如果我们启用僵尸对象，所有弱引用都会被清零吗?

问题描述

通常，如果一个对象被释放，所有弱引用都将被清除.

如果我们启用僵尸对象呢?

产品 -> 编辑方案 -> 启用僵尸对象

弱引用也会被清零吗?

否则正常情况下不会出现的bug会出现在enable僵尸对象上

我强烈怀疑，正如其中一个答案所说，弱引用将被清除.

话虽如此，

如何修复当 UIViewController 已经消失时调用 viewDidScroll 的错误? 并在那里回答建议.

解决方案

即使启用了 Zombie Objects，弱引用也会被设置为 nil.

我是这样测试的:

id __weak o;@autoreleasepool {id ob = [[NSObject alloc] init];o = ob;NSLog(@"发布前弱引用 %@", o);}NSLog(@"发布后弱引用 %@", o);

无论是否启用 Zombies，都会发生相同的输出:

2013-12-05 23:55:35.571 WeakPointers [93840:303] 发布前弱参考2013-12-05 23:55:35.572 WeakPointers[93840:303] 发布后弱引用(空)

Normally, if an object deallocated, all weak references will be nilled.

What about if we enable zombie object?

Product -> Edit Scheme -> Enable Zombie Object

Will weak references be nilled too?

Otherwise, bugs that won't happen on normal circumstances will happen on enable zombie object

I strongly suspected, as one of the answer says, that weak references will be nilled.

That being said,

How to fix the bug where viewDidScroll is called when UIViewController is already gone? and answer there suggest otherwise.

解决方案

The weak reference will be set to nil even if you enable Zombie Objects.

I tested it like this:

id __weak o;
@autoreleasepool {
    id ob = [[NSObject alloc] init];
    o = ob;
    NSLog(@"Weak ref before release %@", o);
}
NSLog(@"Weak ref after release %@", o);

With Zombies enabled or not, the same output happens:

2013-12-05 23:55:35.571 WeakPointers[93840:303] Weak ref before release
2013-12-05 23:55:35.572 WeakPointers[93840:303] Weak ref after release (null)

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