[Python-checkins] cpython: remove the ability of datetime.time to be considered false (closes #13936)

Fri Mar 21 00:02:52 CET 2014

http://hg.python.org/cpython/rev/89aa669dcc61
changeset: 89892:89aa669dcc61
user: Benjamin Peterson <benjamin at python.org>
date: Thu Mar 20 18:00:35 2014 -0500
summary:
 remove the ability of datetime.time to be considered false (closes #13936)
files:
 Doc/library/datetime.rst | 11 ++++--
 Doc/whatsnew/3.5.rst | 5 ++-
 Lib/datetime.py | 6 ----
 Lib/test/datetimetester.py | 21 +++----------
 Misc/NEWS | 3 ++
 Modules/_datetimemodule.c | 38 +-------------------------
 6 files changed, 20 insertions(+), 64 deletions(-)

diff --git a/Doc/library/datetime.rst b/Doc/library/datetime.rst
--- a/Doc/library/datetime.rst
+++ b/Doc/library/datetime.rst
@@ -1378,10 +1378,13 @@
 
 * efficient pickling
 
-* in Boolean contexts, a :class:`.time` object is considered to be true if and
- only if, after converting it to minutes and subtracting :meth:`utcoffset` (or
- ``0`` if that's ``None``), the result is non-zero.
-
+In boolean contexts, a :class:`.time` object is always considered to be true.
+
+.. versionchanged:: 3.5
+ Before Python 3.5, a :class:`.time` object was considered to be false if it
+ represented midnight in UTC. This behavior was considered obscure and
+ error-prone and has been removed in Python 3.5. See :issue:`13936` for full
+ details.
 
 Instance methods:
 
diff --git a/Doc/whatsnew/3.5.rst b/Doc/whatsnew/3.5.rst
--- a/Doc/whatsnew/3.5.rst
+++ b/Doc/whatsnew/3.5.rst
@@ -186,4 +186,7 @@
 This section lists previously described changes and other bugfixes
 that may require changes to your code.
 
-* Nothing yet.
+* Before Python 3.5, a :class:`datetime.time` object was considered to be false
+ if it represented midnight in UTC. This behavior was considered obscure and
+ error-prone and has been removed in Python 3.5. See :issue:`13936` for full
+ details.
diff --git a/Lib/datetime.py b/Lib/datetime.py
--- a/Lib/datetime.py
+++ b/Lib/datetime.py
@@ -1249,12 +1249,6 @@
 _check_tzinfo_arg(tzinfo)
 return time(hour, minute, second, microsecond, tzinfo)
 
- def __bool__(self):
- if self.second or self.microsecond:
- return True
- offset = self.utcoffset() or timedelta(0)
- return timedelta(hours=self.hour, minutes=self.minute) != offset
-
 # Pickle support.
 
 def _getstate(self):
diff --git a/Lib/test/datetimetester.py b/Lib/test/datetimetester.py
--- a/Lib/test/datetimetester.py
+++ b/Lib/test/datetimetester.py
@@ -2270,13 +2270,14 @@
 self.assertEqual(orig, derived)
 
 def test_bool(self):
+ # time is always True.
 cls = self.theclass
 self.assertTrue(cls(1))
 self.assertTrue(cls(0, 1))
 self.assertTrue(cls(0, 0, 1))
 self.assertTrue(cls(0, 0, 0, 1))
- self.assertFalse(cls(0))
- self.assertFalse(cls())
+ self.assertTrue(cls(0))
+ self.assertTrue(cls())
 
 def test_replace(self):
 cls = self.theclass
@@ -2629,7 +2630,7 @@
 self.assertEqual(derived.tzname(), 'cookie')
 
 def test_more_bool(self):
- # Test cases with non-None tzinfo.
+ # time is always True.
 cls = self.theclass
 
 t = cls(0, tzinfo=FixedOffset(-300, ""))
@@ -2639,23 +2640,11 @@
 self.assertTrue(t)
 
 t = cls(5, tzinfo=FixedOffset(300, ""))
- self.assertFalse(t)
+ self.assertTrue(t)
 
 t = cls(23, 59, tzinfo=FixedOffset(23*60 + 59, ""))
- self.assertFalse(t)
-
- # Mostly ensuring this doesn't overflow internally.
- t = cls(0, tzinfo=FixedOffset(23*60 + 59, ""))
 self.assertTrue(t)
 
- # But this should yield a value error -- the utcoffset is bogus.
- t = cls(0, tzinfo=FixedOffset(24*60, ""))
- self.assertRaises(ValueError, lambda: bool(t))
-
- # Likewise.
- t = cls(0, tzinfo=FixedOffset(-24*60, ""))
- self.assertRaises(ValueError, lambda: bool(t))
-
 def test_replace(self):
 cls = self.theclass
 z100 = FixedOffset(100, "+100")
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -23,6 +23,9 @@
 Library
 -------
 
+- Issue #13936: Remove the ability of datetime.time instances to be considered
+ false in boolean contexts.
+
 - Issue 18931: selectors module now supports /dev/poll on Solaris.
 Patch by Giampaolo Rodola'.
 
diff --git a/Modules/_datetimemodule.c b/Modules/_datetimemodule.c
--- a/Modules/_datetimemodule.c
+++ b/Modules/_datetimemodule.c
@@ -3805,29 +3805,6 @@
 return clone;
 }
 
-static int
-time_bool(PyObject *self)
-{
- PyObject *offset, *tzinfo;
- int offsecs = 0;
-
- if (TIME_GET_SECOND(self) || TIME_GET_MICROSECOND(self)) {
- /* Since utcoffset is in whole minutes, nothing can
- * alter the conclusion that this is nonzero.
- */
- return 1;
- }
- tzinfo = GET_TIME_TZINFO(self);
- if (tzinfo != Py_None) {
- offset = call_utcoffset(tzinfo, Py_None);
- if (offset == NULL)
- return -1;
- offsecs = GET_TD_DAYS(offset)*86400 + GET_TD_SECONDS(offset);
- Py_DECREF(offset);
- }
- return (TIME_GET_MINUTE(self)*60 - offsecs + TIME_GET_HOUR(self)*3600) != 0;
-}
-
 /* Pickle support, a simple use of __reduce__. */
 
 /* Let basestate be the non-tzinfo data string.
@@ -3895,19 +3872,6 @@
 All arguments are optional. tzinfo may be None, or an instance of\n\
 a tzinfo subclass. The remaining arguments may be ints.\n");
 
-static PyNumberMethods time_as_number = {
- 0, /* nb_add */
- 0, /* nb_subtract */
- 0, /* nb_multiply */
- 0, /* nb_remainder */
- 0, /* nb_divmod */
- 0, /* nb_power */
- 0, /* nb_negative */
- 0, /* nb_positive */
- 0, /* nb_absolute */
- (inquiry)time_bool, /* nb_bool */
-};
-
 static PyTypeObject PyDateTime_TimeType = {
 PyVarObject_HEAD_INIT(NULL, 0)
 "datetime.time", /* tp_name */
@@ -3919,7 +3883,7 @@
 0, /* tp_setattr */
 0, /* tp_reserved */
 (reprfunc)time_repr, /* tp_repr */
- &time_as_number, /* tp_as_number */
+ 0, /* tp_as_number */
 0, /* tp_as_sequence */
 0, /* tp_as_mapping */
 (hashfunc)time_hash, /* tp_hash */
-- 
Repository URL: http://hg.python.org/cpython
