Proposition: Disable `Style/CaseEquality` about ruby-style-guide HOT 5 CLOSED

I'm positive to this proposal. I had this problem a few times already.

About the tangent, I think we should evaluate case by case. The Rails/DynamicFinder which is not part of the styleguide is fine to disable in the app I know we are using it because that app uses sorbet and those dynamic methods are not going to be in the rbis. I'm not sure that will be the case of all other rules that have different semantics.

from ruby-style-guide.

If I understood correctly, the proposition to not discourage === is because it is a better way to check hierarchy membership than is_a? or kind_of?. And the reason why it is better is because instances of BasicObject don't respond to is_a? or kind_of? but it does respond to ===. I see a few problems with that:

• AFAIK instances of BasicObject don't respond to === either.
• In Objects, === is not a substitute for is_a? or kind_of?. The former is intended to be used for case statements while the latter is the actual method to check for superclasses.

obj === other → true or false
Case Equality – For class Object, effectively the same as calling #==, but typically overridden by descendants to provide meaningful semantics in case statements.

is_a?(class) → true or false
Returns true if class is the class of obj, or if class is one of the superclasses of obj or modules included in obj.

The reason why we discourage usage of === is because it is supposed to be called implicitly on case statements and not to be used for hierarchy checks.

from ruby-style-guide.

BasicObject is an instance of Class and responds to ===, the instances of BasicObject are irrelevant.

from ruby-style-guide.

BasicObject is an instance of Class and responds to ===, the instances of BasicObject are irrelevant.

So if the point here is about BasicObject itself and not its instances then it also responds to is_a? and kind_of?.

from ruby-style-guide.

I don't understand what you mean here ^.

To do the "typechecking" you don't call instance === class, you call class === instance. The fact that instances don't have === is irrelevant. The fact that instances don't have is_a? is very relevant.

from ruby-style-guide.