功能需求：使用UIImagePickerController选择图片，然后上传。
环境：iPhoneSE，iOS 11.1.2（15B202），手机的照片启用了iCloud照片图库，选中了优化iPhone存储空间，如下图

截屏

代码：

let imgPVc = UIImagePickerController()

func showPhotoContrller(library:Bool) {
    self.imgPVc.delegate = self
    self.imgPVc.allowsEditing = true
    self.imgPVc.mediaTypes = [kUTTypeImage as String]
    self.imgPVc.modalPresentationStyle = .fullScreen
    if library {
        self.imgPVc.sourceType = .photoLibrary
    }
    else {
        self.imgPVc.sourceType = .camera
    }
    if #available(iOS 11.0, *) {
        self.imgPVc.imageExportPreset = .current
    }
    
    self.viewController?.present(self.imgPVc, animated: true, completion: nil)
}

回调

extension CHPhotoNative: UIImagePickerControllerDelegate,UINavigationControllerDelegate {
    @objc func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
        qlog(message: "pick photo finish \n\(info)")
        self.imgPVc.dismiss(animated: true, completion: nil)
        let tmpUserHeader = NSTemporaryDirectory().appending("/tmpuserheader.jpg")
        if let img = info[UIImagePickerControllerEditedImage] as? UIImage {
            if let imgData = imgDataFromUIImage(img: img) as NSData? {
                try? imgData.write(toFile: tmpUserHeader, options: .atomicWrite)
                self.callJs(jsFuncName: callback, data: tmpUserHeader)
                return
            }
        }
        self.callJs(jsFuncName: callback, data: nil)
    }
    
    public func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        qlog(message: "pick photo cancel")
        self.callJs(jsFuncName: self.callback, data: nil)
        self.imgPVc.dismiss(animated: true, completion: nil)
    }
}

异常：选中照片的时候会从iCloud下载照片，然后进入编辑界面，在编辑界面点击“选取”，控制台就打印错误信息，并且app的界面不能再操作。打印信息如下，回调没有执行，程序没有crash，但是界面不可再操作。

2018-12-05 15:30:54.988544+0800 EuropeAIHome[33081:16424558] [general] <NSXPCConnection: 0x1c030d6e0> connection from pid 33097: Warning: Exception caught during invocation of received message, dropping incoming message and invalidating the connection.
Exception: *** -[NSURL URLByAppendingPathExtension:]: component, components, or pathExtension cannot be nil.
*** -[NSURL URLByAppendingPathExtension:]: component, components, or pathExtension cannot be nil.
(
    0   CoreFoundation                      0x0000000185371d1c <redacted> + 148
    1   libobjc.A.dylib                     0x00000001845c0528 objc_exception_throw + 56
    2   CoreFoundation                      0x0000000185371c4c <redacted> + 0
    3   Foundation                          0x0000000185d8491c <redacted> + 92
    4   PhotosUI                            0x0000000198287928 <redacted> + 1660
    5   PhotosUI                            0x0000000198286db4 <redacted> + 36
    6   Foundation                          0x0000000185e871e0 <redacted> + 20
    7   Foundation                          0x0000000185e8597c <redacted> + 2632
    8   Foundation                          0x0000000185c5c830 <redacted> + 240
    9   libxpc.dylib                        0x0000000184fd67d0 <redacted> + 68
    10  libxpc.dylib                        0x0000000184fd4168 <redacted> + 984
    11  libdispatch.dylib                   0x0000000104d0552c _dispatch_client_callout4 + 16
    12  libdispatch.dylib                   0x0000000104d08f58 _dispatch_mach_msg_invoke + 380
    13  libdispatch.dylib                   0x0000000104d13f30 _dispatch_queue_serial_drain + 212
    14  libdispatch.dylib                   0x0000000104d084c0 _dispatch_mach_invoke + 992
    15  libdispatch.dylib                   0x0000000104d13f30 _dispatch_queue_serial_drain + 212
    16  libdispatch.dylib                   0x0000000104d089a4 _dispatch_queue_invoke + 332
    17  libdispatch.dylib                   0x0000000104d15104 _dispatch_root_queue_drain_deferred_wlh + 424
    18  libdispatch.dylib                   0x0000000104d1c100 _dispatch_workloop_worker_thread + 652
    19  libsystem_pthread.dylib             0x0000000184f9afd0 _pthread_wqthread + 932
    20  libsystem_pthread.dylib             0x0000000184f9ac20 start_wqthread + 4
)

根据打印信息可以得知，之所以报错，是因为NSURL的URLByAppendingPathExtension方法的参数为nil导致的，但是这个界面是苹果的，我们没有办法修改，怎么办呢；
鄙人的解决方法是，使用runtime机制，替换NSURL的URLByAppendingPathExtension方法，在新方法中判断参数是否为nil，代码如下（代码基于swift4，OC的话，就可以用load方法替换initializeMethod方法，详情请搜索iOS Swizzling）

extension NSURL {
    public class func initializeMethod() {
        DispatchQueue.once(token: "NSURL.initializeMethod") {
            if let m1 = class_getInstanceMethod(self, #selector(NSURL.appendingPathExtension)) {
                method_exchangeImplementations(m1, class_getInstanceMethod(self, #selector(ex_URLByAppendingPathExtension(component:)))!);
            }
        }
    }
    
    @objc func ex_URLByAppendingPathExtension(component:String?) {
        if let com = component {
            self.ex_URLByAppendingPathExtension(component: com)
        }
    }
}

swift 没有DispatchQueue.once方法，添加一个extension来实现该功能。

extension DispatchQueue {
    private static var onceTracker = [String]()
    
    open class func once(token: String, block:() -> Void) {
        objc_sync_enter(self)
        defer { objc_sync_exit(self) }
        
        if onceTracker.contains(token) {
            return
        }
        
        onceTracker.append(token)
        block()
    }
}

这样子之后，就可以看到，当选中图片之后，ex_URLByAppendingPathExtension方法的参数确实为nil，这样处理之后，app就可以继续运行，但是可能会有新的打印信息。

2018-12-05 15:58:05.871301+0800 EuropeAIHome[33216:16440651] [Generic] -[PUPhotoPickerExtensionHostContext _UIImagePickerControllerInfoDictionaryFromPhotoPickerInfoDictionary:] Unable to copy from file:///var/mobile/Media/PhotoData/CPLAssets/group173/DFA0B171-1286-428F-95D8-692ACC515759.JPG to file:///private/var/mobile/Containers/Data/Application/3ABF885C-332D-45BC-B151-1ACA6D8D0538/tmp/9C8CD5C9-74B7-4EE7-99A3-F02EDDFC55F2 Error Domain=NSCocoaErrorDomain Code=260 "未能打开文件“DFA0B171-1286-428F-95D8-692ACC515759.JPG”，因为它不存在。" UserInfo={NSFilePath=/var/mobile/Media/PhotoData/CPLAssets/group173/DFA0B171-1286-428F-95D8-692ACC515759.JPG, NSUnderlyingError=0x1c564e160 {Error Domain=NSPOSIXErrorDomain Code=2 "No such file or directory"}}
2018-12-05 15:58:05.873+0800 CHPhotoNative.swift[imagePickerController(_:didFinishPickingMediaWithInfo:):89] pick photo finish 
["UIImagePickerControllerCropRect": NSRect: {{0, 316}, {2303.9998901367239, 2305}}, "UIImagePickerControllerImageURL": file:///private/var/mobile/Containers/Data/Application/3ABF885C-332D-45BC-B151-1ACA6D8D0538/tmp/9C8CD5C9-74B7-4EE7-99A3-F02EDDFC55F2, "UIImagePickerControllerPHAsset": <PHAsset: 0x1511675d0> E07D54CC-593E-4CB3-9E13-357943927F56/L0/001 mediaType=1/0, sourceType=1, (3024x4032), creationDate=2018-07-01 03:38:21 +0000, location=1, hidden=0, favorite=0 , "UIImagePickerControllerEditedImage": <UIImage: 0x1c46b2720> size {638, 640} orientation 0 scale 1.000000, "UIImagePickerControllerMediaType": public.image, "UIImagePickerControllerReferenceURL": assets-library://asset/asset.JPG?id=E07D54CC-593E-4CB3-9E13-357943927F56&ext=JPG]

但是这个并不影响图片的使用，info的UIImagePickerControllerEditedImagekey的value然后可以获取到编辑后的图片，UIImagePickerControllerPHAsset的value也仍然有数据。