diff options
| -rw-r--r-- | Lib/datetime.py | 6 | ||||
| -rw-r--r-- | Lib/test/datetimetester.py | 6 | ||||
| -rw-r--r-- | Modules/_datetimemodule.c | 15 |
3 files changed, 19 insertions, 8 deletions
diff --git a/Lib/datetime.py b/Lib/datetime.py index 47e54ec2359..1ae7cb5305a 100644 --- a/Lib/datetime.py +++ b/Lib/datetime.py @@ -485,7 +485,11 @@ class timedelta: def __sub__(self, other): if isinstance(other, timedelta): - return self + -other + # for CPython compatibility, we cannot use + # our __class__ here, but need a real timedelta + return timedelta(self._days - other._days, + self._seconds - other._seconds, + self._microseconds - other._microseconds) return NotImplemented def __rsub__(self, other): diff --git a/Lib/test/datetimetester.py b/Lib/test/datetimetester.py index e9ceee6d961..38f3b8f19bd 100644 --- a/Lib/test/datetimetester.py +++ b/Lib/test/datetimetester.py @@ -383,6 +383,12 @@ class TestTimeDelta(HarmlessMixedComparison, unittest.TestCase): for i in range(-10, 10): eq((i*us/-3)//us, round(i/-3)) + # Issue #11576 + eq(td(999999999, 86399, 999999) - td(999999999, 86399, 999998), + td(0, 0, 1)) + eq(td(999999999, 1, 1) - td(999999999, 1, 0), + td(0, 0, 1)) + def test_disallowed_computations(self): a = timedelta(42) diff --git a/Modules/_datetimemodule.c b/Modules/_datetimemodule.c index f50cae0bd84..a19c0c355be 100644 --- a/Modules/_datetimemodule.c +++ b/Modules/_datetimemodule.c @@ -1801,13 +1801,14 @@ delta_subtract(PyObject *left, PyObject *right) if (PyDelta_Check(left) && PyDelta_Check(right)) { /* delta - delta */ - PyObject *minus_right = PyNumber_Negative(right); - if (minus_right) { - result = delta_add(left, minus_right); - Py_DECREF(minus_right); - } - else - result = NULL; + /* The C-level additions can't overflow because of the + * invariant bounds. + */ + int days = GET_TD_DAYS(left) - GET_TD_DAYS(right); + int seconds = GET_TD_SECONDS(left) - GET_TD_SECONDS(right); + int microseconds = GET_TD_MICROSECONDS(left) - + GET_TD_MICROSECONDS(right); + result = new_delta(days, seconds, microseconds, 1); } if (result == Py_NotImplemented) |