Exception mocking lambdas when running multiple test classes in jdk 11

Failure Information (for bugs)

When running tests on CI, an exception gets thrown when trying to create mock lambdas because a class definition already exists. As a temporary workaround, we have a JUnit test rule that will try to instantiate annotated mocks and retry if it catches an exception like so:

try {
  MockKAnnotations.init(target)
} catch (ex : MockKException) {
  unmockkAll() // This seems to fix the issue
  MockKAnnotations.init(target) // retry
}

But unfortunately this can’t account for the times where we are instantiating mocks inline without annotations. This was not happening so much when our CI was running on jdk 8 but we’re trying to upgrade to the latest CircleCI image.

Steps to Reproduce

Please provide detailed steps for reproducing the issue.

1. write a bunch of test classes that use mock lambdas, I’ve seen the exception thrown for lambdas with 0-2 arguments.
2. run them all together
3. overlapping tests might throw this exception.

Context

Please provide any relevant information about your setup. This is important in case the issue is not reproducible except for under certain conditions.

• MockK version: 1.11.0
• OS: android
• Kotlin version: 1.4.32
• JDK version: 11
• JUnit version: 4
• Type of test: unit test OR android instrumented test: unit/robolectric

Failure Logs

Please include any relevant log snippets or files here.

Stack trace

io.mockk.MockKException: Can't instantiate proxy for class kotlin.Function0
	at io.mockk.impl.instantiation.JvmMockFactory.newProxy(JvmMockFactory.kt:64)
	at io.mockk.impl.instantiation.AbstractMockFactory.newProxy$default(AbstractMockFactory.kt:29)
	at io.mockk.impl.instantiation.AbstractMockFactory.mockk(AbstractMockFactory.kt:59)
	at ***my test here***
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.runTestClass(JUnitTestClassExecutor.java:110)
	at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:58)
	at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:38)
	at org.gradle.api.internal.tasks.testing.junit.AbstractJUnitTestClassProcessor.processTestClass(AbstractJUnitTestClassProcessor.java:62)
	at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:51)
	at jdk.internal.reflect.GeneratedMethodAccessor159.invoke(Unknown Source)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
	at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:33)
	at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:94)
	at com.sun.proxy.$Proxy2.processTestClass(Unknown Source)
	at org.gradle.api.internal.tasks.testing.worker.TestWorker.processTestClass(TestWorker.java:119)
	at jdk.internal.reflect.GeneratedMethodAccessor158.invoke(Unknown Source)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
	at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:182)
	at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:164)
	at org.gradle.internal.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:414)
	at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64)
	at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:48)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:56)
	at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: io.mockk.proxy.MockKAgentException: Failed to subclass interface kotlin.jvm.functions.Function0
	at io.mockk.proxy.jvm.ProxyMaker.proxy(ProxyMaker.kt:38)
	at io.mockk.impl.instantiation.JvmMockFactory.newProxy(JvmMockFactory.kt:34)
	... 48 more
Caused by: java.lang.IllegalArgumentException: Could not create type
	at net.bytebuddy.TypeCache.findOrInsert(TypeCache.java:155)
	at net.bytebuddy.TypeCache.findOrInsert(TypeCache.java:175)
	at io.mockk.proxy.jvm.transformation.SubclassInstrumentation.subclass(SubclassInstrumentation.kt:51)
	at io.mockk.proxy.jvm.ProxyMaker.subclass(ProxyMaker.kt:113)
	at io.mockk.proxy.jvm.ProxyMaker.proxy(ProxyMaker.kt:35)
	... 49 more
Caused by: java.lang.IllegalStateException: Error invoking java.lang.invoke.MethodHandles$Lookup#defineClass
	at net.bytebuddy.dynamic.loading.ClassInjector$UsingLookup$Dispatcher$ForJava9CapableVm.defineClass(ClassInjector.java:1777)
	at net.bytebuddy.dynamic.loading.ClassInjector$UsingLookup.injectRaw(ClassInjector.java:1543)
	at net.bytebuddy.dynamic.loading.ClassInjector$AbstractBase.inject(ClassInjector.java:110)
	at net.bytebuddy.dynamic.loading.ClassLoadingStrategy$UsingLookup.load(ClassLoadingStrategy.java:492)
	at net.bytebuddy.dynamic.TypeResolutionStrategy$Passive.initialize(TypeResolutionStrategy.java:100)
	at net.bytebuddy.dynamic.DynamicType$Default$Unloaded.load(DynamicType.java:6292)
	at io.mockk.proxy.jvm.transformation.SubclassInstrumentation.doInterceptedSubclassing(SubclassInstrumentation.kt:98)
	at io.mockk.proxy.jvm.transformation.SubclassInstrumentation.access$doInterceptedSubclassing(SubclassInstrumentation.kt:21)
	at io.mockk.proxy.jvm.transformation.SubclassInstrumentation$subclass$1.call(SubclassInstrumentation.kt:54)
	at io.mockk.proxy.jvm.transformation.SubclassInstrumentation$subclass$1.call(SubclassInstrumentation.kt:21)
	at net.bytebuddy.TypeCache.findOrInsert(TypeCache.java:153)
	... 53 more
Caused by: java.lang.LinkageError: loader 'app' attempted duplicate class definition for kotlin.jvm.functions.Function0$Subclass3. (kotlin.jvm.functions.Function0$Subclass3 is in unnamed module of loader 'app')
	at java.base/java.lang.ClassLoader.defineClass1(Native Method)
	at java.base/java.lang.System$2.defineClass(System.java:2131)
	at java.base/java.lang.invoke.MethodHandles$Lookup.defineClass(MethodHandles.java:962)
	at java.base/jdk.internal.reflect.GeneratedMethodAccessor276.invoke(Unknown Source)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at net.bytebuddy.dynamic.loading.ClassInjector$UsingLookup$Dispatcher$ForJava9CapableVm.defineClass(ClassInjector.java:1773)
	... 63 more

[stale[bot]]

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[prakashparamasivam-rakuten]

I have similar issue https://github.com/mockk/mockk/issues/925