decorator module vs functools.wraps

Question

The functionality of the decorator module and functools.wraps is closely related. What are the differences between the two (as of Python 3.3 / 3.4)?

I am aware of one difference: 3+ years ago, decorator supported help, while wraps didn't (see also this).

Answer 1

One of the main differences is listed right in the documentation you linked to: decorator preserves the signature of the wrapped function, while wraps does not.

Answer 2

Per the discussion with BrenBarn, nowadays functools.wraps also preserves the signature of the wrapped function. IMHO this makes the decorator decorator almost obsolete.

from inspect import signature
from functools import wraps

def dec(func):
    def wrapper(*args, **kwargs):
        return func(*args, **kwargs)
    return wrapper

def dec2(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        return func(*args, **kwargs)
    return wrapper

def foo(a: int, b):
    pass

print(signature(dec(foo)))
print(signature(dec2(foo)))

# Prints:
# (*args, **kwargs)
# (a:int, b)

Note that one has to use signature and not getargspec. Tested with python 3.4.