Dynamic attribute name causes Rails/ReadWriteAttribute to fail

[davidenglishmusic]

I have a stress case that causes the Rails/ReadWriteAttribute cop to fail for both read_attribute and write_attribute infractions. I have a method that should either return a value if present or commit a new value to that field.

---

Expected behavior

Rubocop should not throw an error.

Actual behavior

It throws an error:

% bundle exec rubocop -a app/models/klass.rb
Scanning app/models/klass.rb
An error occurred while Rails/ReadWriteAttribute cop was inspecting app/models/klass.rb:5:12.
undefined method `value' for s(:lvar, :attr):RuboCop::AST::Node
.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-rails-2.13.1/lib/rubocop/cop/rails/read_write_attribute.rb:70:in `block in within_shadowing_method?'
...
An error occurred while Rails/ReadWriteAttribute cop was inspecting app/models/klass.rb:8:6.
undefined method `value' for s(:lvar, :attr):RuboCop::AST::Node
rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-rails-2.13.1/lib/rubocop/cop/rails/read_write_attribute.rb:70:in `block in within_shadowing_method?'

Steps to reproduce the problem

Enable the cop and run rubocop on the following code:

class Klass < ApplicationRecord
  def attr_or_query(attr, val)
    if (x = read_attribute(attr).present?)
      x
    else
      write_attribute(attr, val)
    end
  end
end

RuboCop version

$ [bundle exec] rubocop -V
1.24.1 (using Parser 3.0.3.2, rubocop-ast 1.15.1, running on ruby 2.6.6 -darwin20)
  - rubocop-performance 1.13.1
  - rubocop-rails 2.13.1
  - rubocop-rspec 2.7.0

[pirj]

Luckily, the fix for this is underway, see #619
I've tested and it fixes your case.

[koic]

I will a bugfix release in a few days after merging #619.