auto-correct changes logic

[xithan]

a == a.downcase is changed to a.casecmp(a).zero?
(the former condition is supposed to check if uppercase letters are present; the auto-corrected condition is always true)

return if (!a.include? b) && c is changed to return unless a.include? b && c
(auto-correct converts if ! to unless although there is a second expression involved)

[rrosenblum]

@xithan, the first issue that you mention, pertaining to Perfomance/Casecmp has a more detailed discussion in #2852. Please join the conversation there.

The second one sounds like a bug to me. I assume that the second issue is coming from Style/NegatedIf in combination with Style/ParenthesesAroundCondition or more likely Style/RedundantParentheses. Can you please provide the version of RuboCop that you are using as well as whether or not the listed cops are enabled or disabled.

[xithan]

latest rubocop version 0.37.2 with default style rules. I double-checked with rubocop --show-cops:
Style/NegatedIf enabled
Style/RedundantParentheses enabled
Style/ParenthesesAroundCondition enabled

ParenthesesAroundCondition doesn't matter. With NegatedIf enabled, the other two disabled and removed parentheses return if !a.include? b && c is still changed to return unless a.include? b && c

[rrosenblum]

Running RuboCop on the code produces this output:

test.rb:4:1: C: [Corrected] Style/NegatedIf: Favor unless over if for negative conditions.
return if !a.include? b && c
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
test.rb:4:11: C: [Corrected] Style/RedundantParentheses: Don't use parentheses around an unary operation.
return if (!a.include? b) && c
          ^^^^^^^^^^^^^^^
test.rb:4:15: W: Lint/RequireParentheses: Use parentheses in the method call to avoid confusion about precedence.
return unless a.include? b && c

Breaking it down, the first run will cause an offense in Style/RedundantParentheses. The second run will cause a new offense in Style/NegatedIf.

I think this is an issue with Style/NegatedIf because return if (!a.include?) b && c and return if !a.include? b && c should be equivalent code, but return unless a.include? b && c is not.

[alexdowad]

I think this is an issue with Style/NegatedIf because return if (!a.include?) b && c and return if !a.include? b && c should be equivalent code, but return unless a.include? b && c is not.

Not so. The transformation which NegatedIf is performing is valid. It doesn't look valid, but it is (precedence is a bit deceiving here).

RedundantParentheses is the problem.

[alexdowad]

Just pushing a fix to my open PR.

[rrosenblum]

Thanks for the fix @alexdowad