Need help on reducing cognitive complexity

[Sencer Hamarat]

Hi everyone,

I have a code block with high cognitive complexity below:

    @staticmethod
    def in_circle_check(obj_type, item, uuid, item_is_array=False):

        if obj_type not in ['trees', 'flowers']:
            return None

        plant = get_plant_with_circles(uuid)
        if not plant:
            return None

        if obj_type == 'trees':
            if plant['in_all_tree_types']:
                return True
            circle_objects = plant['tree_circle']['items']
        else:
            if plant['in_all_flower_types']:
                return True
            circle_objects = plant['flower_circle']['items']

        if isinstance(circle_objects, list):
            if item_is_array:
                for item in item:
                    if item not in circle_objects:
                        return -1
                return True
            else:
                if item in circle_objects:
                    return True
        else:
            return -1

        return -1


I try to move the first 3 if statements on the beginning of the block into new methods but that maneuver ends up with raising complexity.

Can anybody help me to learn how to reduce cognitive complexity in code blocks like this?

Kind regards,

Sencer HAMARAT

[Agnese Camellini]

The only things that comes into my mind is taking away that first if which is redundant with the third block.

An other way might be to include all the if in a big switch...

My 2 cents

Agnese

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[Mike Dewhirst]

On 21/07/2022 3:52 pm, Sencer Hamarat wrote:
> Hi everyone,
>
> I have a code block with high cognitive complexity below:
>
>     @staticmethod
>     def in_circle_check(obj_type, item, uuid, item_is_array=False):

Partly because the args seem weird.

Try writing a docstring which says what the method needs to do. Then
rewrite the code as nested if statements, bearing in mind that if
nothing fits, it will fall through to the end and return either None or
whatever you want to return, perhaps -1.

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[Shaheed Haque]

The first step is to ensure you have a precise and accurate understanding of the code before optimization. Right now, I am suspicious of at least 2 things in the code. 

First, the function returns any of {None, -1, True}. While this is certainly allowed, is this correct? If not, please correct the code. If so, then can you explain the rule that governs the return type (assuming it is not literally what is written). 

Second, as your previous respond ant hinted, the first 2 lines look like an optimisation attempt, except for the return type issue. Can you clarify if the purpose of these lines is optimisation, or not? 

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[Michael Thomas]

Personally I think the code has a very weird "smell"... Assuming you don't have any way of rewriting the calling code and are stuck with editing this single method, I'd suggest something along the lines of:

@staticmethod
def in_circle_check(obj_type, item, uuid):

    if obj_type not in ['trees', 'flowers']:
        return None

    # trim the trailing 's', so this can be used elsewhere...
    obj_type = obj_type[:-1]

    if not (plant := get_plant_with_circles(uuid)):
        return None

    if plant[f'in_all_{obj_type}_types']:
        return True

    circle_objects = plant[f'{obj_type}_circle']['items']

    if isinstance(circle_objects, list):
        if not isinstance(item, (list, tuple)):
            items = item
        else:
            items = [item]

        if all([i in circle_objects for i in items]):
            return True

    return -1

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