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# frozen_string_literal: true
module RuboCop
module Cop
module Performance
class ARCountEach < RuboCop::Cop::Cop
def message(ivar)
"If #{ivar} is AR relation, avoid `#{ivar}.count ...; #{ivar}.each... `, this will trigger two queries. " \
"Use `#{ivar}.load.size ...; #{ivar}.each... ` instead. If #{ivar} is an array, try to use #{ivar}.size."
end
def_node_matcher :count_match, <<~PATTERN
(send (ivar $_) :count)
PATTERN
def_node_matcher :each_match, <<~PATTERN
(send (ivar $_) :each)
PATTERN
def file_name(node)
node.location.expression.source_buffer.name
end
def in_haml_file?(node)
file_name(node).end_with?('.haml.rb')
end
def on_send(node)
return unless in_haml_file?(node)
ivar_count = count_match(node)
return unless ivar_count
node.each_ancestor(:begin) do |begin_node|
begin_node.each_descendant do |n|
ivar_each = each_match(n)
add_offense(node, location: :expression, message: message(ivar_count)) if ivar_each == ivar_count
end
end
end
end
end
end
end
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