module RuboCop::Cop::Metrics::Utils::RepeatedAttributeDiscount
@api private
Identifies repetitions `{c}send` calls with no arguments:
foo.bar foo.bar # => repeated foo.bar.baz.qux # => inner send repeated foo.bar.baz.other # => both inner send repeated foo.bar(2) # => not repeated
It also invalidates sequences if a receiver is reassigned:
xx.foo.bar xx.foo.baz # => inner send repeated self.xx = any # => invalidates everything so far xx.foo.baz # => no repetition self.xx.foo.baz # => all repeated
Constants
- VAR_SETTER_TO_GETTER
Public Class Methods
new(node, discount_repeated_attributes: false)
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Plug into the calculator
Calls superclass method
# File lib/rubocop/cop/metrics/utils/repeated_attribute_discount.rb, line 30 def initialize(node, discount_repeated_attributes: false) super(node) return unless discount_repeated_attributes self_attributes = {} # Share hash for `(send nil? :foo)` and `(send (self) :foo)` @known_attributes = { s(:self) => self_attributes, nil => self_attributes } # example after running `obj = foo.bar; obj.baz.qux` # { nil => {foo: {bar: {}}}, # s(self) => same hash ^, # s(:lvar, :obj) => {baz: {qux: {}}} # } end
Public Instance Methods
calculate_node(node)
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Calls superclass method
# File lib/rubocop/cop/metrics/utils/repeated_attribute_discount.rb, line 53 def calculate_node(node) update_repeated_attribute(node) if discount_repeated_attributes? super end
discount_repeated_attributes?()
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# File lib/rubocop/cop/metrics/utils/repeated_attribute_discount.rb, line 43 def discount_repeated_attributes? defined?(@known_attributes) end
evaluate_branch_nodes(node)
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Calls superclass method
# File lib/rubocop/cop/metrics/utils/repeated_attribute_discount.rb, line 47 def evaluate_branch_nodes(node) return if discount_repeated_attributes? && discount_repeated_attribute?(node) super end
Private Instance Methods
discount_repeated_attribute?(send_node)
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# File lib/rubocop/cop/metrics/utils/repeated_attribute_discount.rb, line 66 def discount_repeated_attribute?(send_node) return false unless attribute_call?(send_node) repeated = true find_attributes(send_node) do |hash, lookup| return false if hash.nil? repeated = false hash[lookup] = {} end repeated end
find_attributes(node) { |nil| ... }
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Returns the “known_attributes” for the `node` by walking the receiver tree If at any step the subdirectory does not exist, it is yielded with the associated key (method_name) If the node is not a series of `©send` calls with no arguments, then `nil` is yielded
# File lib/rubocop/cop/metrics/utils/repeated_attribute_discount.rb, line 103 def find_attributes(node, &block) if attribute_call?(node) calls = find_attributes(node.receiver, &block) value = node.method_name elsif root_node?(node) calls = @known_attributes value = node else return yield nil end calls.fetch(value) { yield [calls, value] } end
setter_to_getter(node)
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@returns `[receiver, method | nil]` for the given setter `node` or `nil` if it is not a setter.
# File lib/rubocop/cop/metrics/utils/repeated_attribute_discount.rb, line 126 def setter_to_getter(node) if (type = VAR_SETTER_TO_GETTER[node.type]) # (lvasgn :my_var (int 42)) => [(lvar my_var), nil] [s(type, node.children.first), nil] elsif node.shorthand_asgn? # (or-asgn (send _receiver :foo) _value) # (or-asgn (send _receiver :foo) _value) => [_receiver, :foo] node.children.first.children elsif node.respond_to?(:setter_method?) && node.setter_method? # (send _receiver :foo= (int 42) ) => [_receiver, :foo] method_name = node.method_name[0...-1].to_sym [node.receiver, method_name] end end
update_repeated_attribute(node)
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# File lib/rubocop/cop/metrics/utils/repeated_attribute_discount.rb, line 80 def update_repeated_attribute(node) return unless (receiver, method = setter_to_getter(node)) calls = find_attributes(receiver) { return } if method # e.g. `self.foo = 42` calls.delete(method) else # e.g. `var = 42` calls.clear end end