False Style/RedundantSelf on static method

[abitrolly]

Actual behavior

In this GitHub job https://github.com/Homebrew/brew/actions/runs/7091523800/job/19300839843?pr=16238#step:6:15

self.name_for_url is the static method in the same class. Removing self from it results in the following error.

Expected behavior

Let static method calls pass. Or provide sufficient explanation why static method calls are bad.

Steps to reproduce the problem

This is extremely important! Providing us with a reliable way to reproduce
a problem will expedite its solution.

RuboCop version

Include the output of rubocop -V or bundle exec rubocop -V if using Bundler.
If you see extension cop versions (e.g. rubocop-performance, rubocop-rspec, and others)
output by rubocop -V, include them as well. Here's an example:

$ [bundle exec] rubocop -V
1.58.0 (using Parser 3.2.2.3, rubocop-ast 1.29.0, running on ruby 3.2.2) [x86_64-linux]
  - rubocop-performance 1.18.0
  - rubocop-rspec 2.23.2

[vlad-pisanov]

If name_from_url is a class method, then calling self.name_from_url from an instance method wouldn't work anyways. You'd have to do self.class.name_from_url.

At least that's what's happening in: https://github.com/Homebrew/brew/blob/9f65f120f3fef7263a646d3f690098751c02e078/Library/Homebrew/formula_creator.rb#L50-L51

[abitrolly]

You're right. The self.name_from_url didn't work. The syntax that works is FormulaCreator.name_from_url without self.

I still feel that rubocop should be smarter in this way and do not propose the misleading solution. The case like this should have been caught by tests, but test are often run only after linter.

[fatkodima]

I still feel that rubocop should be smarter in this way and do not propose the misleading solution. The case like this should have been caught by tests, but test are often run only after linter.

There is no way rubocop can help with this.

[abitrolly]

@fatkodima can rubocop detect that there is no self.whatever method?

[fatkodima]

No, rubocop is a static analysis tool, meaning that it analyzes code without executing it.

[abitrolly]

@fatkodima I am not an expert in Ruby static analysis. Does rubocop read a list of methods in a class?

[fatkodima]

It can read, but it does not do that most of the time. And this will be hard (read "impossible"), because you can define methods in parent classes, inside included modules, via metaprogramming.

[abitrolly]

@fatkodima but rubocop does read... no? Well, I see now. The message "Method .... does not exist" in the issue description comes from sorbet check.

I guess there is no way rubocop can query sorbet for a list of valid methods in this context.