348 lines
11 KiB
Python
348 lines
11 KiB
Python
"""Unit tests for zero-argument super() & related machinery."""
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import sys
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import unittest
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import warnings
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from test.support import check_warnings
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class A:
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def f(self):
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return 'A'
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@classmethod
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def cm(cls):
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return (cls, 'A')
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class B(A):
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def f(self):
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return super().f() + 'B'
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@classmethod
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def cm(cls):
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return (cls, super().cm(), 'B')
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class C(A):
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def f(self):
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return super().f() + 'C'
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@classmethod
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def cm(cls):
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return (cls, super().cm(), 'C')
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class D(C, B):
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def f(self):
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return super().f() + 'D'
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def cm(cls):
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return (cls, super().cm(), 'D')
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class E(D):
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pass
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class F(E):
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f = E.f
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class G(A):
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pass
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class TestSuper(unittest.TestCase):
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def tearDown(self):
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# This fixes the damage that test_various___class___pathologies does.
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nonlocal __class__
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__class__ = TestSuper
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def test_basics_working(self):
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self.assertEqual(D().f(), 'ABCD')
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def test_class_getattr_working(self):
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self.assertEqual(D.f(D()), 'ABCD')
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def test_subclass_no_override_working(self):
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self.assertEqual(E().f(), 'ABCD')
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self.assertEqual(E.f(E()), 'ABCD')
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def test_unbound_method_transfer_working(self):
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self.assertEqual(F().f(), 'ABCD')
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self.assertEqual(F.f(F()), 'ABCD')
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def test_class_methods_still_working(self):
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self.assertEqual(A.cm(), (A, 'A'))
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self.assertEqual(A().cm(), (A, 'A'))
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self.assertEqual(G.cm(), (G, 'A'))
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self.assertEqual(G().cm(), (G, 'A'))
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def test_super_in_class_methods_working(self):
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d = D()
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self.assertEqual(d.cm(), (d, (D, (D, (D, 'A'), 'B'), 'C'), 'D'))
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e = E()
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self.assertEqual(e.cm(), (e, (E, (E, (E, 'A'), 'B'), 'C'), 'D'))
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def test_super_with_closure(self):
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# Issue4360: super() did not work in a function that
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# contains a closure
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class E(A):
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def f(self):
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def nested():
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self
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return super().f() + 'E'
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self.assertEqual(E().f(), 'AE')
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def test_various___class___pathologies(self):
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# See issue #12370
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class X(A):
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def f(self):
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return super().f()
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__class__ = 413
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x = X()
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self.assertEqual(x.f(), 'A')
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self.assertEqual(x.__class__, 413)
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class X:
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x = __class__
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def f():
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__class__
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self.assertIs(X.x, type(self))
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with self.assertRaises(NameError) as e:
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exec("""class X:
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__class__
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def f():
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__class__""", globals(), {})
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self.assertIs(type(e.exception), NameError) # Not UnboundLocalError
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class X:
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global __class__
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__class__ = 42
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def f():
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__class__
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self.assertEqual(globals()["__class__"], 42)
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del globals()["__class__"]
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self.assertNotIn("__class__", X.__dict__)
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class X:
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nonlocal __class__
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__class__ = 42
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def f():
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__class__
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self.assertEqual(__class__, 42)
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def test___class___instancemethod(self):
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# See issue #14857
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class X:
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def f(self):
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return __class__
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self.assertIs(X().f(), X)
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def test___class___classmethod(self):
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# See issue #14857
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class X:
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@classmethod
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def f(cls):
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return __class__
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self.assertIs(X.f(), X)
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def test___class___staticmethod(self):
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# See issue #14857
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class X:
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@staticmethod
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def f():
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return __class__
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self.assertIs(X.f(), X)
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def test___class___new(self):
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# See issue #23722
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# Ensure zero-arg super() works as soon as type.__new__() is completed
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test_class = None
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class Meta(type):
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def __new__(cls, name, bases, namespace):
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nonlocal test_class
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self = super().__new__(cls, name, bases, namespace)
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test_class = self.f()
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return self
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class A(metaclass=Meta):
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@staticmethod
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def f():
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return __class__
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self.assertIs(test_class, A)
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def test___class___delayed(self):
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# See issue #23722
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test_namespace = None
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class Meta(type):
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def __new__(cls, name, bases, namespace):
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nonlocal test_namespace
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test_namespace = namespace
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return None
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# This case shouldn't trigger the __classcell__ deprecation warning
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with check_warnings() as w:
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warnings.simplefilter("always", DeprecationWarning)
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class A(metaclass=Meta):
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@staticmethod
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def f():
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return __class__
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self.assertEqual(w.warnings, [])
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self.assertIs(A, None)
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B = type("B", (), test_namespace)
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self.assertIs(B.f(), B)
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def test___class___mro(self):
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# See issue #23722
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test_class = None
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class Meta(type):
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def mro(self):
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# self.f() doesn't work yet...
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self.__dict__["f"]()
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return super().mro()
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class A(metaclass=Meta):
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def f():
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nonlocal test_class
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test_class = __class__
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self.assertIs(test_class, A)
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def test___classcell___expected_behaviour(self):
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# See issue #23722
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class Meta(type):
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def __new__(cls, name, bases, namespace):
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nonlocal namespace_snapshot
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namespace_snapshot = namespace.copy()
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return super().__new__(cls, name, bases, namespace)
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# __classcell__ is injected into the class namespace by the compiler
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# when at least one method needs it, and should be omitted otherwise
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namespace_snapshot = None
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class WithoutClassRef(metaclass=Meta):
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pass
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self.assertNotIn("__classcell__", namespace_snapshot)
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# With zero-arg super() or an explicit __class__ reference,
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# __classcell__ is the exact cell reference to be populated by
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# type.__new__
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namespace_snapshot = None
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class WithClassRef(metaclass=Meta):
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def f(self):
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return __class__
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class_cell = namespace_snapshot["__classcell__"]
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method_closure = WithClassRef.f.__closure__
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self.assertEqual(len(method_closure), 1)
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self.assertIs(class_cell, method_closure[0])
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# Ensure the cell reference *doesn't* get turned into an attribute
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with self.assertRaises(AttributeError):
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WithClassRef.__classcell__
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def test___classcell___missing(self):
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# See issue #23722
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# Some metaclasses may not pass the original namespace to type.__new__
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# We test that case here by forcibly deleting __classcell__
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class Meta(type):
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def __new__(cls, name, bases, namespace):
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namespace.pop('__classcell__', None)
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return super().__new__(cls, name, bases, namespace)
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# The default case should continue to work without any warnings
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with check_warnings() as w:
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warnings.simplefilter("always", DeprecationWarning)
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class WithoutClassRef(metaclass=Meta):
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pass
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self.assertEqual(w.warnings, [])
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# With zero-arg super() or an explicit __class__ reference, we expect
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# __build_class__ to emit a DeprecationWarning complaining that
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# __class__ was not set, and asking if __classcell__ was propagated
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# to type.__new__.
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# In Python 3.7, that warning will become a RuntimeError.
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expected_warning = (
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'__class__ not set.*__classcell__ propagated',
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DeprecationWarning
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)
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with check_warnings(expected_warning):
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warnings.simplefilter("always", DeprecationWarning)
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class WithClassRef(metaclass=Meta):
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def f(self):
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return __class__
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# Check __class__ still gets set despite the warning
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self.assertIs(WithClassRef().f(), WithClassRef)
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# Check the warning is turned into an error as expected
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with warnings.catch_warnings():
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warnings.simplefilter("error", DeprecationWarning)
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with self.assertRaises(DeprecationWarning):
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class WithClassRef(metaclass=Meta):
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def f(self):
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return __class__
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def test___classcell___overwrite(self):
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# See issue #23722
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# Overwriting __classcell__ with nonsense is explicitly prohibited
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class Meta(type):
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def __new__(cls, name, bases, namespace, cell):
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namespace['__classcell__'] = cell
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return super().__new__(cls, name, bases, namespace)
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for bad_cell in (None, 0, "", object()):
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with self.subTest(bad_cell=bad_cell):
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with self.assertRaises(TypeError):
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class A(metaclass=Meta, cell=bad_cell):
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pass
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def test___classcell___wrong_cell(self):
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# See issue #23722
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# Pointing the cell reference at the wrong class is also prohibited
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class Meta(type):
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def __new__(cls, name, bases, namespace):
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cls = super().__new__(cls, name, bases, namespace)
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B = type("B", (), namespace)
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return cls
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with self.assertRaises(TypeError):
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class A(metaclass=Meta):
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def f(self):
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return __class__
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def test_obscure_super_errors(self):
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def f():
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super()
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self.assertRaises(RuntimeError, f)
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def f(x):
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del x
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super()
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self.assertRaises(RuntimeError, f, None)
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class X:
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def f(x):
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nonlocal __class__
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del __class__
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super()
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self.assertRaises(RuntimeError, X().f)
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def test_cell_as_self(self):
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class X:
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def meth(self):
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super()
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def f():
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k = X()
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def g():
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return k
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return g
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c = f().__closure__[0]
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self.assertRaises(TypeError, X.meth, c)
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def test_super_init_leaks(self):
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# Issue #26718: super.__init__ leaked memory if called multiple times.
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# This will be caught by regrtest.py -R if this leak.
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# NOTE: Despite the use in the test a direct call of super.__init__
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# is not endorsed.
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sp = super(float, 1.0)
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for i in range(1000):
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super.__init__(sp, int, i)
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if __name__ == "__main__":
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unittest.main()
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