Unsafe Style/IfUnlessModifier Autocorrection for Code Using defined?

[chadrschroeder]

Say that I have code like:

# Original Code
unless defined?(value)
  value = 'default'
end

This is reported as a Style/IfUnlessModifier failure. If I autocorrect it, it changes to:

# Autocorrected Code
value = 'default' unless defined?(value)

If value isn't defined, the original code will set it to 'default' while the autocorrected code will set it to nil.

I usually try to avoid using defined? altogether. But the example above is similar to what I was seeing in some legacy code and I wanted to document it.

Often code like this can be rewritten to use ||=, as long a false value doesn't ever need to override the default. Or it could be rewritten to use an additional value_defined variable that is set before the assignment of value.

I'm not sure what an autocorrection could be for this situation. Maybe RuboCop shouldn't do anything here?

RuboCop version

$ [bundle exec] rubocop -V
1.36.0 (using Parser 3.1.2.1, rubocop-ast 1.21.0, running on ruby 3.0.3) [x86_64-darwin20]
  - rubocop-rails 2.16.1