Убрать костыль из ProgramExercise

[d-r-q]

Из-за, по видимому, бага в SDJ в модели нельзя использовать дата классы с единственным свойством, типа AggregateReference:

Попытка сохранить такой объект такого класса:

@Table("program_exercises")
data class ProgramExercise(
    val exerciseRef: AggregateReference<Exercise, Long>,
)

Приводит к

java.lang.IndexOutOfBoundsException: Index 0 out of bounds for length 0
	at java.base/jdk.internal.util.Preconditions.outOfBounds(Preconditions.java:100)
	at java.base/jdk.internal.util.Preconditions.outOfBoundsCheckIndex(Preconditions.java:106)
	at java.base/jdk.internal.util.Preconditions.checkIndex(Preconditions.java:302)
	at java.base/java.util.Objects.checkIndex(Objects.java:385)
	at java.base/java.util.ArrayList.get(ArrayList.java:427)
	at org.springframework.data.mapping.model.KotlinCopyMethod.shouldUsePublicCopyMethod(KotlinCopyMethod.java:177)
	at org.springframework.data.mapping.model.ClassGeneratingPropertyAccessorFactory$PropertyAccessorClassGenerator.visitKotlinCopy(ClassGeneratingPropertyAccessorFactory.java:1109)
	at org.springframework.data.mapping.model.ClassGeneratingPropertyAccessorFactory$PropertyAccessorClassGenerator.visitSetProperty0(ClassGeneratingPropertyAccessorFactory.java:1033)
	at org.springframework.data.mapping.model.ClassGeneratingPropertyAccessorFactory$PropertyAccessorClassGenerator.visitSetPropertySwitch(ClassGeneratingPropertyAccessorFactory.java:1005)
	at org.springframework.data.mapping.model.ClassGeneratingPropertyAccessorFactory$PropertyAccessorClassGenerator.visitSetProperty(ClassGeneratingPropertyAccessorFactory.java:955)
	at org.springframework.data.mapping.model.ClassGeneratingPropertyAccessorFactory$PropertyAccessorClassGenerator.generateBytecode(ClassGeneratingPropertyAccessorFactory.java:369)
	at org.springframework.data.mapping.model.ClassGeneratingPropertyAccessorFactory$PropertyAccessorClassGenerator.generateCustomAccessorClass(ClassGeneratingPropertyAccessorFactory.java:344)
	at org.springframework.data.mapping.model.ClassGeneratingPropertyAccessorFactory.createAccessorClass(ClassGeneratingPropertyAccessorFactory.java:210)
	at org.springframework.data.mapping.model.ClassGeneratingPropertyAccessorFactory.potentiallyCreateAndRegisterPersistentPropertyAccessorClass(ClassGeneratingPropertyAccessorFactory.java:196)
	at org.springframework.data.mapping.model.ClassGeneratingPropertyAccessorFactory.getPropertyAccessor(ClassGeneratingPropertyAccessorFactory.java:97)
	at org.springframework.data.mapping.model.InstantiationAwarePropertyAccessorFactory.lambda$getPropertyAccessor$0(InstantiationAwarePropertyAccessorFactory.java:42)
	at org.springframework.data.mapping.model.InstantiationAwarePropertyAccessor.getProperty(InstantiationAwarePropertyAccessor.java:123)
	at org.springframework.data.jdbc.core.convert.SqlParametersFactory.lambda$getParameterSource$2(SqlParametersFactory.java:265)
	at org.springframework.data.mapping.PersistentEntity.lambda$doWithAll$0(PersistentEntity.java:299)
	at org.springframework.data.mapping.model.BasicPersistentEntity.doWithAssociations(BasicPersistentEntity.java:317)
	at org.springframework.data.mapping.PersistentEntity.doWithAll(PersistentEntity.java:298)
	at org.springframework.data.jdbc.core.convert.SqlParametersFactory.getParameterSource(SqlParametersFactory.java:247)
	at org.springframework.data.jdbc.core.convert.SqlParametersFactory.forInsert(SqlParametersFactory.java:83)
	at org.springframework.data.jdbc.core.convert.DefaultDataAccessStrategy.lambda$insert$0(DefaultDataAccessStrategy.java:119)
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:197)
	at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1708)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:575)
	at java.base/java.util.stream.AbstractPipeline.evaluateToArrayNode(AbstractPipeline.java:260)
	at java.base/java.util.stream.ReferencePipeline.toArray(ReferencePipeline.java:616)
	at org.springframework.data.jdbc.core.convert.DefaultDataAccessStrategy.insert(DefaultDataAccessStrategy.java:121)
	at org.springframework.data.jdbc.core.JdbcAggregateChangeExecutionContext.executeBatchInsert(JdbcAggregateChangeExecutionContext.java:117)
	at org.springframework.data.jdbc.core.AggregateChangeExecutor.execute(AggregateChangeExecutor.java:91)
	at org.springframework.data.jdbc.core.AggregateChangeExecutor.lambda$executeSave$0(AggregateChangeExecutor.java:61)
	at org.springframework.data.relational.core.conversion.BatchedActions$InsertCombiner.lambda$forEach$2(BatchedActions.java:170)
	at java.base/java.util.HashMap.forEach(HashMap.java:1429)
	at org.springframework.data.relational.core.conversion.BatchedActions$InsertCombiner.lambda$forEach$3(BatchedActions.java:170)
	at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:184)
	at java.base/java.util.stream.SortedOps$SizedRefSortingSink.end(SortedOps.java:357)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:510)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
	at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
	at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:596)
	at org.springframework.data.relational.core.conversion.BatchedActions$InsertCombiner.forEach(BatchedActions.java:169)
	at org.springframework.data.relational.core.conversion.BatchedActions.forEach(BatchedActions.java:79)
	at org.springframework.data.relational.core.conversion.SaveBatchingAggregateChange.forEachAction(SaveBatchingAggregateChange.java:77)
	at org.springframework.data.jdbc.core.AggregateChangeExecutor.executeSave(AggregateChangeExecutor.java:61)
	at org.springframework.data.jdbc.core.JdbcAggregateTemplate.performSave(JdbcAggregateTemplate.java:491)
	at org.springframework.data.jdbc.core.JdbcAggregateTemplate.save(JdbcAggregateTemplate.java:168)
	at org.springframework.data.jdbc.repository.support.SimpleJdbcRepository.save(SimpleJdbcRepository.java:68)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580

При том, проблему решает:

1. Удаление data
2. Замена AggregateReference на Long
3. Добавление любого другого поля