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Issue #28019: itertools.count() no longer rounds non-integer step in range 

between 1.0 and 2.0 to 1.
This commit is contained in:
Serhiy Storchaka 2016-09-10 09:49:24 +03:00
parent e617521b0d
commit 8ddcf3abf7
3 changed files with 55 additions and 21 deletions
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28
Lib/test/test_itertools.py
View File

@ -511,12 +511,18 @@ class TestBasicOps(unittest.TestCase):
self.assertEqual(take(2, zip('abc',count(-3))), [('a', -3), ('b', -2)])
self.assertRaises(TypeError, count, 2, 3, 4)
self.assertRaises(TypeError, count, 'a')
self.assertEqual(list(islice(count(maxsize-5), 10)),
self.assertEqual(take(10, count(maxsize-5)),
list(range(maxsize-5, maxsize+5)))
self.assertEqual(list(islice(count(-maxsize-5), 10)),
self.assertEqual(take(10, count(-maxsize-5)),
list(range(-maxsize-5, -maxsize+5)))
self.assertEqual(list(islice(count(10, maxsize+5), 3)),
list(range(10, 10+3*(maxsize+5), maxsize+5)))
self.assertEqual(take(3, count(3.25)), [3.25, 4.25, 5.25])
self.assertEqual(take(3, count(3.25-4j)), [3.25-4j, 4.25-4j, 5.25-4j])
self.assertEqual(take(3, count(Decimal('1.1'))),
[Decimal('1.1'), Decimal('2.1'), Decimal('3.1')])
self.assertEqual(take(3, count(Fraction(2, 3))),
[Fraction(2, 3), Fraction(5, 3), Fraction(8, 3)])
BIGINT = 1<<1000
self.assertEqual(take(3, count(BIGINT)), [BIGINT, BIGINT+1, BIGINT+2])
c = count(3)
self.assertEqual(repr(c), 'count(3)')
next(c)
@ -524,8 +530,10 @@ class TestBasicOps(unittest.TestCase):
c = count(-9)
self.assertEqual(repr(c), 'count(-9)')
next(c)
self.assertEqual(repr(count(10.25)), 'count(10.25)')
self.assertEqual(next(c), -8)
self.assertEqual(repr(count(10.25)), 'count(10.25)')
self.assertEqual(repr(count(10.0)), 'count(10.0)')
self.assertEqual(type(next(count(10.0))), float)
for i in (-sys.maxsize-5, -sys.maxsize+5 ,-10, -1, 0, 10, sys.maxsize-5, sys.maxsize+5):
# Test repr
r1 = repr(count(i))
@ -549,16 +557,22 @@ class TestBasicOps(unittest.TestCase):
[('a', 2), ('b', 5), ('c', 8)])
self.assertEqual(lzip('abc',count(step=-1)),
[('a', 0), ('b', -1), ('c', -2)])
self.assertRaises(TypeError, count, 'a', 'b')
self.assertEqual(lzip('abc',count(2,0)), [('a', 2), ('b', 2), ('c', 2)])
self.assertEqual(lzip('abc',count(2,1)), [('a', 2), ('b', 3), ('c', 4)])
self.assertEqual(lzip('abc',count(2,3)), [('a', 2), ('b', 5), ('c', 8)])
self.assertEqual(take(20, count(maxsize-15, 3)), take(20, range(maxsize-15, maxsize+100, 3)))
self.assertEqual(take(20, count(-maxsize-15, 3)), take(20, range(-maxsize-15,-maxsize+100, 3)))
self.assertEqual(take(3, count(10, maxsize+5)),
list(range(10, 10+3*(maxsize+5), maxsize+5)))
self.assertEqual(take(3, count(2, 1.25)), [2, 3.25, 4.5])
self.assertEqual(take(3, count(2, 3.25-4j)), [2, 5.25-4j, 8.5-8j])
self.assertEqual(take(3, count(Decimal('1.1'), Decimal('.1'))),
[Decimal('1.1'), Decimal('1.2'), Decimal('1.3')])
self.assertEqual(take(3, count(Fraction(2,3), Fraction(1,7))),
[Fraction(2,3), Fraction(17,21), Fraction(20,21)])
BIGINT = 1<<1000
self.assertEqual(take(3, count(step=BIGINT)), [0, BIGINT, 2*BIGINT])
self.assertEqual(repr(take(3, count(10, 2.5))), repr([10, 12.5, 15.0]))
c = count(3, 5)
self.assertEqual(repr(c), 'count(3, 5)')
@ -576,6 +590,10 @@ class TestBasicOps(unittest.TestCase):
self.assertEqual(repr(count(10.5, 1.25)), 'count(10.5, 1.25)')
self.assertEqual(repr(count(10.5, 1)), 'count(10.5)') # suppress step=1 when it's an int
self.assertEqual(repr(count(10.5, 1.00)), 'count(10.5, 1.0)') # do show float values lilke 1.0
self.assertEqual(repr(count(10, 1.00)), 'count(10, 1.0)')
c = count(10, 1.0)
self.assertEqual(type(next(c)), int)
self.assertEqual(type(next(c)), float)
for i in (-sys.maxsize-5, -sys.maxsize+5 ,-10, -1, 0, 10, sys.maxsize-5, sys.maxsize+5):
for j in (-sys.maxsize-5, -sys.maxsize+5 ,-10, -1, 0, 1, 10, sys.maxsize-5, sys.maxsize+5):
# Test repr

3
Misc/NEWS
View File

@ -65,6 +65,9 @@ Core and Builtins
Library
-------
- Issue #28019: itertools.count() no longer rounds non-integer step in range
between 1.0 and 2.0 to 1.
- Issue #25969: Update the lib2to3 grammar to handle the unpacking
generalizations added in 3.5.

45
Modules/itertoolsmodule.c
View File

@ -3905,7 +3905,7 @@ static PyObject *
count_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
countobject *lz;
int slow_mode = 0;
int fast_mode;
Py_ssize_t cnt = 0;
PyObject *long_cnt = NULL;
PyObject *long_step = NULL;
@ -3922,16 +3922,26 @@ count_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
return NULL;
}
fast_mode = (long_cnt == NULL || PyLong_Check(long_cnt)) &&
(long_step == NULL || PyLong_Check(long_step));
/* If not specified, start defaults to 0 */
if (long_cnt != NULL) {
cnt = PyLong_AsSsize_t(long_cnt);
if ((cnt == -1 && PyErr_Occurred()) || !PyLong_Check(long_cnt)) {
PyErr_Clear();
slow_mode = 1;
if (fast_mode) {
assert(PyLong_Check(long_cnt));
cnt = PyLong_AsSsize_t(long_cnt);
if (cnt == -1 && PyErr_Occurred()) {
PyErr_Clear();
fast_mode = 0;
}
}
Py_INCREF(long_cnt);
} else {
cnt = 0;
long_cnt = PyLong_FromLong(0);
if (long_cnt == NULL) {
return NULL;
}
}
/* If not specified, step defaults to 1 */
@ -3947,21 +3957,24 @@ count_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
assert(long_cnt != NULL && long_step != NULL);
/* Fast mode only works when the step is 1 */
step = PyLong_AsLong(long_step);
if (step != 1) {
slow_mode = 1;
if (step == -1 && PyErr_Occurred())
PyErr_Clear();
if (fast_mode) {
assert(PyLong_Check(long_step));
step = PyLong_AsLong(long_step);
if (step != 1) {
fast_mode = 0;
if (step == -1 && PyErr_Occurred())
PyErr_Clear();
}
}
if (slow_mode)
cnt = PY_SSIZE_T_MAX;
else
if (fast_mode)
Py_CLEAR(long_cnt);
else
cnt = PY_SSIZE_T_MAX;
assert((cnt != PY_SSIZE_T_MAX && long_cnt == NULL && !slow_mode) ||
(cnt == PY_SSIZE_T_MAX && long_cnt != NULL && slow_mode));
assert(slow_mode ||
assert((cnt != PY_SSIZE_T_MAX && long_cnt == NULL && fast_mode) ||
(cnt == PY_SSIZE_T_MAX && long_cnt != NULL && !fast_mode));
assert(!fast_mode ||
(PyLong_Check(long_step) && PyLong_AS_LONG(long_step) == 1));
/* create countobject structure */