Ionic/Angular bootstrapping twice, works in debug.apk but not on release

Question

I am not that deep in Angular or Ionic. May be it comes. But for now I've the following Problem.

I have an Ionic App " ApplicationLatest ". This should start, do some initial checks and fine. But if this checks failes, it should completly switch over/failover to a separate " ApplicationOld ".

ApplicationLatest in main.ts :

        platformBrowserDynamic().bootstrapModule(AppModuleLatest)
            .catch(
              err => console.log(err)
            );

AppModuleLatest -> bootstrap: [AppComponent]

About an Emitter during the initial checks I trigger the possible failover

    this.parameterLoadError = this.initCheckup.routeError.subscribe((err) => {
    
        platformBrowserDynamic().bootstrapModule(AppModuleOld)
            .catch(
              err => console.log(err)
            );

    });

This works fine if I create the debug.apk

=> ionic cordova run android

But when I run the release

=> ionic cordova run android --prod --release

and run the app with a forced failover I got :

ERROR Error: A platform with a different configuration has been created. Please destroy it first.

But if I do the destroyPlatform(); before bootstrapping the AppModuleOld the screen keeps blank/white.

And an exception is thrown (which I capture with logcat)

09-25 09:24:02.052 20628 20628 D SystemWebChromeClient: http://localhost/main-es2015.9887f0567239099d41e3.js: Line 1 : ERROR Error: Uncaught (in promise): Error: No NgModule metadata found for 'od'.
09-25 09:24:02.052 20628 20628 D SystemWebChromeClient: Error: No NgModule metadata found for 'od'.
09-25 09:24:02.052 20628 20628 D SystemWebChromeClient:     at Gu.resolve (http://localhost/main-es2015.9887f0567239099d41e3.js:1:469088)
09-25 09:24:02.052 20628 20628 D SystemWebChromeClient:     at Nu.getNgModuleMetadata (http://localhost/main-es2015.9887f0567239099d41e3.js:1:454054)
09-25 09:24:02.052 20628 20628 D SystemWebChromeClient:     at Sh._loadModules (http://localhost/main-es2015.9887f0567239099d41e3.js:1:498940)
09-25 09:24:02.052 20628 20628 D SystemWebChromeClient:     at Sh._compileModuleAndComponents (http://localhost/main-es2015.9887f0567239099d41e3.js:1:498616)
09-25 09:24:02.052 20628 20628 D SystemWebChromeClient:     at Sh.compileModuleAsync (http://localhost/main-es2015.9887f0567239099d41e3.js:1:497741)
09-25 09:24:02.052 20628 20628 D SystemWebChromeClient:     at useClass.compileModuleAsync (http://localhost/main-es2015.9887f0567239099d41e3.js:1:509629)
09-25 09:24:02.052 20628 20628 D SystemWebChromeClient:     at zo (http://localhost/main-es2015.9887f0567239099d41e3.js:1:136755)
09-25 09:24:02.052 20628 20628 D SystemWebChromeClient:     at Qo.bootstrapModule (http://localhost/main-es2015.9887f0567239099d41e3.js:1:138680)
09-25 09:24:02.052 20628 20628 D SystemWebChromeClient:     at ld.initFailover (http://localhost/main-es2015.9887f0567239099d41e3.js:1:529186)
09-25 09:24:02.052 20628 20628 D SystemWebChromeClient:     at http://localhost/main-es2015.9887f0567239099d41e3.js:1:529730

There are so many questions in my head...

• Why can it run in debug.apk?
• But generally : Is such a failover possible?

Thanks for any hints and advice!

ionic --version
6.5.0

Angular CLI: 8.3.23
Node: 10.15.3
OS: linux x64
Angular: 8.2.13

Answer 1

With a little help of some good friends we found a working solutions.

Remember the initialted platfrom

    const platformRef = platformBrowserDynamic();
    platformRef.bootstrapModule(AppModuleLatest)
        .catch(
          err => console.log(err)
    );

During Failover, take the platformRef, destroy only that one.

    this.parameterLoadError = this.initCheckup.routeError.subscribe((err) => {
        // Destroy the old one
        platformRef.destroy();
        //bstrap a new one
        platformBrowserDynamic().bootstrapModule(AppModuleOld)
            .catch(
              err => console.log(err)
            );

    });

Also I have had to change the following params in angular.json

              "buildOptimizer": false,
              "aot": false,
              "outputHashing": "none",

It's working for me. On Desktop and (Android) mobile.