java.lang.NullPointerException: Cannot invoke "kotlinx.coroutines.flow.Flow.collect when bumping up coroutines 1.6.4 to 1.8.1

[IvanSanchez-uam]

I'm trying to bump up coroutines 1.6.4 and many issues come up when bumping up from versions 1.6.4 to 1.8.1, I have tried to change runTest { } to runBlocking { } as mentioned here and this workaround but neither of them worked.

Kotlin: 1.9.23
androidGradle: 8.3.2

java.lang.NullPointerException: Cannot invoke "kotlinx.coroutines.flow.Flow.collect(kotlinx.coroutines.flow.FlowCollector, kotlin.coroutines.Continuation)" at com.x.y.z.oneclickfareupgrade.OneClickFareUpgradeViewModel$initFlightsJourneySummaryLoaded$1.invokeSuspend(OneClickFareUpgradeViewModel.kt:232) at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33) at kotlinx.coroutines.internal.DispatchedContinuationKt.resumeCancellableWith(DispatchedContinuation.kt:363) at kotlinx.coroutines.intrinsics.CancellableKt.startCoroutineCancellable(Cancellable.kt:26) at kotlinx.coroutines.intrinsics.CancellableKt.startCoroutineCancellable$default(Cancellable.kt:21) at kotlinx.coroutines.CoroutineStart.invoke(CoroutineStart.kt:88) at kotlinx.coroutines.AbstractCoroutine.start(AbstractCoroutine.kt:123) at kotlinx.coroutines.BuildersKt__Builders_commonKt.launch(Builders.common.kt:52) at kotlinx.coroutines.BuildersKt.launch(Unknown Source) at kotlinx.coroutines.BuildersKt__Builders_commonKt.launch$default(Builders.common.kt:43) at kotlinx.coroutines.BuildersKt.launch$default(Unknown Source) at com.x.y.z.oneclickfareupgrade.OneClickFareUpgradeViewModel.initFlightsJourneySummaryLoaded$flights_productionDebug(OneClickFareUpgradeViewModel.kt:218) at com.x.y.z.flightsinfosite.journeysummary.FlightsJourneySummaryLoadedKt$FlightsJourneySummaryLoaded$1.invokeSuspend(FlightsJourneySummaryLoaded.kt:22) at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33) at androidx.compose.ui.test.ApplyingContinuationInterceptor$SendApplyContinuation.resumeWith(ApplyingContinuationInterceptor.kt:65) at androidx.compose.ui.test.FrameDeferringContinuationInterceptor$TrampolinedTask.resume(FrameDeferringContinuationInterceptor.kt:137) at androidx.compose.ui.test.FrameDeferringContinuationInterceptor.runWithoutResumingCoroutines(FrameDeferringContinuationInterceptor.kt:75) at androidx.compose.ui.test.TestMonotonicFrameClock.performFrame(TestMonotonicFrameClock.jvm.kt:132) at androidx.compose.ui.test.TestMonotonicFrameClock.access$performFrame(TestMonotonicFrameClock.jvm.kt:53) at androidx.compose.ui.test.TestMonotonicFrameClock$withFrameNanos$2$1$2.invokeSuspend(TestMonotonicFrameClock.jvm.kt:110) at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33) at kotlinx.coroutines.DispatchedTaskKt.resume(DispatchedTask.kt:231) at kotlinx.coroutines.DispatchedTaskKt.dispatch(DispatchedTask.kt:164) at kotlinx.coroutines.CancellableContinuationImpl.dispatchResume(CancellableContinuationImpl.kt:466) at kotlinx.coroutines.CancellableContinuationImpl.resumeImpl(CancellableContinuationImpl.kt:500) at kotlinx.coroutines.CancellableContinuationImpl.resumeImpl$default(CancellableContinuationImpl.kt:489) at kotlinx.coroutines.CancellableContinuationImpl.resumeUndispatched(CancellableContinuationImpl.kt:587) at kotlinx.coroutines.test.CancellableContinuationRunnable.run(TestDispatcher.kt:60) at kotlinx.coroutines.test.TestDispatcher.processEvent$kotlinx_coroutines_test(TestDispatcher.kt:24) at kotlinx.coroutines.test.TestCoroutineScheduler.runCurrent(TestCoroutineScheduler.kt:132) at androidx.compose.ui.test.junit4.AbstractMainTestClock$advanceDispatcher$1.invoke(AbstractMainTestClock.kt:74) at androidx.compose.ui.test.junit4.AbstractMainTestClock$advanceDispatcher$1.invoke(AbstractMainTestClock.kt:67) at androidx.compose.ui.test.junit4.AndroidSynchronization_androidKt.runOnUiThread(AndroidSynchronization.android.kt:33) at androidx.compose.ui.test.junit4.MainTestClockImpl$1.invoke(MainTestClockImpl.android.kt:32) at androidx.compose.ui.test.junit4.MainTestClockImpl$1.invoke(MainTestClockImpl.android.kt:32) at androidx.compose.ui.test.junit4.AbstractMainTestClock.advanceDispatcher(AbstractMainTestClock.kt:67) at androidx.compose.ui.test.junit4.AbstractMainTestClock.advanceTimeByFrame(AbstractMainTestClock.kt:38) at androidx.compose.ui.test.junit4.ComposeIdlingResource.isIdleNow(ComposeIdlingResource.android.kt:74) at androidx.compose.ui.test.junit4.RobolectricIdlingStrategy$runUntilIdle$1.invoke(RobolectricIdlingStrategy.android.kt:70) at androidx.compose.ui.test.junit4.RobolectricIdlingStrategy$runUntilIdle$1.invoke(RobolectricIdlingStrategy.android.kt:48) at androidx.compose.ui.test.junit4.AndroidSynchronization_androidKt.runOnUiThread(AndroidSynchronization.android.kt:33) at androidx.compose.ui.test.junit4.RobolectricIdlingStrategy.runUntilIdle(RobolectricIdlingStrategy.android.kt:48) at androidx.compose.ui.test.AndroidComposeUiTestEnvironment.waitForIdle(ComposeUiTest.android.kt:336) at androidx.compose.ui.test.AndroidComposeUiTestEnvironment.access$waitForIdle(ComposeUiTest.android.kt:228) at androidx.compose.ui.test.AndroidComposeUiTestEnvironment$AndroidComposeUiTestImpl.waitForIdle(ComposeUiTest.android.kt:406) at androidx.compose.ui.test.AndroidComposeUiTestEnvironment$AndroidComposeUiTestImpl.setContent(ComposeUiTest.android.kt:485) at androidx.compose.ui.test.junit4.AndroidComposeTestRule.setContent(AndroidComposeTestRule.android.kt:340) at com.x.y.BaseTest.withCompositionLocals(BaseTest.kt:109) at com.x.y.z.flightsinfosite.journeysummary.FlightsJourneySummaryLoadingTest$testJourneySummaryLoadingStateSuccess$1.invokeSuspend(FlightsJourneySummaryLoadingTest.kt:72) at com.x.y.z.flightsinfosite.journeysummary.FlightsJourneySummaryLoadingTest$testJourneySummaryLoadingStateSuccess$1.invoke(FlightsJourneySummaryLoadingTest.kt) at com.x.y.z.flightsinfosite.journeysummary.FlightsJourneySummaryLoadingTest$testJourneySummaryLoadingStateSuccess$1.invoke(FlightsJourneySummaryLoadingTest.kt) at kotlinx.coroutines.test.TestBuildersKt__TestBuildersKt$runTest$2$1$1.invokeSuspend(TestBuilders.kt:316) at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33) at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:104) at kotlinx.coroutines.test.TestDispatcher.processEvent$kotlinx_coroutines_test(TestDispatcher.kt:24) at kotlinx.coroutines.test.TestCoroutineScheduler.tryRunNextTaskUnless$kotlinx_coroutines_test(TestCoroutineScheduler.kt:99) at kotlinx.coroutines.test.TestBuildersKt__TestBuildersKt$runTest$2$1$workRunner$1.invokeSuspend(TestBuilders.kt:322) at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33) at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:104) at kotlinx.coroutines.EventLoopImplBase.processNextEvent(EventLoop.common.kt:277) at kotlinx.coroutines.BlockingCoroutine.joinBlocking(Builders.kt:95) at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking(Builders.kt:69) at kotlinx.coroutines.BuildersKt.runBlocking(Unknown Source) at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking$default(Builders.kt:48) at kotlinx.coroutines.BuildersKt.runBlocking$default(Unknown Source) at kotlinx.coroutines.test.TestBuildersJvmKt.createTestResult(TestBuildersJvm.kt:10) at kotlinx.coroutines.test.TestBuildersKt__TestBuildersKt.runTest-8Mi8wO0(TestBuilders.kt:310) at kotlinx.coroutines.test.TestBuildersKt.runTest-8Mi8wO0(Unknown Source) at kotlinx.coroutines.test.TestBuildersKt__TestBuildersKt.runTest-8Mi8wO0(TestBuilders.kt:168) at kotlinx.coroutines.test.TestBuildersKt.runTest-8Mi8wO0(Unknown Source) at kotlinx.coroutines.test.TestBuildersKt__TestBuildersKt.runTest-8Mi8wO0$default(TestBuilders.kt:160) at kotlinx.coroutines.test.TestBuildersKt.runTest-8Mi8wO0$default(Unknown Source) at com.x.y.z.flightsinfosite.journeysummary.FlightsJourneySummaryLoadingTest.testJourneySummaryLoadingStateSuccess(FlightsJourneySummaryLoadingTest.kt:57) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:568) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26) at org.junit.rules.TestWatcher$1.evaluate(TestWatcher.java:61) at org.junit.rules.ExternalResource$1.evaluate(ExternalResource.java:54) at androidx.compose.ui.test.junit4.AndroidComposeTestRule$apply$1$evaluate$1.invoke(AndroidComposeTestRule.android.kt:272) at androidx.compose.ui.test.junit4.AndroidComposeTestRule$apply$1$evaluate$1.invoke(AndroidComposeTestRule.android.kt:271) at androidx.compose.ui.test.AndroidComposeUiTestEnvironment$AndroidComposeUiTestImpl.withDisposableContent(ComposeUiTest.android.kt:491) at androidx.compose.ui.test.AndroidComposeUiTestEnvironment$runTest$1$1$1$1$1$1.invoke(ComposeUiTest.android.kt:323) at androidx.compose.ui.test.AndroidComposeUiTestEnvironment.withComposeIdlingResource(ComposeUiTest.android.kt:375) at androidx.compose.ui.test.AndroidComposeUiTestEnvironment.access$withComposeIdlingResource(ComposeUiTest.android.kt:228) at androidx.compose.ui.test.AndroidComposeUiTestEnvironment$runTest$1$1$1$1$1.invoke(ComposeUiTest.android.kt:322) at androidx.compose.ui.test.AndroidComposeUiTestEnvironment.withWindowRecomposer(ComposeUiTest.android.kt:349) at androidx.compose.ui.test.AndroidComposeUiTestEnvironment.access$withWindowRecomposer(ComposeUiTest.android.kt:228) at androidx.compose.ui.test.AndroidComposeUiTestEnvironment$runTest$1$1$1$1.invoke(ComposeUiTest.android.kt:321) at androidx.compose.ui.test.AndroidComposeUiTestEnvironment.withTestCoroutines(ComposeUiTest.android.kt:362) at androidx.compose.ui.test.AndroidComposeUiTestEnvironment.access$withTestCoroutines(ComposeUiTest.android.kt:228) at androidx.compose.ui.test.AndroidComposeUiTestEnvironment$runTest$1$1$1.invoke(ComposeUiTest.android.kt:320) at androidx.compose.ui.test.junit4.IdlingStrategy.withStrategy(IdlingStrategy.android.kt:52) at androidx.compose.ui.test.AndroidComposeUiTestEnvironment$runTest$1$1.invoke(ComposeUiTest.android.kt:319) at androidx.compose.ui.test.junit4.IdlingResourceRegistry.withRegistry(IdlingResourceRegistry.jvm.kt:157) at androidx.compose.ui.test.AndroidComposeUiTestEnvironment$runTest$1.invoke(ComposeUiTest.android.kt:318) at androidx.compose.ui.test.junit4.ComposeRootRegistry.withRegistry(ComposeRootRegistry.android.kt:146) at androidx.compose.ui.test.AndroidComposeUiTestEnvironment.runTest(ComposeUiTest.android.kt:317) at androidx.compose.ui.test.junit4.AndroidComposeTestRule$apply$1.evaluate(AndroidComposeTestRule.android.kt:271) at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306) at org.robolectric.RobolectricTestRunner$HelperTestRunner$1.evaluate(RobolectricTestRunner.java:580) at org.robolectric.internal.SandboxTestRunner$2.lambda$evaluate$2(SandboxTestRunner.java:287) at org.robolectric.internal.bytecode.Sandbox.lambda$runOnMainThread$0(Sandbox.java:99) at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) at java.base/java.lang.Thread.run(Thread.java:840)

[dkhalanskyjb]

Without a reproducer, it's completely unclear what happened in your project that could cause this. In any case, the most direct interpretation of your stacktrace is that the Flow you're trying to call collect on is null.