Android Espresso multidex fail

Question

We use multidex in our app for a long time but recently with latest update it fails on android API <19 e.g. emulator with api 16 It is standard java.lang.NoClassDefFoundError.

If I define multidexKeepProguard for missing class e.g. java.lang.NoClassDefFoundError. rx.plugins.RxJavaHooks exception

-keep class rx.plugins.**{*;}

then it will just fail in a different place with the same reason NoClassDefFound

Here is the runner, app and manifest setup:

https://gist.github.com/originx/1890599b57b0ee3e14a85a4732301cd9

Logcat:

https://gist.github.com/originx/887f80d405334f1903b3024eb5cd1024

Build enviroment setup:

Android Studio 2.2.2 Build #AI-145.3360264, built on October 18, 2016 JRE: 1.8.0_112-release-b05 x86_64 JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o

Compile options

compile 'com.android.support:multidex:1.0.1'

build tools info:

   classpath 'com.android.tools.build:gradle:2.2.2'
   compileSdkVersion 25
   buildToolsVersion '25'


   defaultConfig {
        applicationId "app.packagename.com"

         minSdkVersion 16
        targetSdkVersion 25

        testInstrumentationRunner "de.payback.app.CustomAndroidJUnitRunner"
        multiDexEnabled true
    }

 dexOptions {
        jumboMode true
        preDexLibraries false
        javaMaxHeapSize "4g"
        maxProcessCount = 8
    }

  debug {
            applicationIdSuffix '.debug'
            versionNameSuffix '-debug'
            signingConfig signingConfigs.debug
            minifyEnabled false
            shrinkResources debugShrinkResourcesEnabled
            proguardFiles getDefaultProguardFile('proguard-android.txt'), '../proguardRules/proguard-rules.pro', '../proguardRules/proguard-debug-rules.pro'
          //  multiDexKeepProguard file('../proguardRules/multidex-proguard.pro')
            testProguardFiles getDefaultProguardFile('proguard-android.txt'), '../proguardRules/proguard-rules.pro', '../proguardRules/proguard-debug-test-rules.pro'
            testCoverageEnabled false
        }
        release {
            minifyEnabled true
            shrinkResources true
            testProguardFiles getDefaultProguardFile('proguard-android.txt'), '../proguardRules/proguard-rules.pro'
            proguardFiles getDefaultProguardFile('proguard-android.txt'), '../proguardRules/proguard-rules.pro'
          //  multiDexKeepProguard file('../proguardRules/multidex-proguard.pro')
        }

I tried everything from extending MultiDexApplication, to custom MultiDex.install(context) to using MultiDexRunner

same results always

if using multidexkeepproguard file for classes which are usually not found then they are in main dex file but of course something else is missing which indicates that multidex was not properly installed and initialized

Google bug report:

https://code.google.com/p/android/issues/detail?id=228449

repo to reproduce the issue can be found here:

https://github.com/originx/multidex/tree/master

To run please disable instant run

To reproduce multidex issue please run following command

./gradlew clean connectedPayGermanyCompatDebugAndroidTest

run on any device or API 16 emulator Tests on GTI8190 4.1.2 failed Instrumentation run failed due to java.lang.NoClassDefFoundError

Any suggestions how to work around this until I get more info from the Google team?

Answer 1

Explanation by Google dev:

The issue is that the rx.plugins.RxJavaHooks class referenced from the CustomJunitRunner.onCreate() method is in the secondary dex file of the main app, and you are accessing it before the class loaders get fully patched.

When the main application and test code share a dependency, we will remove it from the test's dependencies (as we expect it to be available in the main application). However, with legacy multidex, this is causing problems.

Currently, there are 2 workarounds:

Option 1 Ensure the rx.plugins.RxJavaHooks is in the main dex by creating a file multidexKeepProguard.pro and adding "-keep class rx.plugins.**"

Option 2 Remove references to RxJavaHooks from onCreate(), and move them to onStart() (not sure if this accomplishes when you want though): @Override public void onStart() { super.onStart(); //hook up schedulers to rxjava so espresso idling resouces can fetch it properly RxJavaHooks.setOnComputationScheduler(current -> Schedulers.from(AsyncTask.THREAD_POOL_EXECUTOR)); RxJavaHooks.setOnIOScheduler(current -> Schedulers.from(AsyncTask.THREAD_POOL_EXECUTOR)); RxJavaHooks.setOnNewThreadScheduler(current -> Schedulers.from(AsyncTask.THREAD_POOL_EXECUTOR)); }

Solution

Workaround

So current workaround would be either use multidexKeepProguard.pro file and in your debug config point to that file:

 debug {
            applicationIdSuffix '.debug'
            multiDexKeepProguard file('../proguardRules/multidex-proguard.pro')
        }

Your multidex proguard file should contain classes which are not being found in the main dex file, in my case it was RxJavaPlugin, so my multidexproguard file contains:

-keep class rx.** { *; }