What should be the value returned by a service?

service_return_value.rb

# A - only returns success true/false
module DocumentService
  class Create
    def self.call(a, b)
      if process_works?
        true
      else
        false
      end
    end
  end
end

# B - raise exception if fails, return something else (what?) if it works
module DocumentService
  class Create
    def self.call(a, b)
      raise NotFoundError if a.nil?
      
      a.whatever(b)
      a
    end
  end
end

# C - returns a tuple [status, result]
module DocumentService
  class Create
    def self.call(a, b)
      a.something(b)
      [:ok, a]
    rescue Exception => exception
      [:error, exception]
    end
  end
end

# D - returns nothing but provide methods to extract the result
module DocumentService
  class Create
    def call(a, b)
      @result = process(a,b)
    end
    
    def result
      @result
    end
    
    def success?
      @result.present?
    end
  end
end