class RuboCop::Cop::Style::RedundantInitialize
Checks for ‘initialize` methods that are redundant.
An initializer is redundant if it does not do anything, or if it only calls ‘super` with the same arguments given to it. If the initializer takes an argument that accepts multiple values (`restarg`, `kwrestarg`, etc.) it will not register an offense, because it allows the initializer to take a different number of arguments as its superclass potentially does.
NOTE: If an initializer argument has a default value, RuboCop
assumes it to not be redundant.
NOTE: Empty initializers are registered as offenses, but it is possible to purposely create an empty ‘initialize` method to override a superclass’s initializer.
@safety
This cop is unsafe because if subclass overrides `initialize` method with a different arity than superclass.
@example
# bad def initialize end # bad def initialize super end # bad def initialize(a, b) super end # bad def initialize(a, b) super(a, b) end # good def initialize do_something end # good def initialize do_something super end # good (different number of parameters) def initialize(a, b) super(a) end # good (default value) def initialize(a, b = 5) super end # good (default value) def initialize(a, b: 5) super end # good (changes the parameter requirements) def initialize(*) end # good (changes the parameter requirements) def initialize(**) end # good (changes the parameter requirements) def initialize(...) end
@example AllowComments: true (default)
# good def initialize # Overriding to negate superclass `initialize` method. end
@example AllowComments: false
# bad def initialize # Overriding to negate superclass `initialize` method. end
Constants
- MSG
- MSG_EMPTY
Public Instance Methods
on_def(node)
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# File lib/rubocop/cop/style/redundant_initialize.rb, line 110 def on_def(node) return if acceptable?(node) if node.body.nil? register_offense(node, MSG_EMPTY) else return if node.body.begin_type? if (args, super_node = initialize_forwards?(node)) return unless same_args?(super_node, args) register_offense(node, MSG) end end end
Private Instance Methods
acceptable?(node)
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# File lib/rubocop/cop/style/redundant_initialize.rb, line 134 def acceptable?(node) !node.method?(:initialize) || forwards?(node) || allow_comments?(node) end
allow_comments?(node)
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# File lib/rubocop/cop/style/redundant_initialize.rb, line 142 def allow_comments?(node) return false unless cop_config['AllowComments'] contains_comments?(node) && !comments_contain_disables?(node, name) end
forwards?(node)
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# File lib/rubocop/cop/style/redundant_initialize.rb, line 138 def forwards?(node) node.arguments.each_child_node(:restarg, :kwrestarg, :forward_args, :forward_arg).any? end
register_offense(node, message)
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# File lib/rubocop/cop/style/redundant_initialize.rb, line 128 def register_offense(node, message) add_offense(node, message: message) do |corrector| corrector.remove(range_by_whole_lines(node.source_range, include_final_newline: true)) end end
same_args?(super_node, args)
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# File lib/rubocop/cop/style/redundant_initialize.rb, line 148 def same_args?(super_node, args) return true if super_node.zsuper_type? args.map(&:name) == super_node.arguments.map { |a| a.children[0] } end