55 lines
2 KiB
Ruby
55 lines
2 KiB
Ruby
module RuboCop
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module Cop
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module Gitlab
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class KeysFirstAndValuesFirst < RuboCop::Cop::Cop
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FIRST_PATTERN = /\Afirst\z/.freeze
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def message(used_method)
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<<~MSG
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Don't use `.keys.first` and `.values.first`.
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Instead use `.each_key.first` and `.each_value.first` (or `.first.first` and `first.second`)
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This will reduce memory usage and execution time.
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MSG
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end
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def on_send(node)
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if find_on_keys_or_values?(node)
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add_offense(node, location: :selector, message: message(node.method_name))
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end
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end
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def autocorrect(node)
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lambda do |corrector|
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replace_with = if node.descendants.first.method_name == :values
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'.each_value'
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elsif node.descendants.first.method_name == :keys
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'.each_key'
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else
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throw("Expect '.values.first' or '.keys.first', but get #{node.descendants.first.method_name}.first") # rubocop:disable Cop/BanCatchThrow
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end
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upto_including_keys_or_values = node.descendants.first.source_range
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before_keys_or_values = node.descendants[1].source_range
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range_to_replace = node.source_range
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.with(begin_pos: before_keys_or_values.end_pos,
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end_pos: upto_including_keys_or_values.end_pos)
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corrector.replace(range_to_replace, replace_with)
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end
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end
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def find_on_keys_or_values?(node)
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chained_on_node = node.descendants.first
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node.method_name.to_s =~ FIRST_PATTERN &&
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chained_on_node.is_a?(RuboCop::AST::SendNode) &&
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[:keys, :values].include?(chained_on_node.method_name) &&
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node.descendants[1]
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end
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def method_name_for_node(node)
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children[1].to_s
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end
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end
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end
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end
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end
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