mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-10-17 12:18:23 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 9

SF bug 693121: Set == non-Set is a TypeError.

Browse source 
Allow mixed-type __eq__ and __ne__ for Set objects.  This is messier than
I'd like because Set *also* implements __cmp__.  I know of one glitch now:
cmp(s, t) returns 0 now when s and t are both Sets and s == t, despite
that Set.__cmp__ unconditionally raises TypeError (and by intent).  The
rub is that __eq__ gets tried first, and the x.__eq__(y) True result
convinces Python that cmp(x, y) is 0 without even calling Set.__cmp__.
This commit is contained in:
Tim Peters 2003-03-02 00:19:49 +00:00
parent 3ba491e6b1
commit 44f14b0399
3 changed files with 61 additions and 23 deletions
Download patch file Download diff file Expand all files Collapse all files

35
Lib/test/test_sets.py
View file

@ -232,7 +232,16 @@ class TestBinaryOps(unittest.TestCase):
def test_cmp(self):
a, b = Set('a'), Set('b')
self.assertRaises(TypeError, cmp, (a,b))
self.assertRaises(TypeError, cmp, a, b)
# You can view this as a buglet: cmp(a, a) does not raise TypeError,
# because __eq__ is tried before __cmp__, and a.__eq__(a) returns,
# which Python thinks is good enough to synthesize a cmp() result
# without calling __cmp__.
self.assertEqual(cmp(a, a), 0)
self.assertRaises(TypeError, cmp, a, 12)
self.assertRaises(TypeError, cmp, "abc", a)
#==============================================================================
@ -476,17 +485,19 @@ class TestSubsetNonOverlap(TestSubsets):
class TestOnlySetsInBinaryOps(unittest.TestCase):
def test_cmp(self):
try:
self.other == self.set
self.fail("expected TypeError")
except TypeError:
pass
try:
self.set != self.other
self.fail("expected TypeError")
except TypeError:
pass
def test_eq_ne(self):
# Unlike the others, this is testing that == and != *are* allowed.
self.assertEqual(self.other == self.set, False)
self.assertEqual(self.set == self.other, False)
self.assertEqual(self.other != self.set, True)
self.assertEqual(self.set != self.other, True)
def test_ge_gt_lt_le(self):
# Unlike the others, this is testing that == and != *are* allowed.
self.assertRaises(TypeError, lambda: self.set < self.other)
self.assertRaises(TypeError, lambda: self.set <= self.other)
self.assertRaises(TypeError, lambda: self.set > self.other)
self.assertRaises(TypeError, lambda: self.set >= self.other)
def test_union_update(self):
try: