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Issue #8748: Fix two issues with comparisons between complex and integer

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objects.  (1) The comparison could incorrectly return True in some cases
(2**53+1 == complex(2**53) == 2**53), breaking transivity of equality.
(2) The comparison raised an OverflowError for large integers, leading
to unpredictable exceptions when combining integers and complex objects
in sets or dicts.

Patch by Meador Inge.
This commit is contained in:
Mark Dickinson 2010-05-21 14:55:26 +00:00
parent f0feec2cb6
commit cc6a982de8
3 changed files with 81 additions and 9 deletions
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25
Lib/test/test_complex.py
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@ -110,12 +110,18 @@ class ComplexTest(unittest.TestCase):
self.assertRaises(TypeError, complex.__floordiv__, 3+0j, 0+0j)
def test_richcompare(self):
self.assertRaises(OverflowError, complex.__eq__, 1+1j, 1<<10000)
self.assertIs(complex.__eq__(1+1j, 1<<10000), False)
self.assertIs(complex.__lt__(1+1j, None), NotImplemented)
self.assertIs(complex.__eq__(1+1j, 1+1j), True)
self.assertIs(complex.__eq__(1+1j, 2+2j), False)
self.assertIs(complex.__ne__(1+1j, 1+1j), False)
self.assertIs(complex.__ne__(1+1j, 2+2j), True)
for i in range(1, 100):
f = i / 100.0
self.assertIs(complex.__eq__(f+0j, f), True)
self.assertIs(complex.__ne__(f+0j, f), False)
self.assertIs(complex.__eq__(complex(f, f), f), False)
self.assertIs(complex.__ne__(complex(f, f), f), True)
self.assertIs(complex.__lt__(1+1j, 2+2j), NotImplemented)
self.assertIs(complex.__le__(1+1j, 2+2j), NotImplemented)
self.assertIs(complex.__gt__(1+1j, 2+2j), NotImplemented)
@ -129,6 +135,23 @@ class ComplexTest(unittest.TestCase):
self.assertIs(operator.ne(1+1j, 1+1j), False)
self.assertIs(operator.ne(1+1j, 2+2j), True)
def test_richcompare_boundaries(self):
def check(n, deltas, is_equal, imag = 0.0):
for delta in deltas:
i = n + delta
z = complex(i, imag)
self.assertIs(complex.__eq__(z, i), is_equal(delta))
self.assertIs(complex.__ne__(z, i), not is_equal(delta))
# For IEEE-754 doubles the following should hold:
# x in [2 ** (52 + i), 2 ** (53 + i + 1)] -> x mod 2 ** i == 0
# where the interval is representable, of course.
for i in range(1, 10):
pow = 52 + i
mult = 2 ** i
check(2 ** pow, range(1, 101), lambda delta: delta % mult == 0)
check(2 ** pow, range(1, 101), lambda delta: False, float(i))
check(2 ** 53, range(-100, 0), lambda delta: True)
def test_mod(self):
# % is no longer supported on complex numbers
self.assertRaises(TypeError, (1+1j).__mod__, 0+0j)