The purpose of 'functools.wraps' is to make a decorated function look like
the original function, i.e. such that the __name__, __module__, __doc__
attributes are the same as the wrapped function.
However, I've noticed inconsistent behaviour.
Given the following:
import functools
def decorator(func):
@functools.wraps(func)
def wrapper(self):
func(self)
return wrapper
class Klass:
@decorator
def method(self):
raise Exception('boom!')
print('Klass.method:',Klass.method)
k = Klass()
print('k.method',k.method)
try:
k.method(1)
except Exception as e:
print('exception:',e)
The output (Python 3.3) is:
Klass.method: <function Klass.method at 0x7f2d7c454b00>
k.method <bound method Klass.method of <__main__.Klass object at
0x7f2d7c4570d0>>
exception: wrapper() takes 1 positional argument but 2 were given
The first two lines are as expected, using the name of the decorated
function. However, the exception uses the name of the decorating wrapper
function.
Is this a bug in functools? Or is this a language feature? If so, is there a
valid argument to change this behaviour?
-- isedev
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