class RuboCop::Cop::VariableForce::Variable

A Variable represents existence of a local variable. This holds a variable declaration node and some states of the variable.

Constants

VARIABLE_DECLARATION_TYPES

Attributes

assignments[R]
captured_by_block[R]
captured_by_block?[R]
declaration_node[R]
name[R]
references[R]
scope[R]

Public Class Methods

new(name, declaration_node, scope) click to toggle source
# File lib/rubocop/cop/variable_force/variable.rb, line 15
def initialize(name, declaration_node, scope)
  unless VARIABLE_DECLARATION_TYPES.include?(declaration_node.type)
    raise ArgumentError,
          "Node type must be any of #{VARIABLE_DECLARATION_TYPES}, " \
          "passed #{declaration_node.type}"
  end

  @name = name.to_sym
  @declaration_node = declaration_node
  @scope = scope

  @assignments = []
  @references = []
  @captured_by_block = false
end

Public Instance Methods

argument?() click to toggle source
# File lib/rubocop/cop/variable_force/variable.rb, line 92
def argument?
  ARGUMENT_DECLARATION_TYPES.include?(@declaration_node.type)
end
assign(node) click to toggle source
# File lib/rubocop/cop/variable_force/variable.rb, line 31
def assign(node)
  @assignments << Assignment.new(node, self)
end
block_argument?() click to toggle source
# File lib/rubocop/cop/variable_force/variable.rb, line 100
def block_argument?
  argument? && @scope.node.block_type?
end
capture_with_block!() click to toggle source
# File lib/rubocop/cop/variable_force/variable.rb, line 72
def capture_with_block!
  @captured_by_block = true
end
explicit_block_local_variable?() click to toggle source
# File lib/rubocop/cop/variable_force/variable.rb, line 108
def explicit_block_local_variable?
  @declaration_node.shadowarg_type?
end
in_modifier_if?(assignment) click to toggle source

rubocop:enable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity

# File lib/rubocop/cop/variable_force/variable.rb, line 66
def in_modifier_if?(assignment)
  parent = assignment.node.parent
  parent = parent.parent if parent&.begin_type?
  parent&.if_type? && parent&.modifier_form?
end
keyword_argument?() click to toggle source
# File lib/rubocop/cop/variable_force/variable.rb, line 104
def keyword_argument?
  %i[kwarg kwoptarg].include?(@declaration_node.type)
end
method_argument?() click to toggle source
# File lib/rubocop/cop/variable_force/variable.rb, line 96
def method_argument?
  argument? && %i[def defs].include?(@scope.node.type)
end
reference!(node) click to toggle source

rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity

# File lib/rubocop/cop/variable_force/variable.rb, line 40
def reference!(node)
  reference = Reference.new(node, @scope)
  @references << reference
  consumed_branches = nil

  @assignments.reverse_each do |assignment|
    next if consumed_branches&.include?(assignment.branch)

    assignment.reference!(node) unless assignment.run_exclusively_with?(reference)

    # Modifier if/unless conditions are special. Assignments made in
    # them do not put the assigned variable in scope to the left of the
    # if/unless keyword. A preceding assignment is needed to put the
    # variable in scope. For this reason we skip to the next assignment
    # here.
    next if in_modifier_if?(assignment)

    break if !assignment.branch || assignment.branch == reference.branch

    unless assignment.branch.may_run_incompletely?
      (consumed_branches ||= Set.new) << assignment.branch
    end
  end
end
referenced?() click to toggle source
# File lib/rubocop/cop/variable_force/variable.rb, line 35
def referenced?
  !@references.empty?
end
should_be_unused?() click to toggle source
# File lib/rubocop/cop/variable_force/variable.rb, line 88
def should_be_unused?
  name.to_s.start_with?('_')
end
used?() click to toggle source

This is a convenient way to check whether the variable is used in its entire variable lifetime. For more precise usage check, refer Assignment#used?.

Once the variable is captured by a block, we have no idea when, where, and how many times the block would be invoked. This means we cannot track the usage of the variable. So we consider it's used to suppress false positive offenses.

# File lib/rubocop/cop/variable_force/variable.rb, line 84
def used?
  @captured_by_block || referenced?
end