HighFile-scopeRuby Plug & play

Avoid Using Global Variables

Check for global variable usage (e.g., variables prefixed with `$`). Suggest using instance variables, constants, or dependency injection instead.

Why this matters

Global variables create hidden dependencies, making code harder to debug, maintain, and test. Use instance variables or constants instead.

Side-by-side examples engineers can pattern-match during review.

Avoid

$counter = 0

def increment
  $counter += 1
end

Prefer

class Counter
  def initialize
    @counter = 0
  end

  def increment
    @counter += 1
  end
end

Bad

$counter = 0

def increment
  $counter += 1
end

Good

class Counter
  def initialize
    @counter = 0
  end

  def increment
    @counter += 1
  end
end

From the same buckets as this rule.

Critical
Avoid Duplicating String Literals
Store repeated string literals in constants or variables to improve maintainability and reduce redundancy.
duplication-complexitymaintainability
Critical
Avoid Empty Methods
Detect methods that have an empty body. If a method is empty, ensure that a comment is present explaining why it remains unimplemented.
maintainabilityreadability-refactor
Critical
Avoid modifying built-in prototypes
Detect modifications to built-in prototypes. Modifying built-in objects can lead to compatibility issues and unexpected behavior. Recommend creating helper functions instead.
maintainabilitysecurity-hardening