Rubocop incorrectly tries to transform one line conditional to ternary operator

[Lykos]

Rubocop tries to correct a one line conditional with elsif clauses to a ternary operator, but the way it does it is broken and leads to a syntax error.

Expected behavior

The actual expected behavior is a bit of a product decision that I don't dare to make. It could either leave this line unchanged or transform it to multiple ternary operators.

Actual behavior

Rubocop messes up lines with a one line conditional that contains an elsif clause and the result has a syntax error.

Steps to reproduce the problem

Create a file with the following silly bit of code in an otherwise empty directory:

# frozen_string_literal: true
digit = gets.to_i % 10
nice_digit = if digit >= 5 then 5 elsif digit >= 2 then 2 else 1 end
puts nice_digit

Double check that it works by running it and seeing that you can enter an integer and it produces some output.

Run rubocop -a which will try to correct the one line conditional.

See that the line with the one line conditional is now messed up. Running the file produces a syntax error.

RuboCop version

0.79.0 (using Parser 2.7.0.2, running on ruby 2.5.1 x86_64-linux-gnu)

[Lykos]

I am actually somewhat interested in fixing this myself now. But I need a bit of guidance. I have two questions:

I think the right solution here is to transform it to a multiline conditional if there's an elsif clause. I.e.

if digit >= 5 then 5 elsif digit >= 2 then 2 else 1 end

becomes

if digit >= 5
  5
elsif digit >= 2
  2
else
  1
end

Do you agree?

If not, I guess the solution would be to not autocorrect this and let the user figure out how to refactor. How would something like that be implemented? Can the autocorrect function just do nothing in some cases or does that cause problems?

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contribution and understanding!