init应该在self init上分配，还是测试相等？ [英] Should init be assigning, or testing equality, on self init?

问题描述

我从 https://github.com/facebook/facebook-ios-sdk .git ，并注意到代码中有两个这样的结构：

 （id）init {
 if（（self == [super init]））{
 ... 
} 
} 
  

我希望 self 被分配到这里，没有测试平等：

{pre> （id）init {
if（（self = [super init]））{
...
}



或至少：

 （id）init {
 self = [super init]; 
 if（self）{
 ... 
} 
} 
  

这是在 src / FBDialog.m 和 sample / Hackbook / Hackbook / DataSet.m 之内。

（抱歉，如果这应该在错误跟踪器;无法找到实际提交的任何方法...： - /

解决方案

应该分配自己，因为 [super init] 可能会返回与self不同的对象。 p>

通常正常检查是否正常工作，但不需要工作，您应该始终分配。

我相信，在这种特殊情况下使用 == 时，最近版本的cl ang甚至会发出警告。

I cloned from https://github.com/facebook/facebook-ios-sdk.git today, and noticed two spots in the code which have this construct:

(id) init {
    if ((self == [super init])) {
        ...
    }
}

I would expect self to be assigned here, not tested for equality:

(id) init {
    if ((self = [super init])) {
        ...
    }
}

or at the very least:

(id) init {
    self = [super init];
    if (self) {
        ...
    }
}

This is within src/FBDialog.m and sample/Hackbook/Hackbook/DataSet.m.

(Sorry if this should be in the bug tracker instead; couldn't find a way to actually submit anything there... :-/

解决方案

It should assign self, because [super init] may return a different object than self.

Checking for equality will often work but isn't required to work. You should always assign.

I believe that recent versions of clang even emit warnings when using == in this particular case.

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