Hello, I’ve issue with SwiftUI’s preview when usin...

# koin

[Raymond Chan]

Hello, I’ve issue with SwiftUI’s preview when using Koin, it crashes all the time when startKoin is invoked.

The setup is:

KoinHelper.kt

fun initKoin3() {
    startKoin {
    }
}

AScreen.swift

struct AScreen_Previews: PreviewProvider {
    static var previews: some View {
        let a = KoinHelperIosKt.doInitKoin3()
        AScreen()
    }
}

Crash log

Thread 0 Crashed::  Dispatch queue: BSXPCCnx:com.apple.dt.xcode-previews.systemservices (BSCnx:client:com.apple.dt.uv.agent-preview-scene-service)
0   libsystem_kernel.dylib        	       0x1af2060cc __pthread_kill + 8
1   libsystem_pthread.dylib       	       0x1af25a1e8 pthread_kill + 256
2   libsystem_c.dylib             	       0x180129eb0 __abort + 124
3   libsystem_c.dylib             	       0x180129e34 abort + 136
4   shared                        	       0x1060db608 konan::abort() + 12
5   shared                        	       0x106108528 (anonymous namespace)::terminateWithUnhandledException(ObjHeader*)::$_1::operator()() const + 16
6   shared                        	       0x106108340 void (anonymous namespace)::$_0::operator()<(anonymous namespace)::terminateWithUnhandledException(ObjHeader*)::$_1>((anonymous namespace)::terminateWithUnhandledException(ObjHeader*)::$_1) + 80
7   shared                        	       0x106108050 (anonymous namespace)::terminateWithUnhandledException(ObjHeader*) + 12
8   shared                        	       0x10610800c (anonymous namespace)::processUnhandledException(ObjHeader*) + 64
9   shared                        	       0x10611c710 kotlin::ProcessUnhandledException(ObjHeader*) + 188
10  shared                        	       0x10611f288 Kotlin_ObjCExport_trapOnUndeclaredException + 36
11  shared                        	       0x1060cefc8 objc2kotlin_kfun:com.pfp.app.di#initKoin3(){} + 200 (/<compiler-generated>:1)
12  SplashScreen.1.preview-thunk.dylib	       0x11041cde0 static AScreen_Previews.__preview__previews.getter + 64 (SplashScreen.swift:50)
13  iosApp                        	       0x1026f3378 protocol witness for static PreviewProvider.previews.getter in conformance AScreen_Previews + 12
14  SwiftUI                       	       0x10ba49e68 0x10b0ec000 + 9821800
15  iosApp                        	       0x1026f33bc protocol witness for static _PreviewProvider._previews.getter in conformance AScreen_Previews + 40

Here is the full crash log:

iosApp-2023-03-17-152645.ips

[Raymond Chan]

problem solved, it’s because `doInitKoin`was invoked more than 1 time

[Isak Hansson]

Can you show how you solved it? Struggling with the same issue.

[Raymond Chan]

check your implementation in iOSApp.swift & DefaultAppObservable.swift as swift’s preview provider will execute the App class. we end up put doInitKoin into App.init()