关于WKWebview KVO的问题

最近听云上监听到一个crash，内容如下：

An instance 0x11c9d7400 of class WKWebView was deallocated while
 key value observers were still registered with it. 
Current observation info: 
<NSKeyValueObservationInfo 0x172a3b600> 
( <NSKeyValueObservance 0x170e498d0: 
Observer: 0x177231b20, Key path: load）

看一下崩溃路径，就是用户进入webView，然后点击返回按钮返回，就直接crash掉了。

截屏2021-06-02 下午12.09.44.png

但是我看到相应的VC中只有两个kvo，一个title的，一个estimatedProgress,根本就没有一个load相关的。然后我又搜遍了所有的webview相关的，也没有发现有一个load的监听。

后来找到了一种方法，可以打印webView观察者相关的信息

            id info = self.webView.observationInfo;
            id info1 = [info valueForKey:@"_observances"];
            id info2 = [info1 valueForKey:@"_property"];
            id info3 = [info2 valueForKey:@"_keyPath"];
            NSLog(@"====== 0 %@",info);
            NSLog(@"====== 1 %@",info1);
            NSLog(@"====== 2 %@",info2);
            NSLog(@"====== 3 %@",info3);

打印出来结果如下：

2021-06-02 12:17:39.440592+0800 shansong[13307:3766327] ====== 0 <NSKeyValueObservationInfo 0x2807fa5a0> (
<NSKeyValueObservance 0x281f0a070: Observer: 0x2807f01e0, Key path: loading, Options: <New: YES, Old: NO, Prior: NO> Context: 0x10b085000, Property: 0x281f09f20>
<NSKeyValueObservance 0x281f0a190: Observer: 0x107d18240, Key path: title, Options: <New: YES, Old: NO, Prior: NO> Context: 0x0, Property: 0x281f0a160>
<NSKeyValueObservance 0x281f0a2b0: Observer: 0x107d18240, Key path: estimatedProgress, Options: <New: NO, Old: NO, Prior: NO> Context: 0x105979f30, Property: 0x281f0a220>
)
2021-06-02 12:17:39.440724+0800 shansong[13307:3766327] ====== 1 (
    "<NSKeyValueObservance 0x281f0a070: Observer: 0x2807f01e0, Key path: loading, Options: <New: YES, Old: NO, Prior: NO> Context: 0x10b085000, Property: 0x281f09f20>",
    "<NSKeyValueObservance 0x281f0a190: Observer: 0x107d18240, Key path: title, Options: <New: YES, Old: NO, Prior: NO> Context: 0x0, Property: 0x281f0a160>",
    "<NSKeyValueObservance 0x281f0a2b0: Observer: 0x107d18240, Key path: estimatedProgress, Options: <New: NO, Old: NO, Prior: NO> Context: 0x105979f30, Property: 0x281f0a220>"
)
2021-06-02 12:17:39.440858+0800 shansong[13307:3766327] ====== 2 (
    "<NSKeyValueUnnestedProperty: Container class: DWKWebView, Key: loading, isa for autonotifying: NSKVONotifying_DWKWebView, Key paths of directly and indirectly affecting properties: none>",
    "<NSKeyValueUnnestedProperty: Container class: DWKWebView, Key: title, isa for autonotifying: NSKVONotifying_DWKWebView, Key paths of directly and indirectly affecting properties: none>",
    "<NSKeyValueUnnestedProperty: Container class: DWKWebView, Key: estimatedProgress, isa for autonotifying: NSKVONotifying_DWKWebView, Key paths of directly and indirectly affecting properties: none>"
)
2021-06-02 12:17:39.440908+0800 shansong[13307:3766327] ====== 3 (
    loading,
    title,
    estimatedProgress
)

然后发现这个loading的observer和我自己添加的两个不一样，于是查了下这个loading的class，

(lldb) p ((id)0x2807f01e0)->isa
(Class) $0 = NBSWKWebViewObserver

发现这个罪魁祸首，NBSWKWebViewObserver，NBS相关的就是听云的，后来我把项目的听云sdk删掉再运行就没有这个可恶的loading了。

后面，就是如何和听云相关的沟通了。