Monkey Patch Core Type (ARCH6197)

Key ruby.quality.monkey-patch-core · Severity warning · Category quality

Reopening core classes like String, Array, or Hash to add methods is fragile global mutation; it can clash with other libraries and cause surprising behaviour app-wide.

Incorrect

class String
  def shout
    upcase + "!"
  end
end

"hello".shout

Correct

module StringExtensions
  refine String do
    def shout
      upcase + "!"
    end
  end
end

using StringExtensions
"hello".shout

Fix

Use a helper method, a wrapper class, or a scoped refine instead of mutating the core class globally.