Lint-UnreachableLoop.md

Pattern: Unreachable loop

Issue: -

Description

This rule checks for loops that will have at most one iteration.

A loop that can never reach the second iteration is a possible error in the code. In rare cases where only one iteration (or at most one iteration) is intended behavior, the code should be refactored to use if conditionals.

Examples

# bad
while node
  do_something(node)
  node = node.parent
  break
end

# good
while node
  do_something(node)
  node = node.parent
end

# bad
def verify_list(head)
  item = head
  begin
    if verify(item)
      return true
    else
      return false
    end
  end while(item)
end

# good
def verify_list(head)
  item = head
  begin
    if verify(item)
      item = item.next
    else
      return false
    end
  end while(item)

  true
end

# bad
def find_something(items)
  items.each do |item|
    if something?(item)
      return item
    else
      raise NotFoundError
    end
  end
end

# good
def find_something(items)
  items.each do |item|
    if something?(item)
      return item
    end
  end
  raise NotFoundError
end

Further Reading

• RuboCop - Lint/UnreachableLoop