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class Descriptor:
def __get__(self, obj, cls):
print("get")
print(type(obj) is Main)
print(cls is Main)
return "result"
def __set__(self, obj, val):
print("set")
print(type(obj) is Main)
print(val)
def __delete__(self, obj):
print("delete")
print(type(obj) is Main)
def __set_name__(self, owner, name):
print("set_name", name)
print(owner.__name__ == "Main")
class Main:
Forward = Descriptor()
m = Main()
try:
m.__class__
except AttributeError:
# Target doesn't support __class__.
print("SKIP")
raise SystemExit
r = m.Forward
if "Descriptor" in repr(r.__class__):
# Target doesn't support descriptors.
print("SKIP")
raise SystemExit
# Test assignment and deletion.
print(r)
m.Forward = "a"
del m.Forward
# Test that lookup of descriptors like __get__ are not passed into __getattr__.
class NonDescriptor:
def __getattr__(self, attr):
print("getattr", attr)
class TestClass:
non_descriptor = NonDescriptor()
print(isinstance(TestClass().non_descriptor, NonDescriptor))
t = TestClass()
t.non_descriptor = 123
print(t.non_descriptor)
try:
del TestClass().non_descriptor
except AttributeError:
print("AttributeError")
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