[BUG] Using OpenApiNormalizer in openapi-generator-cli runs into memory errors (spring boot 3)

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• [ yes] Have you validated the input using an OpenAPI validator (example)?
• [ yes] Have you tested with the latest master to confirm the issue still exists?
• [ yes] Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':openApiGenerate'. at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.lambda$executeIfValid$1(ExecuteActionsTaskExecuter.java:142) at org.gradle.internal.Try$Failure.ifSuccessfulOrElse(Try.java:282) at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeIfValid(ExecuteActionsTaskExecuter.java:140) at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:128) at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:77) at org.gradle.api.internal.tasks.execution.FinalizePropertiesTaskExecuter.execute(FinalizePropertiesTaskExecuter.java:46) at org.gradle.api.internal.tasks.execution.ResolveTaskExecutionModeExecuter.execute(ResolveTaskExecutionModeExecuter.java:51) at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:57) at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:57) at org.gradle.api.internal.tasks.execution.CatchExceptionTaskExecuter.execute(CatchExceptionTaskExecuter.java:36) at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.executeTask(EventFiringTaskExecuter.java:77) at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.call(EventFiringTaskExecuter.java:55) at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.call(EventFiringTaskExecuter.java:52) at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:204) at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:199) at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:66) at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:59) at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:157) at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:59) at org.gradle.internal.operations.DefaultBuildOperationRunner.call(DefaultBuildOperationRunner.java:53) at org.gradle.internal.operations.DefaultBuildOperationExecutor.call(DefaultBuildOperationExecutor.java:73) at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter.execute(EventFiringTaskExecuter.java:52) at org.gradle.execution.plan.LocalTaskNodeExecutor.execute(LocalTaskNodeExecutor.java:69) at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$InvokeNodeExecutorsAction.execute(DefaultTaskExecutionGraph.java:322) at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$InvokeNodeExecutorsAction.execute(DefaultTaskExecutionGraph.java:309) at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$BuildOperationAwareExecutionAction.execute(DefaultTaskExecutionGraph.java:302) at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$BuildOperationAwareExecutionAction.execute(DefaultTaskExecutionGraph.java:288) at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.execute(DefaultPlanExecutor.java:462) at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.run(DefaultPlanExecutor.java:379) at org.gradle.execution.plan.DefaultPlanExecutor.process(DefaultPlanExecutor.java:115) at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph.executeWithServices(DefaultTaskExecutionGraph.java:135) at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph.execute(DefaultTaskExecutionGraph.java:120) at org.gradle.execution.SelectedTaskExecutionAction.execute(SelectedTaskExecutionAction.java:35) at org.gradle.execution.DryRunBuildExecutionAction.execute(DryRunBuildExecutionAction.java:51) at org.gradle.execution.BuildOperationFiringBuildWorkerExecutor$ExecuteTasks.call(BuildOperationFiringBuildWorkerExecutor.java:54) at org.gradle.execution.BuildOperationFiringBuildWorkerExecutor$ExecuteTasks.call(BuildOperationFiringBuildWorkerExecutor.java:43) at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:204) at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:199) at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:66) at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:59) at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:157) at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:59) at org.gradle.internal.operations.DefaultBuildOperationRunner.call(DefaultBuildOperationRunner.java:53) at org.gradle.internal.operations.DefaultBuildOperationExecutor.call(DefaultBuildOperationExecutor.java:73) at org.gradle.execution.BuildOperationFiringBuildWorkerExecutor.execute(BuildOperationFiringBuildWorkerExecutor.java:40) at org.gradle.internal.build.DefaultBuildLifecycleController.lambda$executeTasks$6(DefaultBuildLifecycleController.java:167) at org.gradle.internal.model.StateTransitionController.doTransition(StateTransitionController.java:247) at org.gradle.internal.model.StateTransitionController.lambda$tryTransition$7(StateTransitionController.java:174) at org.gradle.internal.work.DefaultSynchronizer.withLock(DefaultSynchronizer.java:44) at org.gradle.internal.model.StateTransitionController.tryTransition(StateTransitionController.java:174) at org.gradle.internal.build.DefaultBuildLifecycleController.executeTasks(DefaultBuildLifecycleController.java:167) at org.gradle.internal.build.DefaultBuildWorkGraphController$DefaultBuildWorkGraph.runWork(DefaultBuildWorkGraphController.java:190) at org.gradle.internal.work.DefaultWorkerLeaseService.withLocks(DefaultWorkerLeaseService.java:249) at org.gradle.internal.work.DefaultWorkerLeaseService.runAsWorkerThread(DefaultWorkerLeaseService.java:109) at org.gradle.composite.internal.DefaultBuildController.doRun(DefaultBuildController.java:172) at org.gradle.composite.internal.DefaultBuildController.access$000(DefaultBuildController.java:47) at org.gradle.composite.internal.DefaultBuildController$BuildOpRunnable.run(DefaultBuildController.java:191) at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64) at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:49) Caused by: java.lang.OutOfMemoryError: Java heap space at org.openapitools.codegen.DefaultCodegen.updateAllModels(DefaultCodegen.java:632) at org.openapitools.codegen.DefaultGenerator.generateModels(DefaultGenerator.java:529) at org.openapitools.codegen.DefaultGenerator.generate(DefaultGenerator.java:946) at org.openapitools.generator.gradle.plugin.tasks.GenerateTask.doWork(GenerateTask.kt:841) 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 org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:125) at org.gradle.api.internal.project.taskfactory.StandardTaskAction.doExecute(StandardTaskAction.java:58) at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:51) at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:29) at org.gradle.api.internal.tasks.execution.TaskExecution$3.run(TaskExecution.java:236) 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:157) at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:59) at org.gradle.internal.operations.DefaultBuildOperationRunner.run(DefaultBuildOperationRunner.java:47) at org.gradle.internal.operations.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:68) at org.gradle.api.internal.tasks.execution.TaskExecution.executeAction(TaskExecution.java:221) at org.gradle.api.internal.tasks.execution.TaskExecution.executeActions(TaskExecution.java:204) at org.gradle.api.internal.tasks.execution.TaskExecution.executeWithPreviousOutputFiles(TaskExecution.java:187) at org.gradle.api.internal.tasks.execution.TaskExecution.execute(TaskExecution.java:165) at org.gradle.internal.execution.steps.ExecuteStep.executeInternal(ExecuteStep.java:89) at org.gradle.internal.execution.steps.ExecuteStep.access$000(ExecuteStep.java:40)

openapi-generator version

6.6.0

OpenAPI declaration file content or url

Cannot provide it. It is 2000+ lines
-->

Generation Details

Using the normalizer gives a heap error. Not using it generates code but it is incorrect

Steps to reproduce

Running from gradle plugin and adding the open-api normalizer : { REF_AS_PARENT_IN_ALL_OF : true}

Related issues/PRs

https://github.com/OpenAPITools/openapi-generator/issues/15939

A similar issue was closed without any further explanations.

Start by examining DefaultCodegen.updateAllModels and DefaultGenerator.generateModels from the reported stack trace, then reproduce the Gradle generation with the OpenAPI normalizer setting REF_AS_PARENT_IN_ALL_OF: true. The issue lacks the 2,000-line specification and a complete reproduction, so confirming the heap failure and defining done requires obtaining a representative input and verifying generated output remains correct.