Invoke: @task doesn't play nice with other decorators

[lsh-0]

The @task decorator doesn't appear to play nicely with other decorators, unlike Fabric. I may not have read this part of the documentation yet, but I wouldn't expect @task to undermine python norms.

For example:

def capture_error(fn):
    @wraps(fn)
    def wrapper(*args, **kwargs):
        try:
            return fn(*args, **kwargs)
        except AssertionError as err:
            print(err)
    return wrapper

@task
@capture_error
def foo(c):
    print('bar')
    raise AssertionError('baz')

this looks fine:

inv foo
>>> bar
>>> baz

but when I add a parameter:

@task
@capture_error
def foo(c, p1):
    print(p1)
    raise AssertionError('baz')

I get:

inv foo bar
>>> No idea what 'bar' is!

The parameter handling docs offer no insight into what the problem is.

[bitprophet]

This is likely an oversight / lack of porting those extra careful parts of Fabric 1's decorator. #246 seems related and may fix it (though it's now kinda old so may need a revisit). Gonna leave this open and in a milestone since it's a regression (which is arguably worse than features which just aren't ported yet). Thanks!

[lsh-0]

hey, thanks for your attention on this. I've been using Fabric for so many years now I'm trialing Invoke on a personal project to unblock some work projects that need the Python3 upgrade as it doesn't look like Fabric will get there, which is frustrating, but I do appreciate your efforts and those of the other contributors.

[bitprophet]

@lsh-0 FWIW, Fabric 2 is technically out now (though it needs a few more feature releases to get up to par with 1.x) and supports Python 3. But it's also built heavily on top of Invoke so working with plain Invoke is a fine place to start; can always use fabric 2's API directly or switch later.

[ewanjones]

For future reference, I found a workaround:

def decorator(fn):
    @functools.wraps(fn)
    def _decorated(ctx, *args, **kwargs):
        return fn(ctx, *args, **kwargs)
    return _decorated

@invoke.task
def some_task(ctx, config="Something"):
    @decorator
    def _inner(ctx):
        print(config)
        ...

    return _inner(ctx)

This allows invoke.task to find the task and inspect the args

[corentinbettiol]

After finding your answer on stackoverflow I also found it here!

I was able to solve my problem by using the @functools.wraps decorator as well :

old decorator:

def ask(task_to_execute):
    """Decorator to ask if the user really wants to perform a task.
    """

    def wrapper(*args, **kwargs):

        y = ["y", "yes", "o", "oui", "Yes", "Oui", "go"]
        if input("Do you want to execute " + task_to_execute.__name__ + "? [y/d/N] ") in y:
            task_to_execute(*args, **kwargs)

    return wrapper

new decorator:

from functools import wraps

def ask(task_to_execute):
    """Decorator to ask if the user really wants to perform a task.
    """

    @wraps(task_to_execute)
    def wrapped_wrapper(*args, **kwargs):

        y = ["y", "yes", "o", "oui", "Yes", "Oui", "go"]
        if input("Do you want to execute " + task_to_execute.__name__ + "? [y/d/N] ") in y:
            task_to_execute(*args, **kwargs)

    return wrapped_wrapper

And so tab-completion works again :)