class RubbyCop::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/rubbycop/cop/variable_force/variable.rb, line 17
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/rubbycop/cop/variable_force/variable.rb, line 81
def argument?
  ARGUMENT_DECLARATION_TYPES.include?(@declaration_node.type)
end
assign(node) click to toggle source
# File lib/rubbycop/cop/variable_force/variable.rb, line 33
def assign(node)
  @assignments << Assignment.new(node, self)
end
block_argument?() click to toggle source
# File lib/rubbycop/cop/variable_force/variable.rb, line 89
def block_argument?
  argument? && @scope.node.block_type?
end
capture_with_block!() click to toggle source
# File lib/rubbycop/cop/variable_force/variable.rb, line 61
def capture_with_block!
  @captured_by_block = true
end
explicit_block_local_variable?() click to toggle source
# File lib/rubbycop/cop/variable_force/variable.rb, line 97
def explicit_block_local_variable?
  @declaration_node.shadowarg_type?
end
keyword_argument?() click to toggle source
# File lib/rubbycop/cop/variable_force/variable.rb, line 93
def keyword_argument?
  %i[kwarg kwoptarg].include?(@declaration_node.type)
end
method_argument?() click to toggle source
# File lib/rubbycop/cop/variable_force/variable.rb, line 85
def method_argument?
  argument? && %i[def defs].include?(@scope.node.type)
end
reference!(node) click to toggle source
# File lib/rubbycop/cop/variable_force/variable.rb, line 41
def reference!(node)
  reference = Reference.new(node, @scope)
  @references << reference
  consumed_branches = Set.new

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

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

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

    unless assignment.branch.may_run_incompletely?
      consumed_branches << assignment.branch
    end
  end
end
referenced?() click to toggle source
# File lib/rubbycop/cop/variable_force/variable.rb, line 37
def referenced?
  !@references.empty?
end
should_be_unused?() click to toggle source
# File lib/rubbycop/cop/variable_force/variable.rb, line 77
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 and it means we cannot track the usage of the variable. So we consider it's used to suppress false positive offenses.

# File lib/rubbycop/cop/variable_force/variable.rb, line 73
def used?
  @captured_by_block || referenced?
end