ruby - 为什么 `ObjectSpace.count_objects`的对象总数没有变化？

Question

我得到了这个结果(参见 https://ruby-doc.org/core-2.5.1/ObjectSpace.html#method-c-count_objects ):

total = ObjectSpace.count_objects[:TOTAL]
new_object = "tonytonyjan"
ObjectSpace.count_objects[:TOTAL] - total  # => 0

total = ObjectSpace.count_objects[:T_STRING]
new_object = "tonytonyjan"
ObjectSpace.count_objects[:T_STRING] - total  # => 0

请解释为什么结果为零。 new_object 是否在初始化后就死掉了？

Answer 1

而是依靠each_object 来提供事件对象的状态:

def foo
  total = ObjectSpace.each_object(String).count
  str = "kiddorails"
  puts ObjectSpace.each_object(String).count - total
end

foo
#=> 1

另一件需要注意的事情:上面的代码片段并不能完全证明有关递增 String 对象的详细信息，因为 GC 已启用并且可以随时启动。我更喜欢这个:

def foo
  GC.enable # enables GC if not enabled
  GC.start(full_mark: true, immediate_sweep: true, immediate_mark: false) # perform GC if required on current object space
  GC.disable # disable GC to get the right facts below
  total = ObjectSpace.each_object(String).count
  100.times { "kiddorails" }
  puts ObjectSpace.each_object(String).count - total
end
foo #=> 100