Naming/UncommunicativeMethodParamName doesn't take into account underscore prefix

[thomthom]

I use Ruby in the domain of 3D modelling. So common short variables include x, y, z and u, v. These are flagged by the default rules of Naming/UncommunicativeMethodParamName so I add them to the list of allowed names:

Naming/UncommunicativeMethodParamName:
  AllowedNames:
    - x
    - y
    - z
    - u
    - v
    - uv

However, some times these names are also used as argument names in callbacks of the API. And you don't always use all the arguments being passed in the callback. For instance:

 def onLButtonDoubleClick(_flags, _x, _y, _view)
  # ...
end

However this then will again flag the x and y arguments:

src/tt_truebend/tools/truebend.rb:195:42: C: Naming/UncommunicativeMethodParamName: Method parameter must be at least 3 characters long.
    def onLButtonDoubleClick(_flags, _x, _y, _view)

I could add _x and _y to the list of allowed names. But this still feels like a bug - where the cop should take into account the convention of using underscore prefix to denote unused arguments.

---

Expected behavior

I would expect Naming/UncommunicativeMethodParamName to take into account the _ prefix convention and strip it away when it checks against the list of allowed short names.

Actual behavior

Currently _x is flagged even if x is an allowed variable name.

Steps to reproduce the problem

Naming/UncommunicativeMethodParamName:
  AllowedNames:
    - x
    - y
    - z

 def onLButtonDoubleClick(_flags, _x, _y, _view)
  # ...
end

RuboCop version

$ [bundle exec] rubocop -V
0.63.1 (using Parser 2.6.0.0, running on ruby 2.2.6 x64-mingw32)

[Drenmi]

I think this sounds like a perfectly reasonable enhancement to the cop. 🙂 Interested in making a PR @thomthom?

[thomthom]

Yea, I can make a PR when I have a spare moment.

[thomthom]

Starting work on this now.