Consider renaming __constraints to __cloup_constraints__

[pocek]

Please consider renaming __constraints to __cloup_constraints__. Although at first it may sound like bikeshedding, they are valid reasons to do so:

1. In classes, names like __name__ don't get mangled, but names like __name do (as described in https://docs.python.org/3/reference/expressions.html#private-name-mangling). It matters if you decorate a callback with a (callable) class, not just a function. And, if you do that, accessing __constraints for reasons like copying/moving them into another object gets tricky, because it's private. It's still possible though, but one has to use setattr/getattr/delattr family of functions instead of simple attribute access and del.

2. It would be similar to what click does with __click_params__. With __click_params__, one can simply and happily copy/move them without resorting to setattr/getattr/delattr method.

3. The name would be clearer - it's not obvious what __constraints are. I believe __cloup_constraints__ is simply a better name.

[janluke]

Did this cause an actual problem to you? If yes, I'd be interested in reading an example.

[janluke]

one can simply and happily copy/move them without resorting to setattr/getattr/delattr method.

I think I named it __constraints exactly to communicate that this is private API. But I think I'm okay with the change you're proposing. Do you want to open a PR?

[pocek]

Did this cause an actual problem to you? If yes, I'd be interested in reading an example.

Yes, it's a real problem I have encountered in a construct like this:

import cloup
from cloup.constraints import mutually_exclusive

class ClassBasedDecorator:
    def __init__(self, func):
        self.func = func

        # Standard attributes used by click
        self.__name__ = func.__name__
        self.__doc__ = func.__doc__

        if hasattr(func, '__click_params__'):
            self.__click_params__ = func.__click_params__
            del func.__click_params__

        # Cloup makes it harder
        if hasattr(func, '__constraints'):
            setattr(self, '__constraints',  getattr(func, '__constraints'))
            delattr(func, '__constraints')

    def __call__(self, *args, **kwargs):
        return self.func(*args, **kwargs)

@cloup.command(show_constraints=True)
@ClassBasedDecorator
@cloup.option('--foo')
@cloup.option('--bar')
@cloup.constraint(mutually_exclusive, ['foo', 'bar'])
def hello(foo, bar):
    """Hello"""
    print('hello')

hello()

I hope it doesn't look too unconventional - to have the decorators ordered like this, but this is the way that makes sense in my application.

Do you want to open a PR?

OK, I can to that.

[janluke]

Yes, it's a real problem I have encountered in a construct like this. [...] I hope it doesn't look too unconventional - to have the decorators ordered like this, but this is the way that makes sense in my application.

The construct was already clear but I was curious about the real use case which requires you to mess with __constraints. Anyway, it's fine, don't feel obliged to share the details. I'll wait for the PR :)