Class: RuboCop::Cop::GraphQL::Overfetch

# File 'lib/rubocop/cop/graphql/overfetch.rb', line 19

def investigate(processed_source)
  erb = File.read(processed_source.buffer.name)
  query, = ::GraphQL::Client::ViewModule.extract_graphql_section(erb)
  return unless query

  aliases = {}
  fields = {}
  ranges = {}

  # TODO: Use GraphQL client parser
  document = ::GraphQL.parse(query.gsub(/::/, "__"))

  visitor = ::GraphQL::Language::Visitor.new(document)
  visitor[::GraphQL::Language::Nodes::Field] << ->(node, _parent) do
    name = node.alias || node.name
    fields[name] ||= 0
    field_aliases(name).each { |n| (aliases[n] ||= []) << name }
    ranges[name] ||= source_range(processed_source.buffer, node.line, 0)
  end
  visitor.visit

  send_methods(processed_source.ast).each do |node|
    method_names = method_names_for(*node)

    method_names.each do |method_name|
      aliases.fetch(method_name, []).each do |field_name|
        fields[field_name] += 1
      end
    end
  end

  fields.each do |field, count|
    next if count > 0
    add_offense(nil, location: ranges[field], message: "GraphQL field '#{field}' query but was not used in template.")
  end
end

# File 'lib/rubocop/cop/graphql/overfetch.rb', line 68

def method_names_for(*node)
  receiver, method_name, *_args = node
  method_names = []

  method_names << method_name if method_name

  # add field accesses like `nodes.map(&:field)`
  method_names.concat(receiver.children) if receiver && receiver.sym_type?

  method_names.map!(&:to_s)
end