调试 - [NSCFDictionary setObject：forKey：]：尝试插入nil值 [英] Debugging -[NSCFDictionary setObject:forKey:]: attempt to insert nil value

问题描述

我已经对我的项目做了一些更改，现在我运行应用程序时收到以上消息，而不是如何调试它。
我已阅读 这里 ，我必须在 - [NSCFDictionary setObject：forKey：] 中设置一个断点，并设置一个条件。

I have done some changes to my project and now I am getting above message when running the app and don't how how to debug it. I have read here that I have to put a break point in -[NSCFDictionary setObject:forKey:] and set a condition as well.

但是，我如何设置他们提到的条件？ （仅当值为nil时停止）我在Xcode4上，并且只在尝试设置断点时获取此窗口。

But, how do I set the condition they mentioned? (Stop only when value is nil) I am on Xcode4 and only get this window when trying to set a breakpoint.

目前它停止在每个 - [NSCFDictionary setObject：forKey：] 这不是很有帮助，因为即使在正确的调用和苹果的内部调用也会停止（太多！）

Currently it stops at every -[NSCFDictionary setObject:forKey:] which is not very helpful since it will stop even in correct calls and Apple's internal calls as well (too many!)

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推荐答案

删除断点并添加异常断点。这将停止任何异常（如试图插入nil到字典）。对于所有调试会话，这是一个好的做法，即使是间歇性异常（这些难以找到的问题）将在调试器发生的时候被捕获。

Remove that breakpoint and add an Exception breakpoint. This will stop on any exception (like attempting to insert nil into a dictionary). It's good practice to leave this breakpoint on for all debugging sessions, that way even intermittent exceptions (those hard-to-find problems) will be caught in the debugger the moment they happen.

要添加异常断点，请单击断点列表底部的添加（+）按钮，然后单击添加异常断点。保持配置为原样。

To add an Exception breakpoint, click the Add (+) button at the bottom of the breakpoints list and click Add Exception Breakpoint. Leave it configured as-is.

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