React Native - app crashes with custom build type

Question

I've got a react native application, that works fine in Android, in debug and release build types. I want to add a new build type called releaseStaging, so I'm adding this to the app/build.gradle:

android: {
    buildTypes: {
        releaseStaging {
            resValue "string", "CodePushDeploymentKey", '"**something**"'
            matchingFallbacks = ['release']
            signingConfig signingConfigs.release
            minifyEnabled enableProguardInReleaseBuilds
            proguardFiles getDefaultProguardFile("proguard-android.txt"), "proguard-rules.pro"
        }
        ... debug and release defined here ...
    }
}

I've purposely named the build type "releaseStaging" because from reading around I can see that the react.gradle file does certain things based on the build type containing the word "release".

When I do:

npx react-native run-android --variant=releaseStaging

It builds OK and deploys to the device I'm testing on, but it just crashes on start.

On looking at logcat, I can see that the error is:

2022-01-26 12:26:00.494 4038-4102/? E/AndroidRuntime: FATAL EXCEPTION: create_react_context
    Process: com.myapp, PID: 4038
    java.lang.UnsatisfiedLinkError: couldn't find DSO to load: libhermes.so
        SoSource 0: com.facebook.soloader.ApkSoSource[root = /data/data/com.mediaburst.timetastic/lib-main flags = 1]
        SoSource 1: com.facebook.soloader.DirectorySoSource[root = /data/app/com.mediaburst.timetastic-jFpmTXGDULHlB6h75bUGQA==/lib/arm64 flags = 0]
        SoSource 2: com.facebook.soloader.DirectorySoSource[root = /vendor/lib64 flags = 2]
        SoSource 3: com.facebook.soloader.DirectorySoSource[root = /system/lib64 flags = 2]
        Native lib dir: /data/app/com.mediaburst.timetastic-jFpmTXGDULHlB6h75bUGQA==/lib/arm64
     result: 0
        at com.facebook.soloader.SoLoader.doLoadLibraryBySoName(SoLoader.java:918)
        at com.facebook.soloader.SoLoader.loadLibraryBySoNameImpl(SoLoader.java:740)
        at com.facebook.soloader.SoLoader.loadLibraryBySoName(SoLoader.java:654)
        at com.facebook.soloader.SoLoader.loadLibrary(SoLoader.java:634)
        at com.facebook.soloader.SoLoader.loadLibrary(SoLoader.java:582)
        at com.facebook.hermes.reactexecutor.HermesExecutor.<clinit>(HermesExecutor.java:20)
        at com.facebook.hermes.reactexecutor.HermesExecutorFactory.create(HermesExecutorFactory.java:29)
        at com.facebook.react.ReactInstanceManager$5.run(ReactInstanceManager.java:1066)
        at java.lang.Thread.run(Thread.java:919)

Answer 1

This problem occurs if your app has enableHermes flag set to true

I did not find it documented anywhere, but the solution would be to extend the code like following:

if (enableHermes) {
    def hermesPath = "../../node_modules/hermes-engine/android/";
    debugImplementation files(hermesPath + "hermes-debug.aar")
    releaseStagingImplementation files(hermesPath + "hermes-debug.aar") // Add this line
    releaseImplementation files(hermesPath + "hermes-release.aar")
} else {
    implementation jscFlavor
}

I'm not sure if it should be releaseStagingImplementation or releasestagingImplementation, so try with one or the other.

This tells the Gradle to include Hermes libraries in releaseStaging build type.