Wemake-python-styleguide: Detect getters and setters

[sobolevn]

Rule request

Thesis

We can inspect class and instance methods to find these pattern: if class contains two methods like get_X and set_X we should raise UnpythonicGetterSetterViolation

We should also detect cases like:

• class has instance or class level attribute x or _x or __x
• class has method called get_x or set_x

It is oop violation.

Reasoning

Because python does not need this abstraction:

• Either use @property
• Or just make the property public and change it

[Gwin73]

Hi, can I take the issue?

[sobolevn]

Sure! @Gwin73 thanks a lot!

Feel free to ask any questions.

[sobolevn]

@Gwin73 I have updated the task description. Please, take a look 🙂

[ruwaid4]

Hello, i am part of the same group as @Gwin73 who is working on this issue. Just to clarify some things, should it be:

• class has instance or class level attribute x or _x or __x
  AND
• class has method called get_x or set_x?

So when both cases are satisfied we should raise UnpythonicGetterSetterViolation or should we do so when either case is satisfied?

[sobolevn]

When either case is satisfied 🙂 (logical or)

[ruwaid4]

Thanks for the quick answer! So this would mean no instance or class level attributes are allowed since x matches anything?

[sobolevn]

I mean x is an abstract field name. It can be anything. Any name.

[Gwin73]

Wait I think there must be some misunderstanding here. Instance or class level attributes x or _x or __x must be allowed right, as long as they are "public" and have no corresponding get_x or set_x methods?

[Gwin73]

Only allowing properties and NO attributes seems a bit weird.

[sobolevn]

Sorry, that I am not able to express myself clear enough 🙂

This rule only checks method names. We need to detect patterns like get_${existing_attribute_name} and set_${existing_attribute_name} and raise violations when any of these methods are found.

Where ${existing_attribute_name} can be public, protected, or private name of instance or class level attribute.

[ruwaid4]

So it should be:

• class has instance or class level attribute x or _x or __x
  AND
• class has method called get_x or set_x

Logical AND

[sobolevn]

Yes 👍