New cop to replace conditional assignment with or-assignment

[fatkodima]

I've written the following code

def lock_retrier=(value)
  if value.nil?
    @lock_retrier = NullLockRetrier.new
  else
    @lock_retrier = value
  end
end

But then realized that this should be really written as

def lock_retrier=(value)
  @lock_retrier = value || NullLockRetrier.new
end

and wondering why rubocop hasn't suggested such change.

Quick search on the rails codebase via regexp revealed this:
https://github.com/rails/rails/blob/296ef7a17221e81881e38b51aa2b014d7a28bac5/actionpack/lib/action_dispatch/journey/gtg/transition_table.rb#L75-L79

So I suggest implementing a new cop (not sure about its name).

This should also check for cases like

if value
  @lock_retrier = value
else
  @lock_retrier =  NullLockRetrier.new
end

etc.

[bbatsov]

Seems like a good idea to me. I think we have a couple of similar cops already.

[marcospedro97]

Can I give it a try? Maybe we can call it something like Style/OrAssignment?

[fatkodima]

@marcospedro97 Yes, please, go ahead 👍

[marcospedro97]

I've found a cop with this name already, and it's behaviour is too different from the one we're talking about, thinking about naming it Style/SingleLineOrAssginment, there's also another with the name conditional assignment, also too diferent