"failed to access class androidx.lifecycle.LiveData$ObserverWrapper" error in 1.12.1 when stubbing LiveData in test with AndroidJUnit4 runner

[gekylafas]

After upgrading from 1.12.0 to 1.12.1 the following sample test fails:

package io.mockk.test.livedata

import androidx.lifecycle.LiveData
import androidx.test.ext.junit.runners.AndroidJUnit4
import io.mockk.every
import io.mockk.mockk
import org.junit.Test
import org.junit.runner.RunWith

@RunWith(AndroidJUnit4::class)
class MockkLiveDataTest {
    interface VM {
        val liveData: LiveData<String>
    }

    @Test
    fun `liveData is stubbed successfully`() {
        val vm = mockk<VM>()
        every { vm.liveData } returns mockk()
    }
}

I managed to git bisect the problem and the first bad commit was 62d5c79.

Error output

failed to access class androidx.lifecycle.LiveData$ObserverWrapper from class androidx.lifecycle.LiveData$Subclass1 (androidx.lifecycle.LiveData$ObserverWrapper is in unnamed module of loader org.robolectric.internal.AndroidSandbox$SdkSandboxClassLoader @55a304e4; androidx.lifecycle.LiveData$Subclass1 is in unnamed module of loader net.bytebuddy.dynamic.loading.MultipleParentClassLoader @7cc4c5c3)
java.lang.IllegalAccessError: failed to access class androidx.lifecycle.LiveData$ObserverWrapper from class androidx.lifecycle.LiveData$Subclass1 (androidx.lifecycle.LiveData$ObserverWrapper is in unnamed module of loader org.robolectric.internal.AndroidSandbox$SdkSandboxClassLoader @55a304e4; androidx.lifecycle.LiveData$Subclass1 is in unnamed module of loader net.bytebuddy.dynamic.loading.MultipleParentClassLoader @7cc4c5c3)
	at androidx.lifecycle.LiveData$Subclass1.<clinit>(Unknown Source)
	at jdk.internal.reflect.GeneratedSerializationConstructorAccessor9.newInstance(Unknown Source)
	at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
	at org.objenesis.instantiator.sun.SunReflectionFactoryInstantiator.newInstance(SunReflectionFactoryInstantiator.java:48)
	at io.mockk.proxy.jvm.ObjenesisInstantiator.instanceViaObjenesis(ObjenesisInstantiator.kt:75)
	at io.mockk.proxy.jvm.ObjenesisInstantiator.instantiateViaProxy(ObjenesisInstantiator.kt:66)
	at io.mockk.proxy.jvm.ObjenesisInstantiator.instance(ObjenesisInstantiator.kt:29)
	at io.mockk.proxy.jvm.ProxyMaker.instantiate(ProxyMaker.kt:75)
	at io.mockk.proxy.jvm.ProxyMaker.proxy(ProxyMaker.kt:42)
	at io.mockk.impl.instantiation.JvmMockFactory.newProxy(JvmMockFactory.kt:34)
	at io.mockk.impl.instantiation.AbstractMockFactory.newProxy$default(AbstractMockFactory.kt:29)
	at io.mockk.impl.instantiation.AbstractMockFactory.temporaryMock(AbstractMockFactory.kt:127)
	at io.mockk.impl.recording.states.RecordingState$call$retValue$1.invoke(RecordingState.kt:72)
	at io.mockk.impl.instantiation.JvmAnyValueGenerator$anyValue$2.invoke(JvmAnyValueGenerator.kt:35)
	at io.mockk.impl.instantiation.AnyValueGenerator.anyValue(AnyValueGenerator.kt:34)
	at io.mockk.impl.instantiation.JvmAnyValueGenerator.anyValue(JvmAnyValueGenerator.kt:31)
	at io.mockk.impl.recording.states.RecordingState.call(RecordingState.kt:70)
	at io.mockk.impl.recording.CommonCallRecorder.call(CommonCallRecorder.kt:53)
	at io.mockk.impl.stub.MockKStub.handleInvocation(MockKStub.kt:266)
	at io.mockk.impl.instantiation.JvmMockFactoryHelper$mockHandler$1.invocation(JvmMockFactoryHelper.kt:23)
	at io.mockk.proxy.jvm.advice.Interceptor.call(Interceptor.kt:21)
	at io.mockk.proxy.jvm.advice.BaseAdvice.handle(BaseAdvice.kt:42)
	at io.mockk.proxy.jvm.advice.jvm.JvmMockKProxyInterceptor.interceptNoSuper(JvmMockKProxyInterceptor.java:45)
	...
	at org.robolectric.RobolectricTestRunner$HelperTestRunner$1.evaluate(RobolectricTestRunner.java:591)
	at org.robolectric.internal.SandboxTestRunner$2.lambda$evaluate$0(SandboxTestRunner.java:274)
	at org.robolectric.internal.bytecode.Sandbox.lambda$runOnMainThread$0(Sandbox.java:88)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:834)

[gekylafas]

Any updates on this, anyone?

[gekylafas]

This still happens in 1.12.2

[jairrab]

Also running into the same issue on 1.12.1 and 1.12.2

[kingargyle]

This issue resurface, and Robolectric has some findings, robolectric/robolectric#5871

[kingargyle]

Unfortunately they are saying the Mockk will probably need to fix it... we are tossing the hot potatoe again.

[hoisie]

I did a git bisect and this is the commit that introduced the regression: 62d5c79

[gekylafas]

Yeap, exactly the commit I found when git bisecting.
Unfortunately, no response so far from mockk maintainer(s).

[Raibaz]

Thanks for bisecting and investigating this.

Since the commit you mention was introduced to fix #280 and the comments in that issue mention a workaround, I may consider reverting it.

I'd be more than happy to review a PR with it, actually.

[hoisie]

I put up #782 which fixes it from the Robolectric side.

[Raibaz]

Awesome, thanks a lot!

[hoisie]

@Raibaz I would be interested in capturing this issue, and perhaps a couple of other basic Robolectric + MockK integrations, in a test case. Would a new directory such as client-tests/robolectric be appropriate?

[Raibaz]

Sure, that'd be perfect, and thanks a lot for doing this!

[kingargyle]

@Raibaz is there a timeline for a release with this fix?

[ILikeYourHat]

@Raibaz When this fix will be released? We cannot downgrade MockK to 1.12.0 due to some other bug that was fixed in 1.12.1 😢

[Raibaz]

I'm planning on putting a release out sometime next week, sorry but this week's a pretty busy one :(

[ILikeYourHat]

@Raibaz bump 🙂

[Raibaz]

Sorry about this, v1.12.3 just came out :)