Xcode project keeps crashing after converting to Swift 4, "Class implemented in both..."

Question

I recently converted an Xcode project to Swift 4. I fixed all the syntax errors. However, my app now crashes, after outputting an error message which starts
Class MPExportableArtworkProperties is implemented in both...

I have been looking around S/O but all I find is that its related to MapBox which I don't even have in my project/podfile. Can it have something to do with the regular map-kit? It crashes the app when I open the tab with my map, so I'm guessing that's where the problem is.

Full error message, formatted for readability:

objc[24634]: Class MPExportableArtworkProperties is implemented in both

/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/Library/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/MediaPlaybackCore.framework/MediaPlaybackCore
(0x126b1b108) and

/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/Library/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/MediaPlayer.framework/MediaPlayer
(0x1258107d0).

One of the two will be used. Which one is undefined.
This is the plowerthingscontroller saying that you are logged in
libc++abi.dylib: terminating with uncaught exception of type
NSException

its crashing and its the only error message i get so i feel like that have to be why, worked fine util i transformed it to swift 4 — Jonathan Nairn, Dec 28 '17 at 09:52
Must read this post [libc++abi.dylib: terminating with uncaught exception of type NSException (lldb)](https://stackoverflow.com/a/27389647/6822622) — AshvinGudaliya, Dec 28 '17 at 10:13
You could play around with the build settings and try and specify one or none of those to link to. — Jordan, Feb 01 '18 at 21:44

score 0 · Answer 1 · answered Mar 26 '18 at 05:19

I had this exact error, and in the end found it was due to something completely different: a circular dependency. Consider:

class DependencyManager {

    static let shared = DependencyManager()
    let aDependency: SomeDependency

    init() {

        aDependency = SomeDependency()
    }

    func resolve() -> SomeProtocol {
        // Create the actual class
        return 0
    }
}

where SomeDependency requires SomeProtocol

class SomeDependency {

    let x: SomeProtocol

    // Me trying to be clever and auto-inject the dependency
    init(x: SomeProtocol = DependencyManager.shared.resolve()) {
        self.x = x
    }
}

So when you first access DependencyManager.shared it tries instantiate SomeDependency, which requires DependencyManager.shared to already be instantiated.

I have no idea why MPExportableArtworkProperties is mentioned in the error, however cleaning up the code fixed the issue for me.

Xcode project keeps crashing after converting to Swift 4, "Class implemented in both..."

1 Answers1