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Issue #27870: A left shift of zero by a large integer no longer attempts to allocate large amounts of memory.

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This commit is contained in:
Mark Dickinson 2016-08-29 19:27:06 +01:00
parent 4e1de16f88
commit 82a95277b8
3 changed files with 23 additions and 0 deletions
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15
Lib/test/test_long.py
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@ -878,6 +878,21 @@ class LongTest(unittest.TestCase):
self.check_truediv(-x, y)
self.check_truediv(-x, -y)
def test_lshift_of_zero(self):
self.assertEqual(0 << 0, 0)
self.assertEqual(0 << 10, 0)
with self.assertRaises(ValueError):
0 << -1
@support.cpython_only
def test_huge_lshift_of_zero(self):
# Shouldn't try to allocate memory for a huge shift. See issue #27870.
# Other implementations may have a different boundary for overflow,
# or not raise at all.
self.assertEqual(0 << sys.maxsize, 0)
with self.assertRaises(OverflowError):
0 << (sys.maxsize + 1)
def test_small_ints(self):
for i in range(-5, 257):
self.assertIs(i, i + 0)