(PUP-11993) The rest of the Style/Redundant* cops!

[AriaXLi]

No description provided.

[joshcooper]

For posterity, the Redundant/Self is auto-correct safe, but there is a subtle issue to be aware of. If the method being called is a writer/accessor, then you have to use self. For example, here's a class Foo with an accessor name:

❯ cat setter.rb 
# frozen_string_literal: true

class Foo
  attr_accessor :name

  def noself(arg)
    name = arg
  end

  def useself(arg)
    self.name = arg
  end
end

f = Foo.new
f.noself('a')
puts "name '#{f.name}'"
f.useself('a')
puts "name '#{f.name}'"

Note the noself and useself methods behave differently:

❯ bx ruby setter.rb
name ''
name 'a'

This occurs because the noself method actually creates a temporary variable named name instead of calling the accessor!!

Rubocop does detect that the noself method isn't doing what it should and we have that cop enabled:

❯ bx rubocop setter.rb
...
setter.rb:7:5: W: [Correctable] Lint/UselessAssignment: Useless assignment to variable - name.
    name = arg
    ^^^^

And rubocop seems to have left alone places where a writer/accessor are being called:

❯ git grep -E 'self\.\w+ = ' lib | head
lib/puppet/application.rb:      self.run_status = nil
lib/puppet/application.rb:      self.run_status = :stop_requested
lib/puppet/application.rb:      self.run_status = :restart_requested
lib/puppet/application/face_base.rb:    self.render_as = format.to_sym
lib/puppet/file_serving/base.rb:    self.path = path
lib/puppet/file_serving/base.rb:    self.links = links if links
lib/puppet/file_serving/base.rb:    self.relative_path = relative_path if relative_path
lib/puppet/file_serving/base.rb:    self.source = source if source
lib/puppet/file_serving/fileset.rb:    self.ignore = []
lib/puppet/file_serving/fileset.rb:    self.links = :manage
...

So I think the RedundantSelf changes are ok.