Class: RuboCop::Cop::Lint::UselessSetterCall::MethodVariableTracker

Inherits:
Object
  • Object
show all
Defined in:
lib/rubocop/cop/lint/useless_setter_call.rb

Overview

This class tracks variable assignments in a method body and if a variable contains object passed as argument at the end of the method.

Instance Method Summary collapse

Constructor Details

#initialize(body_node) ⇒ MethodVariableTracker

Returns a new instance of MethodVariableTracker.



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# File 'lib/rubocop/cop/lint/useless_setter_call.rb', line 73

def initialize(body_node)
  @body_node = body_node
  @local = nil
end

Instance Method Details

#constructor?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/lint/useless_setter_call.rb', line 148

def constructor?(node)
  return true if node.literal?
  return false unless node.send_type?

  node.method?(:new)
end

#contain_local_object?(variable_name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/lint/useless_setter_call.rb', line 78

def contain_local_object?(variable_name)
  return @local[variable_name] if @local

  @local = {}

  scan(@body_node) { |node| process_assignment_node(node) }

  @local[variable_name]
end

#process_assignment(asgn_node, rhs_node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/useless_setter_call.rb', line 140

def process_assignment(asgn_node, rhs_node)
  @local[asgn_node.name] = if rhs_node.variable?
                             @local[rhs_node.name]
                           else
                             constructor?(rhs_node)
                           end
end

#process_assignment_node(node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/useless_setter_call.rb', line 96

def process_assignment_node(node)
  case node.type
  when :masgn
    process_multiple_assignment(node)
  when :or_asgn, :and_asgn
    process_logical_operator_assignment(node)
  when :op_asgn
    process_binary_operator_assignment(node)
  when *ASSIGNMENT_TYPES
    process_assignment(node, node.rhs) if node.rhs
  end
end

#process_binary_operator_assignment(op_asgn_node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/useless_setter_call.rb', line 131

def process_binary_operator_assignment(op_asgn_node)
  lhs_node = op_asgn_node.lhs
  return unless ASSIGNMENT_TYPES.include?(lhs_node.type)

  @local[lhs_node.name] = true

  throw :skip_children
end

#process_logical_operator_assignment(asgn_node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/useless_setter_call.rb', line 123

def process_logical_operator_assignment(asgn_node)
  return unless ASSIGNMENT_TYPES.include?(asgn_node.lhs.type)

  process_assignment(asgn_node.lhs, asgn_node.rhs)

  throw :skip_children
end

#process_multiple_assignment(masgn_node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/useless_setter_call.rb', line 109

def process_multiple_assignment(masgn_node)
  masgn_node.assignments.each_with_index do |lhs_node, index|
    next unless ASSIGNMENT_TYPES.include?(lhs_node.type)

    if masgn_node.rhs.array_type? && (rhs_node = masgn_node.rhs.children[index])
      process_assignment(lhs_node, rhs_node)
    else
      @local[lhs_node.name] = true
    end
  end

  throw :skip_children
end

#scan(node, &block) ⇒ Object 



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# File 'lib/rubocop/cop/lint/useless_setter_call.rb', line 88

def scan(node, &block)
  catch(:skip_children) do
    yield node

    node.each_child_node { |child_node| scan(child_node, &block) }
  end
end