Fix Ruby compile time warnings

Everyone can contribute. Help move this issue forward while earning points, leveling up and collecting rewards.

• Close this issue

According to this script which runs ruby -wc (Ruby 2.6.5p114 (2019-10-01 revision 67812)) on the code base we have a couple of warnings which we can easily get rid of.

This issue tracks the progress.

Ideally, we should try to utilize RuboCop's 👮 rules to fix these warnings permanently.

Fixes

• !23074 (merged) - warning: '*' interpreted as argument with ✔️ 👮 Lint/AmbiguousOperator
• !23080 (merged) - warning: assigned but unused variable 🚫 👮 see !23080 (comment 271861210)
• !23165 (merged) - warning: character class has duplicated range 🚫 👮
• !23269 (merged) - warning: possibly useless use of == in void context
• !37440 (merged) - warning: assigned but unused variable again
• ...

Ignored warnings

Currently, this script ignores the following warnings:

• warning: ambiguous first argument; put parentheses or a space even after /' operator`
  • Too much noise for now. We could remove (and fix) this ignore later 👍
• warning: possibly useless use of \| in void context
  • We cannot avoid this warnings in specs when RSpec::Parameterized::TableSyntax used. Example: https://gitlab.com/gitlab-org/gitlab/blob/350bb25818e2bc08be1358036f9f4df427fbd75f/spec/models/issue_spec.rb#L815