Class: RuboCop::Cop::VariableForce::Variable

Inherits:
Object
  • Object
show all
Defined in:
lib/rubocop/cop/variable_force/variable.rb

Overview

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

Constant Summary collapse

VARIABLE_DECLARATION_TYPES = 
(VARIABLE_ASSIGNMENT_TYPES + ARGUMENT_DECLARATION_TYPES).freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, declaration_node, scope) ⇒ Variable 



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# File 'lib/rubocop/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

Instance Attribute Details

#assignments ⇒ Object (readonly)

Returns the value of attribute assignments.



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# File 'lib/rubocop/cop/variable_force/variable.rb', line 13

def assignments
  @assignments
end

#captured_by_block ⇒ Object (readonly) Also known as: captured_by_block?

Returns the value of attribute captured_by_block.



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# File 'lib/rubocop/cop/variable_force/variable.rb', line 13

def captured_by_block
  @captured_by_block
end

#declaration_node ⇒ Object (readonly)

Returns the value of attribute declaration_node.



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# File 'lib/rubocop/cop/variable_force/variable.rb', line 13

def declaration_node
  @declaration_node
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/rubocop/cop/variable_force/variable.rb', line 13

def name
  @name
end

#references ⇒ Object (readonly)

Returns the value of attribute references.



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# File 'lib/rubocop/cop/variable_force/variable.rb', line 13

def references
  @references
end

#scope ⇒ Object (readonly)

Returns the value of attribute scope.



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# File 'lib/rubocop/cop/variable_force/variable.rb', line 13

def scope
  @scope
end

Instance Method Details

#argument? ⇒ Boolean 



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# File 'lib/rubocop/cop/variable_force/variable.rb', line 81

def argument?
  ARGUMENT_DECLARATION_TYPES.include?(@declaration_node.type)
end

#assign(node) ⇒ Object 



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# File 'lib/rubocop/cop/variable_force/variable.rb', line 33

def assign(node)
  @assignments << Assignment.new(node, self)
end

#block_argument? ⇒ Boolean 



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# File 'lib/rubocop/cop/variable_force/variable.rb', line 89

def block_argument?
  argument? && @scope.node.block_type?
end

#capture_with_block! ⇒ Object 



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# File 'lib/rubocop/cop/variable_force/variable.rb', line 61

def capture_with_block!
  @captured_by_block = true
end

#explicit_block_local_variable? ⇒ Boolean 



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# File 'lib/rubocop/cop/variable_force/variable.rb', line 97

def explicit_block_local_variable?
  @declaration_node.shadowarg_type?
end

#keyword_argument? ⇒ Boolean 



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# File 'lib/rubocop/cop/variable_force/variable.rb', line 93

def keyword_argument?
  %i[kwarg kwoptarg].include?(@declaration_node.type)
end

#method_argument? ⇒ Boolean 



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# File 'lib/rubocop/cop/variable_force/variable.rb', line 85

def method_argument?
  argument? && %i[def defs].include?(@scope.node.type)
end

#reference!(node) ⇒ Object 



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# File 'lib/rubocop/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!(node)
    end

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

    unless assignment.branch.may_run_incompletely?
      consumed_branches << assignment.branch
    end
  end
end

#referenced? ⇒ Boolean 



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# File 'lib/rubocop/cop/variable_force/variable.rb', line 37

def referenced?
  !@references.empty?
end

#should_be_unused? ⇒ Boolean 



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# File 'lib/rubocop/cop/variable_force/variable.rb', line 77

def should_be_unused?
  name.to_s.start_with?('_')
end

#used? ⇒ Boolean

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.



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# File 'lib/rubocop/cop/variable_force/variable.rb', line 73

def used?
  @captured_by_block || referenced?
end