Infinity loop in Style/YodaCondition autofix

[ShockwaveNN]

Steps to reproduce the problem

1. Create temp.rb file

p 'a' if :a == :b

2. Run rubocop -a temp.rb. This cause exception
   Infinite loop detected in /path/test.rb

RuboCop version

$ rubocop -V
0.49.0 (using Parser 2.4.0.0, running on ruby 2.1.10 x86_64-linux)

[bbatsov]

Seems we didn't account for situations where both sides of an expression are some literals. :-)

[martinmosegaard]

I can also reproduce it with this code:

def test_yoda
  list = [{ number: 1 }]
  list.count { |elm| elm.number == 1 } > 0
end

• It reports a violation, although I would not like to reverse any operands
• It crashes with check_for_infinite_loop in autocorrect mode

[smakagon]

@bbatsov my bad, missed that case. Thanks guys for fixing that really quick.

[eagletmt]

I've found another false-positive case self == var and this case is also fixed by the commit 5700720 .

@bbatsov Could you release a new version? This bug looks critical to me.

[bbatsov]

I'll likely do this after the weekend. I don't view the bug as critical as it affects a single cop which can easily be disabled.

[dankohn]

The following code produces YodaCondition errors in both directions:

module StringRefinements
  refine String do
    def met?
      self == 'Met'
    end
  end
end

Here are the errors:

rubocop app/models/concerns/string_refinements.rb 
Inspecting 1 file
C
1  Style/YodaCondition
--
1  Total



Offenses:

app/models/concerns/string_refinements.rb:6:7: C: Style/YodaCondition: Reverse the order of the operands 'Met' == self. (https://en.wikipedia.org/wiki/Yoda_conditions)
      'Met' == self
      ^^^^^^^^^^^^^

1 file inspected, 1 offense detected

$ rubocop app/models/concerns/string_refinements.rb 
Inspecting 1 file
C
1  Style/YodaCondition
--
1  Total



Offenses:

app/models/concerns/string_refinements.rb:6:7: C: Style/YodaCondition: Reverse the order of the operands self == 'Met'. (https://en.wikipedia.org/wiki/Yoda_conditions)
      self == 'Met'
      ^^^^^^^^^^^^^

1 file inspected, 1 offense detected