Dennis Sweeney <sweeney.dennis...@gmail.com> added the comment:
> other attributes will not be copied
The signature of wraps() is
wraps(wrapped, assigned=('__module__', '__name__', '__qualname__',
'__doc__', '__annotations__'), updated=('__dict__',))
Passing the updated=() will prevent the __dict__ from being updated, but those
other attributes will still be assigned to:
>>> from functools import wraps
>>> def f(x: int) -> int:
... "Square of a number"
... return x ** 2
...
>>> @wraps(f, updated=())
... def g(*args, **kwargs):
... return f(*args, **kwargs)
...
>>> help(g)
Help on function f in module __main__:
f(x: int) -> int
Square of a number
> This is an interoperability bug
This is probably somewhat subjective, but I think the current behavior is okay:
copy all of the attributes of the wrapped function into the wrapper. That's
predictable, well-specified behavior, even if it has unexpected consequences in
some situations -- I would say unusual situations, since 90% of the time I've
seen @wraps used is in making custom decorators, where you really do mean to
copy *all* of the attributes of the old function into the new one, and never
think of the wrapped function again.
My thinking is also that to add a special case for abstract methods in
functools would be to unnecessarily couple the functools module to
implementation details of the ABC module. If someone using the ABC module wants
to not update the __dict__ when using functools.wraps, there's already an easy
switch for that, and it's completely orthogonal to what the __dict__ contains.
For an interesting precedent, @abstractclassmethod was created in
https://bugs.python.org/issue5867 to solve a similar (I think) interoperability
problem between @abstractmethod and @classmethod rather than adding a special
case to @classmethod.
I would be interested in hearing if others want something to change about
wraps().
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Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue43010>
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