Python GC 会处理这样的引用循环吗?

问题描述

使用默认情况下是启用的，应该是能够释放该结构，如果它的任何组件都无法从外部访问 并且它们没有 __del__() 方法.

如果这样做，垃圾收集器将不会 释放它们 因为它无法确定运行这些 __del__() 方法的安全顺序.

Using objgraph, I found a bunch of objects like this:

Will Python's garbage collector deal with cycles like this, or will it leak?

A slightly wider view of the loop:

解决方案

Python's standard reference counting mechanism cannot free cycles, so the structure in your example would leak.

The supplemental garbage collection facility, however, is enabled by default and should be able to free that structure, if none of its components are reachable from the outside anymore and they do not have __del__() methods.

If they do, the garbage collector will not free them because it cannot determine a safe order to run these __del__() methods.