timestamp (like time.time()).
+
+ A timezone info object may be passed in as well.
+ """
+ frac, t = _math.modf(t)
+ us = _round_half_up(frac * 1e6)
+ if us >= 1000000:
+ t += 1
+ us -= 1000000
+ elif us < 0:
+ t -= 1
+ us += 1000000
+
+ converter = _time.gmtime if utc else _time.localtime
+ y, m, d, hh, mm, ss, weekday, jday, dst = converter(t)
+ ss = min(ss, 59) # clamp out leap seconds if the platform has them
+ return cls(y, m, d, hh, mm, ss, us, tz)
+
+ @classmethod
def fromtimestamp(cls, t, tz=None):
"""Construct a datetime from a POSIX timestamp (like time.time()).
@@ -1381,21 +1401,7 @@
"""
_check_tzinfo_arg(tz)
- converter = _time.localtime if tz is None else _time.gmtime
-
- t, frac = divmod(t, 1.0)
- us = _round_half_up(frac * 1e6)
-
- # If timestamp is less than one microsecond smaller than a
- # full second, us can be rounded up to 1000000. In this case,
- # roll over to seconds, otherwise, ValueError is raised
- # by the constructor.
- if us == 1000000:
- t += 1
- us = 0
- y, m, d, hh, mm, ss, weekday, jday, dst = converter(t)
- ss = min(ss, 59) # clamp out leap seconds if the platform has them
- result = cls(y, m, d, hh, mm, ss, us, tz)
+ result = cls._fromtimestamp(t, tz is not None, tz)
if tz is not None:
result = tz.fromutc(result)
return result
@@ -1403,19 +1409,7 @@
@classmethod
def utcfromtimestamp(cls, t):
"""Construct a naive UTC datetime from a POSIX timestamp."""
- t, frac = divmod(t, 1.0)
- us = _round_half_up(frac * 1e6)
-
- # If timestamp is less than one microsecond smaller than a
- # full second, us can be rounded up to 1000000. In this case,
- # roll over to seconds, otherwise, ValueError is raised
- # by the constructor.
- if us == 1000000:
- t += 1
- us = 0
- y, m, d, hh, mm, ss, weekday, jday, dst = _time.gmtime(t)
- ss = min(ss, 59) # clamp out leap seconds if the platform has them
- return cls(y, m, d, hh, mm, ss, us)
+ return cls._fromtimestamp(t, True, None)
@classmethod
def now(cls, tz=None):