当装饰器机制是类时，类成员上的Python装饰器会失败

Python decorators on class members fail when decorator mechanism is a class

当创建用于类方法的装饰器时，当装饰器机制是类而不是函数/闭包时，我遇到了麻烦。使用类窗体时，我的修饰器不会被视为绑定方法。

一般来说，我更喜欢使用修饰符的函数形式，但在本例中，我必须使用现有的类来实现我所需要的。

这看起来似乎与python-decorator-makes-function-forget-that-it-lossed-to-a-class有关，但是为什么它对于函数形式来说工作得很好呢？

这是我能举的最简单的例子来展示所有的进展。对于代码的数量感到抱歉：

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def decorator1(dec_param):
def decorator(function):
print 'decorator1 decoratoring:', function
def wrapper(*args):
print 'wrapper(%s) dec_param=%s' % (args, dec_param)
function(*args)
return wrapper
return decorator

class WrapperClass(object):
def __init__(self, function, dec_param):
print 'WrapperClass.__init__ function=%s dec_param=%s' % (function, dec_param)
self.function = function
self.dec_param = dec_param

def __call__(self, *args):
print 'WrapperClass.__call__(%s, %s) dec_param=%s' % (self, args, self.dec_param)
self.function(*args)

def decorator2(dec_param):
def decorator(function):
print 'decorator2 decoratoring:', function
return WrapperClass(function, dec_param)
return decorator

class Test(object):
@decorator1(dec_param=123)
def member1(self, value=1):
print 'Test.member1(%s, %s)' % (self, value)

@decorator2(dec_param=456)
def member2(self, value=2):
print 'Test.member2(%s, %s)' % (self, value)

@decorator1(dec_param=123)
def free1(value=1):
print 'free1(%s)' % (value)

@decorator2(dec_param=456)
def free2(value=2):
print 'free2(%s)' % (value)

test = Test()
print '
====member1===='
test.member1(11)

print '
====member2===='
test.member2(22)

print '
====free1===='
free1(11)

print '
====free2===='
free2(22)

输出：

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decorator1 decoratoring: <function member1 at 0x3aba30>
decorator2 decoratoring: <function member2 at 0x3ab8b0>
WrapperClass.__init__ function=<function member2 at 0x3ab8b0> dec_param=456
decorator1 decoratoring: <function free1 at 0x3ab9f0>
decorator2 decoratoring: <function free2 at 0x3ab970>
WrapperClass.__init__ function=<function free2 at 0x3ab970> dec_param=456

====member1====
wrapper((<__main__.Test object at 0x3af5f0>, 11)) dec_param=123
Test.member1(<__main__.Test object at 0x3af5f0>, 11)

====member2====
WrapperClass.__call__(<__main__.WrapperClass object at 0x3af590>, (22,)) dec_param=456
Test.member2(22, 2) <<<- Badness HERE!

====free1====
wrapper((11,)) dec_param=123
free1(11)

====free2====
WrapperClass.__call__(<__main__.WrapperClass object at 0x3af630>, (22,)) dec_param=456
free2(22)

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