class RuboCop::Cop::Style::InverseMethods
This cop check for usages of not (`not` or `!`) called on a method when an inverse of that method can be used instead. Methods that can be inverted by a not (`not` or `!`) should be defined in `InverseMethods` Methods that are inverted by inverting the return of the block that is passed to the method should be defined in `InverseBlocks`
@example
# bad !foo.none? !foo.any? { |f| f.even? } !foo.blank? !(foo == bar) foo.select { |f| !f.even? } foo.reject { |f| f != 7 } # good foo.none? foo.blank? foo.any? { |f| f.even? } foo != bar foo == bar !!('foo' =~ /^\w+$/) !(foo.class < Numeric) # Checking class hierarchy is allowed # Blocks with guard clauses are ignored: foo.select do |f| next if f.zero? f != 1 end
Constants
- CAMEL_CASE
- CLASS_COMPARISON_METHODS
- EQUALITY_METHODS
- MSG
- NEGATED_EQUALITY_METHODS
Public Class Methods
autocorrect_incompatible_with()
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# File lib/rubocop/cop/style/inverse_methods.rb, line 46 def self.autocorrect_incompatible_with [Style::Not] end
Public Instance Methods
autocorrect(node)
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# File lib/rubocop/cop/style/inverse_methods.rb, line 96 def autocorrect(node) method_call, _lhs, method, _rhs = inverse_candidate?(node) if method_call && method lambda do |corrector| corrector.remove(not_to_receiver(node, method_call)) corrector.replace(method_call.loc.selector, inverse_methods[method].to_s) if EQUALITY_METHODS.include?(method) corrector.remove(end_parentheses(node, method_call)) end end else correct_inverse_block(node) end end
correct_inverse_block(node)
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# File lib/rubocop/cop/style/inverse_methods.rb, line 114 def correct_inverse_block(node) method_call, method, block = inverse_block?(node) lambda do |corrector| corrector.replace(method_call.loc.selector, inverse_blocks[method].to_s) correct_inverse_selector(block, corrector) end end
correct_inverse_selector(block, corrector)
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# File lib/rubocop/cop/style/inverse_methods.rb, line 124 def correct_inverse_selector(block, corrector) selector = block.loc.selector.source if NEGATED_EQUALITY_METHODS.include?(selector.to_sym) selector[0] = '=' corrector.replace(block.loc.selector, selector) else if block.loc.dot range = dot_range(block.loc) corrector.remove(range) end corrector.remove(block.loc.selector) end end
on_block(node)
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# File lib/rubocop/cop/style/inverse_methods.rb, line 80 def on_block(node) inverse_block?(node) do |_method_call, method, block| return unless inverse_blocks.key?(method) return if negated?(node) && negated?(node.parent) return if node.each_node(:next).any? # Inverse method offenses inside of the block of an inverse method # offense, such as `y.reject { |key, _value| !(key =~ /c\d/) }`, # can cause auto-correction to apply improper corrections. ignore_node(block) add_offense(node, message: format(MSG, method: method, inverse: inverse_blocks[method])) end end
on_send(node)
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# File lib/rubocop/cop/style/inverse_methods.rb, line 66 def on_send(node) return if part_of_ignored_node?(node) inverse_candidate?(node) do |_method_call, lhs, method, rhs| return unless inverse_methods.key?(method) return if possible_class_hierarchy_check?(lhs, rhs, method) return if negated?(node) add_offense(node, message: format(MSG, method: method, inverse: inverse_methods[method])) end end
Private Instance Methods
camel_case_constant?(node)
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# File lib/rubocop/cop/style/inverse_methods.rb, line 177 def camel_case_constant?(node) node.const_type? && node.source =~ CAMEL_CASE end
dot_range(loc)
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# File lib/rubocop/cop/style/inverse_methods.rb, line 181 def dot_range(loc) range_between(loc.dot.begin_pos, loc.expression.end_pos) end
end_parentheses(node, method_call)
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# File lib/rubocop/cop/style/inverse_methods.rb, line 162 def end_parentheses(node, method_call) Parser::Source::Range.new(node.loc.expression.source_buffer, method_call.loc.expression.end_pos, node.loc.expression.end_pos) end
inverse_blocks()
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# File lib/rubocop/cop/style/inverse_methods.rb, line 147 def inverse_blocks @inverse_blocks ||= cop_config['InverseBlocks'] .merge(cop_config['InverseBlocks'].invert) end
inverse_methods()
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# File lib/rubocop/cop/style/inverse_methods.rb, line 142 def inverse_methods @inverse_methods ||= cop_config['InverseMethods'] .merge(cop_config['InverseMethods'].invert) end
negated?(node)
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# File lib/rubocop/cop/style/inverse_methods.rb, line 152 def negated?(node) node.parent.respond_to?(:method?) && node.parent.method?(:!) end
not_to_receiver(node, method_call)
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# File lib/rubocop/cop/style/inverse_methods.rb, line 156 def not_to_receiver(node, method_call) Parser::Source::Range.new(node.loc.expression.source_buffer, node.loc.selector.begin_pos, method_call.loc.expression.begin_pos) end
possible_class_hierarchy_check?(lhs, rhs, method)
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When comparing classes, `!(Integer < Numeric)` is not the same as `Integer > Numeric`.
# File lib/rubocop/cop/style/inverse_methods.rb, line 170 def possible_class_hierarchy_check?(lhs, rhs, method) CLASS_COMPARISON_METHODS.include?(method) && (camel_case_constant?(lhs) || (rhs.size == 1 && camel_case_constant?(rhs.first))) end