ConcurrentModificationException when resolving output classes

Version:
* KSP 2.2.20-2.0.4 (.3 was working fine)

Repro:
* Clone https://github.com/TWiStErRob/repros/tree/main/ksp/classesDirs-ConcurrentModificationException
* `gradlew koverXmlReport`

Could not determine the dependencies of task ':koverGenerateArtifactDebug'. ConcurrentModificationException (no error message)

```
% gradlew koverXmlReport -S

FAILURE: Build failed with an exception.

* What went wrong:
Could not determine the dependencies of task ':koverGenerateArtifactDebug'.
> java.util.ConcurrentModificationException (no error message)

* Try:
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.
> Get more help at https://help.gradle.org.

* Exception is:
org.gradle.api.internal.tasks.TaskDependencyResolveException: Could not determine the dependencies of task ':koverGenerateArtifactDebug'.
at org.gradle.api.internal.tasks.CachingTaskDependencyResolveContext.getDependencies(CachingTaskDependencyResolveContext.java:70)
at org.gradle.execution.plan.TaskDependencyResolver.resolveDependenciesFor(TaskDependencyResolver.java:49)
at org.gradle.execution.plan.LocalTaskNode.getDependencies(LocalTaskNode.java:151)
at org.gradle.execution.plan.LocalTaskNode.resolveDependencies(LocalTaskNode.java:125)
at org.gradle.execution.plan.DefaultExecutionPlan.discoverNodeRelationships(DefaultExecutionPlan.java:182)
at org.gradle.execution.plan.DefaultExecutionPlan.doAddEntryNodes(DefaultExecutionPlan.java:154)
at org.gradle.execution.plan.DefaultExecutionPlan.addEntryTasks(DefaultExecutionPlan.java:129)
at org.gradle.execution.plan.DefaultExecutionPlan.addEntryTasks(DefaultExecutionPlan.java:121)
at org.gradle.execution.TaskNameResolvingBuildTaskScheduler.scheduleRequestedTasks(TaskNameResolvingBuildTaskScheduler.java:61)
at org.gradle.execution.DefaultTasksBuildTaskScheduler.scheduleRequestedTasks(DefaultTasksBuildTaskScheduler.java:72)
at org.gradle.initialization.DefaultTaskExecutionPreparer.lambda$scheduleRequestedTasks$0(DefaultTaskExecutionPreparer.java:48)
at org.gradle.internal.Factories$1.create(Factories.java:31)
at org.gradle.internal.work.DefaultWorkerLeaseService.withReplacedLocks(DefaultWorkerLeaseService.java:359)
at org.gradle.api.internal.project.DefaultProjectStateRegistry$DefaultBuildProjectRegistry.withMutableStateOfAllProjects(DefaultProjectStateRegistry.java:239)
at org.gradle.api.internal.project.DefaultProjectStateRegistry$DefaultBuildProjectRegistry.withMutableStateOfAllProjects(DefaultProjectStateRegistry.java:232)
at org.gradle.initialization.DefaultTaskExecutionPreparer.scheduleRequestedTasks(DefaultTaskExecutionPreparer.java:47)
at org.gradle.initialization.VintageBuildModelController.lambda$scheduleRequestedTasks$0(VintageBuildModelController.java:76)
at org.gradle.internal.model.StateTransitionController.lambda$inState$1(StateTransitionController.java:99)
at org.gradle.internal.model.StateTransitionController.lambda$inState$2(StateTransitionController.java:114)
at org.gradle.internal.work.DefaultSynchronizer.withLock(DefaultSynchronizer.java:46)
at org.gradle.internal.model.StateTransitionController.inState(StateTransitionController.java:110)
at org.gradle.internal.model.StateTransitionController.inState(StateTransitionController.java:98)
at org.gradle.initialization.VintageBuildModelController.scheduleRequestedTasks(VintageBuildModelController.java:76)
at org.gradle.internal.build.DefaultBuildLifecycleController$DefaultWorkGraphBuilder.addRequestedTasks(DefaultBuildLifecycleController.java:404)
at org.gradle.internal.buildtree.DefaultBuildTreeWorkPreparer.lambda$scheduleRequestedTasks$0(DefaultBuildTreeWorkPreparer.java:41)
at org.gradle.internal.build.DefaultBuildLifecycleController.lambda$populateWorkGraph$7(DefaultBuildLifecycleController.java:189)
at org.gradle.internal.build.DefaultBuildWorkPreparer.populateWorkGraph(DefaultBuildWorkPreparer.java:42)
at org.gradle.internal.build.BuildOperationFiringBuildWorkPreparer$PopulateWorkGraph.populateTaskGraph(BuildOperationFiringBuildWorkPreparer.java:106)
at org.gradle.internal.build.BuildOperationFiringBuildWorkPreparer$PopulateWorkGraph.run(BuildOperationFiringBuildWorkPreparer.java:92)
at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:30)
at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:27)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:67)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:60)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:167)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:60)
at org.gradle.internal.operations.DefaultBuildOperationRunner.run(DefaultBuildOperationRunner.java:48)
at org.gradle.internal.build.BuildOperationFiringBuildWorkPreparer.populateWorkGraph(BuildOperationFiringBuildWorkPreparer.java:67)
at org.gradle.internal.build.DefaultBuildLifecycleController.lambda$populateWorkGraph$8(DefaultBuildLifecycleController.java:189)
at org.gradle.internal.model.StateTransitionController.lambda$inState$1(StateTransitionController.java:99)
at org.gradle.internal.model.StateTransitionController.lambda$inState$2(StateTransitionController.java:114)
at org.gradle.internal.work.DefaultSynchronizer.withLock(DefaultSynchronizer.java:46)
at org.gradle.internal.model.StateTransitionController.inState(StateTransitionController.java:110)
at org.gradle.internal.model.StateTransitionController.inState(StateTransitionController.java:98)
at org.gradle.internal.build.DefaultBuildLifecycleController.populateWorkGraph(DefaultBuildLifecycleController.java:189)
at org.gradle.internal.build.DefaultBuildWorkGraphController$DefaultBuildWorkGraph.populateWorkGraph(DefaultBuildWorkGraphController.java:169)
at org.gradle.composite.internal.DefaultBuildController.populateWorkGraph(DefaultBuildController.java:76)
at org.gradle.composite.internal.DefaultIncludedBuildTaskGraph$DefaultBuildTreeWorkGraphBuilder.withWorkGraph(DefaultIncludedBuildTaskGraph.java:153)
at org.gradle.internal.buildtree.DefaultBuildTreeWorkPreparer.lambda$scheduleRequestedTasks$1(DefaultBuildTreeWorkPreparer.java:41)
at org.gradle.composite.internal.DefaultIncludedBuildTaskGraph$DefaultBuildTreeWorkGraph$1.run(DefaultIncludedBuildTaskGraph.java:209)
at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:30)
at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:27)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:67)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:60)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:167)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:60)
at org.gradle.internal.operations.DefaultBuildOperationRunner.run(DefaultBuildOperationRunner.java:48)
at org.gradle.composite.internal.DefaultIncludedBuildTaskGraph$DefaultBuildTreeWorkGraph.scheduleWork(DefaultIncludedBuildTaskGraph.java:204)
at org.gradle.internal.buildtree.DefaultBuildTreeWorkPreparer.scheduleRequestedTasks(DefaultBuildTreeWorkPreparer.java:37)
at org.gradle.internal.cc.impl.VintageBuildTreeWorkController$scheduleAndRunRequestedTasks$1.apply(VintageBuildTreeWorkController.kt:36)
at org.gradle.internal.cc.impl.VintageBuildTreeWorkController$scheduleAndRunRequestedTasks$1.apply(VintageBuildTreeWorkController.kt:35)
at org.gradle.composite.internal.DefaultIncludedBuildTaskGraph.withNewWorkGraph(DefaultIncludedBuildTaskGraph.java:112)
at org.gradle.internal.cc.impl.VintageBuildTreeWorkController.scheduleAndRunRequestedTasks(VintageBuildTreeWorkController.kt:35)
at org.gradle.internal.buildtree.DefaultBuildTreeLifecycleController.lambda$scheduleAndRunTasks$1(DefaultBuildTreeLifecycleController.java:77)
at org.gradle.internal.buildtree.DefaultBuildTreeLifecycleController.lambda$runBuild$4(DefaultBuildTreeLifecycleController.java:120)
at org.gradle.internal.model.StateTransitionController.lambda$transition$6(StateTransitionController.java:169)
at org.gradle.internal.model.StateTransitionController.doTransition(StateTransitionController.java:266)
at org.gradle.internal.model.StateTransitionController.lambda$transition$7(StateTransitionController.java:169)
at org.gradle.internal.work.DefaultSynchronizer.withLock(DefaultSynchronizer.java:46)
at org.gradle.internal.model.StateTransitionController.transition(StateTransitionController.java:169)
at org.gradle.internal.buildtree.DefaultBuildTreeLifecycleController.runBuild(DefaultBuildTreeLifecycleController.java:117)
at org.gradle.internal.buildtree.DefaultBuildTreeLifecycleController.scheduleAndRunTasks(DefaultBuildTreeLifecycleController.java:77)
at org.gradle.internal.buildtree.DefaultBuildTreeLifecycleController.scheduleAndRunTasks(DefaultBuildTreeLifecycleController.java:72)
at org.gradle.tooling.internal.provider.ExecuteBuildActionRunner.run(ExecuteBuildActionRunner.java:31)
at org.gradle.launcher.exec.ChainingBuildActionRunner.run(ChainingBuildActionRunner.java:35)
at org.gradle.internal.buildtree.ProblemReportingBuildActionRunner.run(ProblemReportingBuildActionRunner.java:49)
at org.gradle.launcher.exec.BuildOutcomeReportingBuildActionRunner.run(BuildOutcomeReportingBuildActionRunner.java:71)
at org.gradle.tooling.internal.provider.FileSystemWatchingBuildActionRunner.run(FileSystemWatchingBuildActionRunner.java:135)
at org.gradle.launcher.exec.BuildCompletionNotifyingBuildActionRunner.run(BuildCompletionNotifyingBuildActionRunner.java:41)
at org.gradle.launcher.exec.RootBuildLifecycleBuildActionExecutor.lambda$execute$0(RootBuildLifecycleBuildActionExecutor.java:54)
at org.gradle.composite.internal.DefaultRootBuildState.run(DefaultRootBuildState.java:130)
at org.gradle.launcher.exec.RootBuildLifecycleBuildActionExecutor.execute(RootBuildLifecycleBuildActionExecutor.java:54)
at org.gradle.internal.buildtree.InitDeprecationLoggingActionExecutor.execute(InitDeprecationLoggingActionExecutor.java:62)
at org.gradle.internal.buildtree.InitProblems.execute(InitProblems.java:36)
at org.gradle.internal.buildtree.DefaultBuildTreeContext.execute(DefaultBuildTreeContext.java:40)
at org.gradle.launcher.exec.BuildTreeLifecycleBuildActionExecutor.lambda$execute$0(BuildTreeLifecycleBuildActionExecutor.java:71)
at org.gradle.internal.buildtree.BuildTreeState.run(BuildTreeState.java:60)
at org.gradle.launcher.exec.BuildTreeLifecycleBuildActionExecutor.execute(BuildTreeLifecycleBuildActionExecutor.java:71)
at org.gradle.launcher.exec.RunAsBuildOperationBuildActionExecutor$2.call(RunAsBuildOperationBuildActionExecutor.java:67)
at org.gradle.launcher.exec.RunAsBuildOperationBuildActionExecutor$2.call(RunAsBuildOperationBuildActionExecutor.java:63)
at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:210)
at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:205)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:67)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:60)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:167)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:60)
at org.gradle.internal.operations.DefaultBuildOperationRunner.call(DefaultBuildOperationRunner.java:54)
at org.gradle.launcher.exec.RunAsBuildOperationBuildActionExecutor.execute(RunAsBuildOperationBuildActionExecutor.java:63)
at org.gradle.launcher.exec.RunAsWorkerThreadBuildActionExecutor.lambda$execute$0(RunAsWorkerThreadBuildActionExecutor.java:36)
at org.gradle.internal.work.DefaultWorkerLeaseService.withLocks(DefaultWorkerLeaseService.java:263)
at org.gradle.internal.work.DefaultWorkerLeaseService.runAsWorkerThread(DefaultWorkerLeaseService.java:127)
at org.gradle.launcher.exec.RunAsWorkerThreadBuildActionExecutor.execute(RunAsWorkerThreadBuildActionExecutor.java:36)
at org.gradle.tooling.internal.provider.continuous.ContinuousBuildActionExecutor.execute(ContinuousBuildActionExecutor.java:110)
at org.gradle.tooling.internal.provider.SubscribableBuildActionExecutor.execute(SubscribableBuildActionExecutor.java:64)
at org.gradle.internal.session.DefaultBuildSessionContext.execute(DefaultBuildSessionContext.java:46)
at org.gradle.internal.buildprocess.execution.BuildSessionLifecycleBuildActionExecutor$ActionImpl.apply(BuildSessionLifecycleBuildActionExecutor.java:92)
at org.gradle.internal.buildprocess.execution.BuildSessionLifecycleBuildActionExecutor$ActionImpl.apply(BuildSessionLifecycleBuildActionExecutor.java:80)
at org.gradle.internal.session.BuildSessionState.run(BuildSessionState.java:73)
at org.gradle.internal.buildprocess.execution.BuildSessionLifecycleBuildActionExecutor.execute(BuildSessionLifecycleBuildActionExecutor.java:62)
at org.gradle.internal.buildprocess.execution.BuildSessionLifecycleBuildActionExecutor.execute(BuildSessionLifecycleBuildActionExecutor.java:41)
at org.gradle.internal.buildprocess.execution.StartParamsValidatingActionExecutor.execute(StartParamsValidatingActionExecutor.java:64)
at org.gradle.internal.buildprocess.execution.StartParamsValidatingActionExecutor.execute(StartParamsValidatingActionExecutor.java:32)
at org.gradle.internal.buildprocess.execution.SessionFailureReportingActionExecutor.execute(SessionFailureReportingActionExecutor.java:51)
at org.gradle.internal.buildprocess.execution.SessionFailureReportingActionExecutor.execute(SessionFailureReportingActionExecutor.java:39)
at org.gradle.internal.buildprocess.execution.SetupLoggingActionExecutor.execute(SetupLoggingActionExecutor.java:47)
at org.gradle.internal.buildprocess.execution.SetupLoggingActionExecutor.execute(SetupLoggingActionExecutor.java:31)
at org.gradle.launcher.daemon.server.exec.ExecuteBuild.doBuild(ExecuteBuild.java:70)
at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:37)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
at org.gradle.launcher.daemon.server.exec.WatchForDisconnection.execute(WatchForDisconnection.java:39)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
at org.gradle.launcher.daemon.server.exec.ResetDeprecationLogger.execute(ResetDeprecationLogger.java:29)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
at org.gradle.launcher.daemon.server.exec.RequestStopIfSingleUsedDaemon.execute(RequestStopIfSingleUsedDaemon.java:35)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
at org.gradle.launcher.daemon.server.exec.ForwardClientInput.lambda$execute$0(ForwardClientInput.java:40)
at org.gradle.internal.daemon.clientinput.ClientInputForwarder.forwardInput(ClientInputForwarder.java:80)
at org.gradle.launcher.daemon.server.exec.ForwardClientInput.execute(ForwardClientInput.java:37)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
at org.gradle.launcher.daemon.server.exec.LogAndCheckHealth.execute(LogAndCheckHealth.java:64)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
at org.gradle.launcher.daemon.server.exec.LogToClient.doBuild(LogToClient.java:63)
at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:37)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
at org.gradle.launcher.daemon.server.exec.EstablishBuildEnvironment.doBuild(EstablishBuildEnvironment.java:84)
at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:37)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
at org.gradle.launcher.daemon.server.exec.StartBuildOrRespondWithBusy$1.run(StartBuildOrRespondWithBusy.java:52)
at org.gradle.launcher.daemon.server.DaemonStateCoordinator.lambda$runCommand$0(DaemonStateCoordinator.java:321)
at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64)
at org.gradle.internal.concurrent.AbstractManagedExecutor$1.run(AbstractManagedExecutor.java:48)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
at java.base/java.lang.Thread.run(Thread.java:1583)
Caused by: java.util.ConcurrentModificationException
at java.base/java.util.LinkedHashMap$LinkedHashIterator.nextNode(LinkedHashMap.java:1023)
at java.base/java.util.LinkedHashMap$LinkedKeyIterator.next(LinkedHashMap.java:1046)
at org.gradle.api.internal.file.collections.DefaultConfigurableFileCollection$UnresolvedItemsCollector.visitContents(DefaultConfigurableFileCollection.java:634)
at org.gradle.api.internal.file.collections.DefaultConfigurableFileCollection.visitChildren(DefaultConfigurableFileCollection.java:448)
at org.gradle.api.internal.file.CompositeFileCollection.visitContents(CompositeFileCollection.java:112)
at org.gradle.api.internal.file.AbstractFileCollection.getFiles(AbstractFileCollection.java:124)
at kotlinx.kover.gradle.plugin.locators.JvmKt.extractJvmCompilation(Jvm.kt:32)
at kotlinx.kover.gradle.plugin.locators.JvmKt.jvmCompilations(Jvm.kt:20)
at kotlinx.kover.gradle.plugin.locators.AndroidKt.extractCompilation(Android.kt:100)
at kotlinx.kover.gradle.plugin.locators.AndroidKt.access$extractCompilation(Android.kt:1)
at kotlinx.kover.gradle.plugin.locators.AndroidKt$extractAndroidKit$compilations$1.call(Android.kt:49)
at kotlinx.kover.gradle.plugin.locators.AndroidKt$extractAndroidKit$compilations$1.call(Android.kt:48)
at org.gradle.api.internal.provider.DefaultProvider.calculateOwnValue(DefaultProvider.java:73)
at org.gradle.api.internal.provider.AbstractMinimalProvider.calculateValue(AbstractMinimalProvider.java:117)
at org.gradle.api.internal.provider.TransformBackedProvider.calculateOwnValue(TransformBackedProvider.java:82)
at org.gradle.api.internal.provider.AbstractMinimalProvider.calculateValue(AbstractMinimalProvider.java:117)
at org.gradle.api.internal.provider.TransformBackedProvider.calculateOwnValue(TransformBackedProvider.java:82)
at org.gradle.api.internal.provider.AbstractMinimalProvider.calculateOwnPresentValue(AbstractMinimalProvider.java:82)
at org.gradle.api.internal.provider.AbstractMinimalProvider.get(AbstractMinimalProvider.java:102)
at org.gradle.api.internal.tasks.DefaultTaskDependency.visitDependencies(DefaultTaskDependency.java:109)
at org.gradle.api.internal.tasks.CachingTaskDependencyResolveContext$TaskGraphImpl.getNodeValues(CachingTaskDependencyResolveContext.java:108)
at org.gradle.internal.graph.CachingDirectedGraphWalker$GraphWithEmptyEdges.getNodeValues(CachingDirectedGraphWalker.java:219)
at org.gradle.internal.graph.CachingDirectedGraphWalker.doSearch(CachingDirectedGraphWalker.java:127)
at org.gradle.internal.graph.CachingDirectedGraphWalker.findValues(CachingDirectedGraphWalker.java:79)
at org.gradle.api.internal.tasks.CachingTaskDependencyResolveContext.getDependencies(CachingTaskDependencyResolveContext.java:67)
... 142 more

BUILD FAILED in 574ms
```

The essence of what Kover is doing (also reproduces the issue):

```gradle.kts
afterEvaluate {
val variantName = android.libraryVariants.first().name
val compilation = kotlin.target.compilations.get(variantName)
println(compilation.output.classesDirs.files)
}
```

After a few hours of trying to debug Gradle/JVM internals I managed to find an easy-ish way to investigate:
1. Breakpoint at `kover-gradle-plugin-0.9.2-sources.jar!/kotlinx/kover/gradle/plugin/locators/Jvm.kt:24`, with suspend: none.

2. Breakpoint at `org.gradle.api.internal.file.collections.DefaultConfigurableFileCollection.UnresolvedItemsCollector.visitContents` with "Disable until hitting: Jvm.kt:32".

3. `gradlew --no-daemon koverXmlReport -Dorg.gradle.debug=true`

Then I figured out a way to show what is actually happening.

We can see that at the 2nd breakpoint we have:
```
0 = {FlatMapProvider@37119} "flatmap(provider(task 'compileDebugKotlin', class org.jetbrains.kotlin.gradle.tasks.KotlinCompile))"
1 = {FlatMapProvider@37120} "flatmap(provider(task 'compileDebugJavaWithJavac', class org.gradle.api.tasks.compile.JavaCompile))"
```
when the first `item` is iterated it gets resolved, and that adds a 3rd item to `items`:
```
2 = {TransformBackedProvider@39242} "map(map(org.gradle.api.file.Directory property 'buildDir' org.gradle.api.internal.file.DefaultFilePropertyFactory$PathToDirectoryTransformer@584417e3))"
```
and bang `ConcurrentModificationException`. But what is that mysterious 3rd item? Expanding the transformer we can see:
```
2 = {TransformBackedProvider@39242} "map(map(org.gradle.api.file.Directory property 'buildDir' org.gradle.api.internal.file.DefaultFilePropertyFactory$PathToDirectoryTransformer@584417e3))"
provider = {MappingProvider@39245} "map(org.gradle.api.file.Directory property 'buildDir' org.gradle.api.internal.file.DefaultFilePropertyFactory$PathToDirectoryTransformer@584417e3)"
type = {Class@32225} "interface org.gradle.api.file.Directory"
provider = {DefaultFilePropertyFactory$DefaultDirectoryVar@39248} "property 'buildDir'"
transformer = {DefaultFilePropertyFactory$PathToDirectoryTransformer@39249}
path = "generated/ksp//debug"
transformer = {KspGradleSubplugin$Companion$lambda@39246}
arg$1 = {KspGradleSubplugin$Companion$getKspClassOutputDir$1@39271} (org.gradle.api.file.Directory!) -> org.gradle.api.file.Directory
```
the lambda inner classes are helpful, but still doesn't explain what is actually configuring those.
When the `for` loop is hit in the debugger I replaced `this.items = Collections.unmodifiableSet(this.items)`:
```java
Field f = this.getClass().getDeclaredField("items");
f.setAccessible(true);
f.set(this, Collections.unmodifiableSet(items));
```
so that whoever is adding it will crash immediately. And sure enough, the stack trace points to:

com.google.devtools.ksp.gradle.KspAATask$Companion$registerKspAATask$kspTaskProvider$1.invoke(KspAATask.kt:336)

```
* What went wrong:
Could not determine the dependencies of task ':app:koverGenerateArtifactDebug'.
> Could not create task ':app:compileDebugKotlin'.
> Could not create task ':app:kspDebugKotlin'.
> java.lang.UnsupportedOperationException (no error message)

* Try:
> Run with --info or --debug option to get more log output.
> Run with --scan to generate a Build Scan (Powered by Develocity).
> Get more help at https://help.gradle.org.

* Exception is:
org.gradle.api.internal.tasks.TaskDependencyResolveException: Could not determine the dependencies of task ':app:koverGenerateArtifactDebug'.
at org.gradle.api.internal.tasks.CachingTaskDependencyResolveContext.getDependencies(CachingTaskDependencyResolveContext.java:70)
at org.gradle.execution.plan.TaskDependencyResolver.resolveDependenciesFor(TaskDependencyResolver.java:49)
at org.gradle.execution.plan.LocalTaskNode.getDependencies(LocalTaskNode.java:151)
at org.gradle.execution.plan.LocalTaskNode.resolveDependencies(LocalTaskNode.java:125)
at org.gradle.execution.plan.DefaultExecutionPlan.discoverNodeRelationships(DefaultExecutionPlan.java:182)
at org.gradle.execution.plan.DefaultExecutionPlan.doAddEntryNodes(DefaultExecutionPlan.java:154)
at org.gradle.execution.plan.DefaultExecutionPlan.addEntryTasks(DefaultExecutionPlan.java:129)
at org.gradle.execution.plan.DefaultExecutionPlan.addEntryTasks(DefaultExecutionPlan.java:121)
at org.gradle.execution.TaskNameResolvingBuildTaskScheduler.scheduleRequestedTasks(TaskNameResolvingBuildTaskScheduler.java:69)
at org.gradle.execution.DefaultTasksBuildTaskScheduler.scheduleRequestedTasks(DefaultTasksBuildTaskScheduler.java:72)
at org.gradle.initialization.DefaultTaskExecutionPreparer.lambda$scheduleRequestedTasks$0(DefaultTaskExecutionPreparer.java:47)
at org.gradle.internal.Factories$1.create(Factories.java:31)
at org.gradle.internal.work.DefaultWorkerLeaseService.withReplacedLocks(DefaultWorkerLeaseService.java:359)
at org.gradle.api.internal.project.DefaultProjectStateRegistry$DefaultBuildProjectRegistry.withMutableStateOfAllProjects(DefaultProjectStateRegistry.java:246)
at org.gradle.api.internal.project.DefaultProjectStateRegistry$DefaultBuildProjectRegistry.withMutableStateOfAllProjects(DefaultProjectStateRegistry.java:239)
at org.gradle.initialization.DefaultTaskExecutionPreparer.scheduleRequestedTasks(DefaultTaskExecutionPreparer.java:46)
at org.gradle.initialization.VintageBuildModelController.lambda$scheduleRequestedTasks$0(VintageBuildModelController.java:75)
at org.gradle.internal.model.StateTransitionController.lambda$inState$1(StateTransitionController.java:99)
at org.gradle.internal.model.StateTransitionController.lambda$inState$2(StateTransitionController.java:114)
at org.gradle.internal.work.DefaultSynchronizer.withLock(DefaultSynchronizer.java:45)
at org.gradle.internal.model.StateTransitionController.inState(StateTransitionController.java:110)
at org.gradle.internal.model.StateTransitionController.inState(StateTransitionController.java:98)
at org.gradle.initialization.VintageBuildModelController.scheduleRequestedTasks(VintageBuildModelController.java:75)
at org.gradle.internal.cc.impl.ConfigurationCacheAwareBuildModelController.scheduleRequestedTasks(ConfigurationCacheAwareBuildModelController.kt:55)
at org.gradle.internal.build.DefaultBuildLifecycleController$DefaultWorkGraphBuilder.addRequestedTasks(DefaultBuildLifecycleController.java:404)
at org.gradle.internal.buildtree.DefaultBuildTreeWorkPreparer.lambda$scheduleRequestedTasks$0(DefaultBuildTreeWorkPreparer.java:40)
at org.gradle.internal.build.DefaultBuildLifecycleController.lambda$populateWorkGraph$7(DefaultBuildLifecycleController.java:189)
at org.gradle.internal.build.DefaultBuildWorkPreparer.populateWorkGraph(DefaultBuildWorkPreparer.java:42)
at org.gradle.internal.build.BuildOperationFiringBuildWorkPreparer$PopulateWorkGraph.populateTaskGraph(BuildOperationFiringBuildWorkPreparer.java:106)
at org.gradle.internal.build.BuildOperationFiringBuildWorkPreparer$PopulateWorkGraph.run(BuildOperationFiringBuildWorkPreparer.java:92)
at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:29)
at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:26)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:66)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:59)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:166)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:59)
at org.gradle.internal.operations.DefaultBuildOperationRunner.run(DefaultBuildOperationRunner.java:47)
at org.gradle.internal.build.BuildOperationFiringBuildWorkPreparer.populateWorkGraph(BuildOperationFiringBuildWorkPreparer.java:67)
at org.gradle.internal.build.DefaultBuildLifecycleController.lambda$populateWorkGraph$8(DefaultBuildLifecycleController.java:189)
at org.gradle.internal.model.StateTransitionController.lambda$inState$1(StateTransitionController.java:99)
at org.gradle.internal.model.StateTransitionController.lambda$inState$2(StateTransitionController.java:114)
at org.gradle.internal.work.DefaultSynchronizer.withLock(DefaultSynchronizer.java:45)
at org.gradle.internal.model.StateTransitionController.inState(StateTransitionController.java:110)
at org.gradle.internal.model.StateTransitionController.inState(StateTransitionController.java:98)
at org.gradle.internal.build.DefaultBuildLifecycleController.populateWorkGraph(DefaultBuildLifecycleController.java:189)
at org.gradle.internal.build.DefaultBuildWorkGraphController$DefaultBuildWorkGraph.populateWorkGraph(DefaultBuildWorkGraphController.java:169)
at org.gradle.composite.internal.DefaultBuildController.populateWorkGraph(DefaultBuildController.java:76)
at org.gradle.composite.internal.DefaultIncludedBuildTaskGraph$DefaultBuildTreeWorkGraphBuilder.withWorkGraph(DefaultIncludedBuildTaskGraph.java:155)
at org.gradle.internal.buildtree.DefaultBuildTreeWorkPreparer.lambda$scheduleRequestedTasks$1(DefaultBuildTreeWorkPreparer.java:40)
at org.gradle.composite.internal.DefaultIncludedBuildTaskGraph$DefaultBuildTreeWorkGraph$1.run(DefaultIncludedBuildTaskGraph.java:211)
at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:29)
at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:26)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:66)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:59)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:166)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:59)
at org.gradle.internal.operations.DefaultBuildOperationRunner.run(DefaultBuildOperationRunner.java:47)
at org.gradle.composite.internal.DefaultIncludedBuildTaskGraph$DefaultBuildTreeWorkGraph.scheduleWork(DefaultIncludedBuildTaskGraph.java:206)
at org.gradle.internal.buildtree.DefaultBuildTreeWorkPreparer.scheduleRequestedTasks(DefaultBuildTreeWorkPreparer.java:36)
at org.gradle.internal.cc.impl.ConfigurationCacheAwareBuildTreeWorkController$scheduleAndRunRequestedTasks$executionResult$1.apply$lambda$0(ConfigurationCacheAwareBuildTreeWorkController.kt:58)
at org.gradle.internal.cc.impl.DefaultConfigurationCache.loadOrScheduleRequestedTasks$lambda$11(DefaultConfigurationCache.kt:270)
at org.gradle.internal.cc.impl.DefaultConfigurationCache.runWorkThatContributesToCacheEntry(DefaultConfigurationCache.kt:620)
at org.gradle.internal.cc.impl.DefaultConfigurationCache.loadOrScheduleRequestedTasks(DefaultConfigurationCache.kt:269)
at org.gradle.internal.cc.impl.ConfigurationCacheAwareBuildTreeWorkController$scheduleAndRunRequestedTasks$executionResult$1.apply(ConfigurationCacheAwareBuildTreeWorkController.kt:55)
at org.gradle.internal.cc.impl.ConfigurationCacheAwareBuildTreeWorkController$scheduleAndRunRequestedTasks$executionResult$1.apply(ConfigurationCacheAwareBuildTreeWorkController.kt:54)
at org.gradle.composite.internal.DefaultIncludedBuildTaskGraph.withNewWorkGraph(DefaultIncludedBuildTaskGraph.java:114)
at org.gradle.internal.cc.impl.ConfigurationCacheAwareBuildTreeWorkController.scheduleAndRunRequestedTasks(ConfigurationCacheAwareBuildTreeWorkController.kt:54)
at org.gradle.internal.buildtree.DefaultBuildTreeLifecycleController.lambda$scheduleAndRunTasks$1(DefaultBuildTreeLifecycleController.java:77)
at org.gradle.internal.buildtree.DefaultBuildTreeLifecycleController.lambda$runBuild$4(DefaultBuildTreeLifecycleController.java:120)
at org.gradle.internal.model.StateTransitionController.lambda$transition$6(StateTransitionController.java:169)
at org.gradle.internal.model.StateTransitionController.doTransition(StateTransitionController.java:266)
at org.gradle.internal.model.StateTransitionController.lambda$transition$7(StateTransitionController.java:169)
at org.gradle.internal.work.DefaultSynchronizer.withLock(DefaultSynchronizer.java:45)
at org.gradle.internal.model.StateTransitionController.transition(StateTransitionController.java:169)
at org.gradle.internal.buildtree.DefaultBuildTreeLifecycleController.runBuild(DefaultBuildTreeLifecycleController.java:117)
at org.gradle.internal.buildtree.DefaultBuildTreeLifecycleController.scheduleAndRunTasks(DefaultBuildTreeLifecycleController.java:77)
at org.gradle.internal.buildtree.DefaultBuildTreeLifecycleController.scheduleAndRunTasks(DefaultBuildTreeLifecycleController.java:72)
at org.gradle.tooling.internal.provider.ExecuteBuildActionRunner.run(ExecuteBuildActionRunner.java:31)
at org.gradle.launcher.exec.ChainingBuildActionRunner.run(ChainingBuildActionRunner.java:35)
at org.gradle.internal.buildtree.ProblemReportingBuildActionRunner.run(ProblemReportingBuildActionRunner.java:54)
at org.gradle.launcher.exec.BuildOutcomeReportingBuildActionRunner.run(BuildOutcomeReportingBuildActionRunner.java:83)
at org.gradle.tooling.internal.provider.FileSystemWatchingBuildActionRunner.run(FileSystemWatchingBuildActionRunner.java:135)
at org.gradle.launcher.exec.BuildCompletionNotifyingBuildActionRunner.run(BuildCompletionNotifyingBuildActionRunner.java:54)
at org.gradle.launcher.exec.RootBuildLifecycleBuildActionExecutor.lambda$execute$0(RootBuildLifecycleBuildActionExecutor.java:56)
at org.gradle.composite.internal.DefaultRootBuildState.run(DefaultRootBuildState.java:131)
at org.gradle.launcher.exec.RootBuildLifecycleBuildActionExecutor.execute(RootBuildLifecycleBuildActionExecutor.java:56)
at org.gradle.internal.buildtree.InitDeprecationLoggingActionExecutor.execute(InitDeprecationLoggingActionExecutor.java:62)
at org.gradle.internal.buildtree.InitProblems.execute(InitProblems.java:36)
at org.gradle.internal.buildtree.DefaultBuildTreeContext.execute(DefaultBuildTreeContext.java:40)
at org.gradle.launcher.exec.BuildTreeLifecycleBuildActionExecutor.lambda$execute$0(BuildTreeLifecycleBuildActionExecutor.java:71)
at org.gradle.internal.buildtree.BuildTreeState.run(BuildTreeState.java:60)
at org.gradle.launcher.exec.BuildTreeLifecycleBuildActionExecutor.execute(BuildTreeLifecycleBuildActionExecutor.java:71)
at org.gradle.launcher.exec.RunAsBuildOperationBuildActionExecutor$2.call(RunAsBuildOperationBuildActionExecutor.java:65)
at org.gradle.launcher.exec.RunAsBuildOperationBuildActionExecutor$2.call(RunAsBuildOperationBuildActionExecutor.java:61)
at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:209)
at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:204)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:66)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:59)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:166)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:59)
at org.gradle.internal.operations.DefaultBuildOperationRunner.call(DefaultBuildOperationRunner.java:53)
at org.gradle.launcher.exec.RunAsBuildOperationBuildActionExecutor.execute(RunAsBuildOperationBuildActionExecutor.java:61)
at org.gradle.launcher.exec.RunAsWorkerThreadBuildActionExecutor.lambda$execute$0(RunAsWorkerThreadBuildActionExecutor.java:36)
at org.gradle.internal.work.DefaultWorkerLeaseService.withLocks(DefaultWorkerLeaseService.java:263)
at org.gradle.internal.work.DefaultWorkerLeaseService.runAsWorkerThread(DefaultWorkerLeaseService.java:127)
at org.gradle.launcher.exec.RunAsWorkerThreadBuildActionExecutor.execute(RunAsWorkerThreadBuildActionExecutor.java:36)
at org.gradle.tooling.internal.provider.continuous.ContinuousBuildActionExecutor.execute(ContinuousBuildActionExecutor.java:110)
at org.gradle.tooling.internal.provider.SubscribableBuildActionExecutor.execute(SubscribableBuildActionExecutor.java:64)
at org.gradle.internal.session.DefaultBuildSessionContext.execute(DefaultBuildSessionContext.java:46)
at org.gradle.internal.buildprocess.execution.BuildSessionLifecycleBuildActionExecutor$ActionImpl.apply(BuildSessionLifecycleBuildActionExecutor.java:92)
at org.gradle.internal.buildprocess.execution.BuildSessionLifecycleBuildActionExecutor$ActionImpl.apply(BuildSessionLifecycleBuildActionExecutor.java:80)
at org.gradle.internal.session.BuildSessionState.run(BuildSessionState.java:73)
at org.gradle.internal.buildprocess.execution.BuildSessionLifecycleBuildActionExecutor.execute(BuildSessionLifecycleBuildActionExecutor.java:62)
at org.gradle.internal.buildprocess.execution.BuildSessionLifecycleBuildActionExecutor.execute(BuildSessionLifecycleBuildActionExecutor.java:41)
at org.gradle.internal.buildprocess.execution.StartParamsValidatingActionExecutor.execute(StartParamsValidatingActionExecutor.java:57)
at org.gradle.internal.buildprocess.execution.StartParamsValidatingActionExecutor.execute(StartParamsValidatingActionExecutor.java:32)
at org.gradle.internal.buildprocess.execution.SessionFailureReportingActionExecutor.execute(SessionFailureReportingActionExecutor.java:51)
at org.gradle.internal.buildprocess.execution.SessionFailureReportingActionExecutor.execute(SessionFailureReportingActionExecutor.java:39)
at org.gradle.internal.buildprocess.execution.SetupLoggingActionExecutor.execute(SetupLoggingActionExecutor.java:47)
at org.gradle.internal.buildprocess.execution.SetupLoggingActionExecutor.execute(SetupLoggingActionExecutor.java:31)
at org.gradle.launcher.daemon.server.exec.ExecuteBuild.doBuild(ExecuteBuild.java:70)
at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:37)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
at org.gradle.launcher.daemon.server.exec.WatchForDisconnection.execute(WatchForDisconnection.java:39)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
at org.gradle.launcher.daemon.server.exec.ResetDeprecationLogger.execute(ResetDeprecationLogger.java:29)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
at org.gradle.launcher.daemon.server.exec.RequestStopIfSingleUsedDaemon.execute(RequestStopIfSingleUsedDaemon.java:35)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
at org.gradle.launcher.daemon.server.exec.ForwardClientInput.lambda$execute$0(ForwardClientInput.java:40)
at org.gradle.internal.daemon.clientinput.ClientInputForwarder.forwardInput(ClientInputForwarder.java:80)
at org.gradle.launcher.daemon.server.exec.ForwardClientInput.execute(ForwardClientInput.java:37)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
at org.gradle.launcher.daemon.server.exec.LogAndCheckHealth.execute(LogAndCheckHealth.java:53)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
at org.gradle.launcher.daemon.server.exec.LogToClient.doBuild(LogToClient.java:63)
at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:37)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
at org.gradle.launcher.daemon.server.exec.EstablishBuildEnvironment.doBuild(EstablishBuildEnvironment.java:84)
at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:37)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
at org.gradle.launcher.daemon.server.exec.StartBuildOrRespondWithBusy$1.run(StartBuildOrRespondWithBusy.java:52)
at org.gradle.launcher.daemon.server.DaemonStateCoordinator.lambda$runCommand$0(DaemonStateCoordinator.java:321)
at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64)
at org.gradle.internal.concurrent.AbstractManagedExecutor$1.run(AbstractManagedExecutor.java:47)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
at java.base/java.lang.Thread.run(Thread.java:1583)
Caused by: org.gradle.api.internal.tasks.DefaultTaskContainer$TaskCreationException: Could not create task ':app:compileDebugKotlin'.
at org.gradle.api.internal.tasks.DefaultTaskContainer.taskCreationException(DefaultTaskContainer.java:729)
at org.gradle.api.internal.tasks.DefaultTaskContainer.access$600(DefaultTaskContainer.java:78)
at org.gradle.api.internal.tasks.DefaultTaskContainer$TaskCreatingProvider.domainObjectCreationException(DefaultTaskContainer.java:721)
at org.gradle.api.internal.DefaultNamedDomainObjectCollection$AbstractDomainObjectCreatingProvider.tryCreate(DefaultNamedDomainObjectCollection.java:1016)
at org.gradle.api.internal.tasks.DefaultTaskContainer$TaskCreatingProvider.access$1401(DefaultTaskContainer.java:668)
at org.gradle.api.internal.tasks.DefaultTaskContainer$TaskCreatingProvider$1.run(DefaultTaskContainer.java:694)
at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:29)
at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:26)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:66)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:59)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:166)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:59)
at org.gradle.internal.operations.DefaultBuildOperationRunner.run(DefaultBuildOperationRunner.java:47)
at org.gradle.api.internal.tasks.DefaultTaskContainer$TaskCreatingProvider.tryCreate(DefaultTaskContainer.java:690)
at org.gradle.api.internal.DefaultNamedDomainObjectCollection$AbstractDomainObjectCreatingProvider.calculateOwnValue(DefaultNamedDomainObjectCollection.java:990)
at org.gradle.api.internal.provider.AbstractMinimalProvider.calculateValue(AbstractMinimalProvider.java:115)
at org.gradle.api.internal.provider.FlatMapProvider.calculateOwnValue(FlatMapProvider.java:49)
at org.gradle.api.internal.provider.AbstractMinimalProvider.calculateOwnPresentValue(AbstractMinimalProvider.java:80)
at org.gradle.api.internal.provider.AbstractMinimalProvider.get(AbstractMinimalProvider.java:100)
at org.gradle.api.internal.provider.ProviderResolutionStrategy$2.resolve(ProviderResolutionStrategy.java:32)
at org.gradle.api.internal.file.collections.ProviderBackedFileCollection.visitChildren(ProviderBackedFileCollection.java:63)
at org.gradle.api.internal.file.CompositeFileCollection.visitContents(CompositeFileCollection.java:112)
at org.gradle.api.internal.file.AbstractFileCollection.visitStructure(AbstractFileCollection.java:361)
at org.gradle.api.internal.file.CompositeFileCollection.lambda$visitContents$0(CompositeFileCollection.java:112)
at org.gradle.api.internal.file.collections.UnpackingVisitor.add(UnpackingVisitor.java:76)
at org.gradle.api.internal.file.collections.DefaultConfigurableFileCollection$UnresolvedItemsCollector.visitContents(DefaultConfigurableFileCollection.java:635)
at org.gradle.api.internal.file.collections.DefaultConfigurableFileCollection.visitChildren(DefaultConfigurableFileCollection.java:448)
at org.gradle.api.internal.file.CompositeFileCollection.visitContents(CompositeFileCollection.java:112)
at org.gradle.api.internal.file.AbstractFileCollection.getFiles(AbstractFileCollection.java:124)
at kotlinx.kover.gradle.plugin.locators.JvmKt.extractJvmCompilation(Jvm.kt:32)
at kotlinx.kover.gradle.plugin.locators.JvmKt.jvmCompilations(Jvm.kt:20)
at kotlinx.kover.gradle.plugin.locators.AndroidKt.extractCompilation(Android.kt:100)
at kotlinx.kover.gradle.plugin.locators.AndroidKt.access$extractCompilation(Android.kt:1)
at kotlinx.kover.gradle.plugin.locators.AndroidKt$extractAndroidKit$compilations$1.call(Android.kt:49)
at kotlinx.kover.gradle.plugin.locators.AndroidKt$extractAndroidKit$compilations$1.call(Android.kt:48)
at org.gradle.api.internal.provider.DefaultProvider.calculateOwnValue(DefaultProvider.java:73)
at org.gradle.api.internal.provider.AbstractMinimalProvider.calculateValue(AbstractMinimalProvider.java:115)
at org.gradle.api.internal.provider.TransformBackedProvider.calculateOwnValue(TransformBackedProvider.java:81)
at org.gradle.api.internal.provider.AbstractMinimalProvider.calculateValue(AbstractMinimalProvider.java:115)
at org.gradle.api.internal.provider.TransformBackedProvider.calculateOwnValue(TransformBackedProvider.java:81)
at org.gradle.api.internal.provider.AbstractMinimalProvider.calculateOwnPresentValue(AbstractMinimalProvider.java:80)
at org.gradle.api.internal.provider.AbstractMinimalProvider.get(AbstractMinimalProvider.java:100)
at org.gradle.api.internal.tasks.DefaultTaskDependency.visitDependencies(DefaultTaskDependency.java:109)
at org.gradle.api.internal.tasks.CachingTaskDependencyResolveContext$TaskGraphImpl.getNodeValues(CachingTaskDependencyResolveContext.java:108)
at org.gradle.internal.graph.CachingDirectedGraphWalker$GraphWithEmptyEdges.getNodeValues(CachingDirectedGraphWalker.java:220)
at org.gradle.internal.graph.CachingDirectedGraphWalker.doSearch(CachingDirectedGraphWalker.java:128)
at org.gradle.internal.graph.CachingDirectedGraphWalker.findValues(CachingDirectedGraphWalker.java:80)
at org.gradle.api.internal.tasks.CachingTaskDependencyResolveContext.getDependencies(CachingTaskDependencyResolveContext.java:67)
... 147 more
Caused by: org.gradle.api.internal.tasks.DefaultTaskContainer$TaskCreationException: Could not create task ':app:kspDebugKotlin'.
at org.gradle.api.internal.tasks.DefaultTaskContainer.taskCreationException(DefaultTaskContainer.java:729)
at org.gradle.api.internal.tasks.DefaultTaskContainer.access$600(DefaultTaskContainer.java:78)
at org.gradle.api.internal.tasks.DefaultTaskContainer$TaskCreatingProvider.domainObjectCreationException(DefaultTaskContainer.java:721)
at org.gradle.api.internal.DefaultNamedDomainObjectCollection$AbstractDomainObjectCreatingProvider.tryCreate(DefaultNamedDomainObjectCollection.java:1016)
at org.gradle.api.internal.tasks.DefaultTaskContainer$TaskCreatingProvider.access$1401(DefaultTaskContainer.java:668)
at org.gradle.api.internal.tasks.DefaultTaskContainer$TaskCreatingProvider$1.run(DefaultTaskContainer.java:694)
at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:29)
at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:26)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:66)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:59)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:166)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:59)
at org.gradle.internal.operations.DefaultBuildOperationRunner.run(DefaultBuildOperationRunner.java:47)
at org.gradle.api.internal.tasks.DefaultTaskContainer$TaskCreatingProvider.tryCreate(DefaultTaskContainer.java:690)
at org.gradle.api.internal.DefaultNamedDomainObjectCollection$AbstractDomainObjectCreatingProvider.calculateOwnValue(DefaultNamedDomainObjectCollection.java:990)
at org.gradle.api.internal.provider.AbstractMinimalProvider.calculateValue(AbstractMinimalProvider.java:115)
at org.gradle.api.internal.provider.FlatMapProvider.calculateOwnValue(FlatMapProvider.java:49)
at org.gradle.api.internal.provider.AbstractMinimalProvider.calculateOwnPresentValue(AbstractMinimalProvider.java:80)
at org.gradle.api.internal.provider.AbstractMinimalProvider.get(AbstractMinimalProvider.java:100)
at org.gradle.api.internal.provider.ProviderResolutionStrategy$2.resolve(ProviderResolutionStrategy.java:32)
at org.gradle.util.internal.DeferredUtil.unpack(DeferredUtil.java:59)
at org.gradle.util.internal.DeferredUtil.unpack(DeferredUtil.java:38)
at org.gradle.api.internal.file.AbstractFileResolver.unpackAndParseNotation(AbstractFileResolver.java:93)
at org.gradle.api.internal.file.AbstractFileResolver.resolve(AbstractFileResolver.java:83)
at org.gradle.api.internal.file.AbstractFileResolver.resolve(AbstractFileResolver.java:57)
at org.gradle.api.internal.file.collections.DefaultConfigurableFileTree.getDir(DefaultConfigurableFileTree.java:101)
at org.jetbrains.kotlin.gradle.plugin.AndroidProjectHandler$postprocessVariant$2.execute(AndroidProjectHandler.kt:236)
at org.jetbrains.kotlin.gradle.plugin.AndroidProjectHandler$postprocessVariant$2.execute(AndroidProjectHandler.kt:234)
at org.gradle.api.internal.DefaultMutationGuard$1.execute(DefaultMutationGuard.java:66)
at org.gradle.api.internal.DefaultMutationGuard$1.execute(DefaultMutationGuard.java:66)
at org.gradle.internal.code.DefaultUserCodeApplicationContext$CurrentApplication$1.execute(DefaultUserCodeApplicationContext.java:124)
at org.gradle.api.internal.DefaultCollectionCallbackActionDecorator$BuildOperationEmittingAction$1.run(DefaultCollectionCallbackActionDecorator.java:109)
at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:29)
at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:26)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:66)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:59)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:166)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:59)
at org.gradle.internal.operations.DefaultBuildOperationRunner.run(DefaultBuildOperationRunner.java:47)
at org.gradle.api.internal.DefaultCollectionCallbackActionDecorator$BuildOperationEmittingAction.execute(DefaultCollectionCallbackActionDecorator.java:106)
at org.gradle.internal.ImmutableActionSet$SetWithManyActions.execute(ImmutableActionSet.java:330)
at org.gradle.api.internal.DefaultDomainObjectCollection.doAdd(DefaultDomainObjectCollection.java:280)
at org.gradle.api.internal.DefaultNamedDomainObjectCollection.doAdd(DefaultNamedDomainObjectCollection.java:126)
at org.gradle.api.internal.DefaultNamedDomainObjectCollection$AbstractDomainObjectCreatingProvider.tryCreate(DefaultNamedDomainObjectCollection.java:1010)
... 191 more
Caused by: java.lang.UnsupportedOperationException
at java.base/java.util.Collections$UnmodifiableCollection.add(Collections.java:1091)
at org.gradle.api.internal.file.collections.DefaultConfigurableFileCollection$UnresolvedItemsCollector.addItem(DefaultConfigurableFileCollection.java:684)
at org.gradle.api.internal.file.collections.DefaultConfigurableFileCollection$UnresolvedItemsCollector.plus(DefaultConfigurableFileCollection.java:666)
at org.gradle.api.internal.file.collections.DefaultConfigurableFileCollection$Configurer.from(DefaultConfigurableFileCollection.java:844)
at org.gradle.api.internal.file.collections.DefaultConfigurableFileCollection.lambda$from$0(DefaultConfigurableFileCollection.java:378)
at org.gradle.api.internal.file.collections.DefaultConfigurableFileCollection.withActualValue(DefaultConfigurableFileCollection.java:99)
at org.gradle.api.internal.file.collections.DefaultConfigurableFileCollection.from(DefaultConfigurableFileCollection.java:378)
at com.google.devtools.ksp.gradle.KspAATask$Companion$registerKspAATask$kspTaskProvider$1.invoke(KspAATask.kt:336)
at com.google.devtools.ksp.gradle.KspAATask$Companion$registerKspAATask$kspTaskProvider$1.invoke(KspAATask.kt:185)
at com.google.devtools.ksp.gradle.KspAATask$Companion.registerKspAATask$lambda$2(KspAATask.kt:185)
at org.gradle.api.internal.DefaultMutationGuard$1.execute(DefaultMutationGuard.java:66)
at org.gradle.api.internal.DefaultMutationGuard$1.execute(DefaultMutationGuard.java:66)
at org.gradle.internal.code.DefaultUserCodeApplicationContext$CurrentApplication$1.execute(DefaultUserCodeApplicationContext.java:124)
at org.gradle.api.internal.DefaultCollectionCallbackActionDecorator$BuildOperationEmittingAction$1.run(DefaultCollectionCallbackActionDecorator.java:109)
at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:29)
at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:26)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:66)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:59)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:166)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:59)
at org.gradle.internal.operations.DefaultBuildOperationRunner.run(DefaultBuildOperationRunner.java:47)
at org.gradle.api.internal.DefaultCollectionCallbackActionDecorator$BuildOperationEmittingAction.execute(DefaultCollectionCallbackActionDecorator.java:106)
at org.gradle.internal.ImmutableActionSet$SetWithManyActions.execute(ImmutableActionSet.java:330)
at org.gradle.api.internal.DefaultDomainObjectCollection.doAdd(DefaultDomainObjectCollection.java:280)
at org.gradle.api.internal.DefaultNamedDomainObjectCollection.doAdd(DefaultNamedDomainObjectCollection.java:126)
at org.gradle.api.internal.DefaultNamedDomainObjectCollection$AbstractDomainObjectCreatingProvider.tryCreate(DefaultNamedDomainObjectCollection.java:1010)
... 231 more
```

https://github.com/google/ksp/blob/046d27fed949c64b50964a277309545847322ba3/gradle-plugin/src/main/kotlin/com/google/devtools/ksp/gradle/KspAATask.kt#L336

If we backtrack a bit, we can see that this is inside:
```kotlin
val kspTaskName = kotlinCompileProvider.name.replaceFirst("compile", "ksp")
project.tasks.register(kspTaskName, KspAATask::class.java) { kspAATask ->
...
}
```

So to sum up:
1. We have some tasks (Kotlin/Java) that compile classes.
2. We have a task that generates more Kotlin classes (KSP).
(1) will be wired to depend on this task.
3. We have a third party that enumerates the classes.

Due to the way Gradle is lazy, while (3) is resolving (1), Gradle will first create (2), which mutates the file collection of `classesDirs` and bang!

## Cause

Scrolling through the [2.0.3 .. 2.0.4 diff]() I'm suspecting https://github.com/google/ksp/commit/8c02de73198e184a645344b63fdd307db9afed8a to be the trigger for this.

## Proposal
Move the mutation of `classesDirs` outside of the task creation. All the dependencies are available from the function parameters.
```kotlin
val classOutputDir = KspGradleSubplugin.getKspClassOutputDir(project, sourceSetName, target)
val compilerOptions = kotlinCompilation.compilerOptions.options
if (compilerOptions is KotlinJvmCompilerOptions) {
// Don't support binary generation for non-JVM platforms yet.
// FIXME: figure out how to add user generated libraries.
kotlinCompilation.output.classesDirs.from(classOutputDir)
}
project.tasks.register(kspTaskName, KspAATask::class.java) { kspAATask ->
...
}
```
I have confirmed this working locally, but not sure what other side effects it might have.
I think the original https://github.com/google/ksp/commit/afafe4f211d7fe5a56fdf3cb4040805b27ff3bf2 shows that these are kind of independent and added after the fact.

Clone the referenced TWiStErRob repro at ksp/classesDirs-ConcurrentModificationException and run `gradlew koverXmlReport` with `-S` to reproduce the failure. Start by tracing the output-class dependency resolution indicated by the stack trace; done means the command no longer fails with ConcurrentModificationException.

Written by the indexing model from the issue text.