class RuboCop::Cop::Lint::LiteralAsCondition

Checks for literals used as the conditions or as operands in and/or expressions serving as the conditions of if/while/until/case-when/case-in.

NOTE: Literals in ‘case-in` condition where the match variable is used in `in` are accepted as a pattern matching.

@example

# bad
if 20
  do_something
end

# bad
if some_var && true
  do_something
end

# good
if some_var && some_condition
  do_something
end

# good
# When using a boolean value for an infinite loop.
while true
  break if condition
end

Constants

MSG

Public Instance Methods

message(node) click to toggle source
# File lib/rubocop/cop/lint/literal_as_condition.rb, line 93
def message(node)
  format(MSG, literal: node.source)
end
on_case(case_node) click to toggle source
# File lib/rubocop/cop/lint/literal_as_condition.rb, line 58
def on_case(case_node)
  if case_node.condition
    check_case(case_node)
  else
    case_node.each_when do |when_node|
      next unless when_node.conditions.all?(&:literal?)

      range = when_conditions_range(when_node)
      message = message(range)

      add_offense(range, message: message)
    end
  end
end
on_case_match(case_match_node) click to toggle source
# File lib/rubocop/cop/lint/literal_as_condition.rb, line 73
def on_case_match(case_match_node)
  if case_match_node.condition
    return if case_match_node.descendants.any?(&:match_var_type?)

    check_case(case_match_node)
  else
    case_match_node.each_in_pattern do |in_pattern_node|
      next unless in_pattern_node.condition.literal?

      add_offense(in_pattern_node)
    end
  end
end
on_if(node) click to toggle source
# File lib/rubocop/cop/lint/literal_as_condition.rb, line 40
def on_if(node)
  check_for_literal(node)
end
on_send(node) click to toggle source
# File lib/rubocop/cop/lint/literal_as_condition.rb, line 87
def on_send(node)
  return unless node.negation_method?

  check_for_literal(node)
end
on_until(node) click to toggle source
# File lib/rubocop/cop/lint/literal_as_condition.rb, line 51
def on_until(node)
  return if condition(node).false_type?

  check_for_literal(node)
end
Also aliased as: on_until_post
on_until_post(node)
Alias for: on_until
on_while(node) click to toggle source
# File lib/rubocop/cop/lint/literal_as_condition.rb, line 44
def on_while(node)
  return if condition(node).true_type?

  check_for_literal(node)
end
Also aliased as: on_while_post
on_while_post(node)
Alias for: on_while

Private Instance Methods

basic_literal?(node) click to toggle source
# File lib/rubocop/cop/lint/literal_as_condition.rb, line 108
def basic_literal?(node)
  if node.array_type?
    primitive_array?(node)
  else
    node.basic_literal?
  end
end
check_case(case_node) click to toggle source
# File lib/rubocop/cop/lint/literal_as_condition.rb, line 138
def check_case(case_node)
  condition = case_node.condition

  return if condition.array_type? && !primitive_array?(condition)
  return if condition.dstr_type?

  handle_node(condition)
end
check_for_literal(node) click to toggle source
# File lib/rubocop/cop/lint/literal_as_condition.rb, line 99
def check_for_literal(node)
  cond = condition(node)
  if cond.literal?
    add_offense(cond)
  else
    check_node(cond)
  end
end
check_node(node) click to toggle source
# File lib/rubocop/cop/lint/literal_as_condition.rb, line 120
def check_node(node)
  if node.send_type? && node.prefix_bang?
    handle_node(node.receiver)
  elsif node.operator_keyword?
    node.each_child_node { |op| handle_node(op) }
  elsif node.begin_type? && node.children.one?
    handle_node(node.children.first)
  end
end
condition(node) click to toggle source
# File lib/rubocop/cop/lint/literal_as_condition.rb, line 147
def condition(node)
  if node.send_type?
    node.receiver
  else
    node.condition
  end
end
handle_node(node) click to toggle source
# File lib/rubocop/cop/lint/literal_as_condition.rb, line 130
def handle_node(node)
  if node.literal?
    add_offense(node)
  elsif %i[send and or begin].include?(node.type)
    check_node(node)
  end
end
primitive_array?(node) click to toggle source
# File lib/rubocop/cop/lint/literal_as_condition.rb, line 116
def primitive_array?(node)
  node.children.all? { |n| basic_literal?(n) }
end
when_conditions_range(when_node) click to toggle source
# File lib/rubocop/cop/lint/literal_as_condition.rb, line 155
def when_conditions_range(when_node)
  range_between(
    when_node.conditions.first.source_range.begin_pos,
    when_node.conditions.last.source_range.end_pos
  )
end