Id fields duplicates for domain inheritance

[demon101]

in case of inheritance all classes in the hierarchy has id fields.
For AccessType.PROPERTY doesn't bring any bugs. All side effects corrected by method overriding.
But for GORM 6.1 AccessType.FIELD used by default. At the result, some strange bugs occur:

Caused by: java.lang.NullPointerException: null
at org.hibernate.type.descriptor.java.AbstractTypeDescriptor.extractHashCode(AbstractTypeDescriptor.java:65)
at org.hibernate.type.AbstractStandardBasicType.getHashCode(AbstractStandardBasicType.java:185)
at org.hibernate.type.AbstractStandardBasicType.getHashCode(AbstractStandardBasicType.java:189)
at org.hibernate.type.EntityType.getHashCode(EntityType.java:355)
at org.hibernate.type.ComponentType.getHashCode(ComponentType.java:241)
at org.hibernate.engine.spi.EntityKey.generateHashCode(EntityKey.java:59)
at org.hibernate.engine.spi.EntityKey.(EntityKey.java:54)
at org.hibernate.internal.AbstractSessionImpl.generateEntityKey(AbstractSessionImpl.java:338)
at org.hibernate.engine.internal.StatefulPersistenceContext.getDatabaseSnapshot(StatefulPersistenceContext.java:308)
at org.hibernate.engine.internal.ForeignKeys.isTransient(ForeignKeys.java:238)
at org.hibernate.event.internal.AbstractSaveEventListener.getEntityState(AbstractSaveEventListener.java:499)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:83)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:73)
at org.grails.orm.hibernate.support.ClosureEventTriggeringInterceptor.onSaveOrUpdate(ClosureEventTriggeringInterceptor.java:126)
at org.hibernate.internal.SessionImpl.fireSaveOrUpdate(SessionImpl.java:651)
at org.hibernate.internal.SessionImpl.saveOrUpdate(SessionImpl.java:643)
at org.hibernate.internal.SessionImpl.saveOrUpdate(SessionImpl.java:638)
at org.grails.orm.hibernate.AbstractHibernateGormInstanceApi$_performSave_closure3.doCall(AbstractHibernateGormInstanceApi.groovy:247)
at sun.reflect.GeneratedMethodAccessor566.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springsource.loaded.ri.ReflectiveInterceptor.jlrMethodInvoke(ReflectiveInterceptor.java:1427)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:98)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1225)
at groovy.lang.ExpandoMetaClass.invokeMethod(ExpandoMetaClass.java:1125)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1034)
at groovy.lang.Closure.call(Closure.java:418)
at org.codehaus.groovy.runtime.ConvertedClosure.invokeCustom(ConvertedClosure.java:54)
at org.codehaus.groovy.runtime.ConversionHandler.invoke(ConversionHandler.java:124)
at com.sun.proxy.$Proxy138.doInHibernate(Unknown Source)

The problem is:
id field of child filled during saving, but persister.getIdentifier( x ) looking on id field of parent.

Childe id field looks excessive and shouldn't be added.

def o = new Child().save()
print o.id // some number
print ((Parent) o).id // null

Bug can be solved either by filling by same value parent.id or by removing of duplicate field of childe

Task List

• Steps to reproduce provided
• Stacktrace (if present) provided
• Example that reproduces the problem uploaded to Github
• Full description of the issue provided (see below)

Steps to Reproduce

1. TODO
2. TODO
3. TODO

Expected Behaviour

Tell us what should happen

Actual Behaviour

Tell us what happens instead

Environment Information

• Operating System: TODO
• GORM Version: 6.1.11
• Grails Version (if using Grails): 3.3.9
• JDK Version: TODO

Example Application

• TODO: link to github repository with example that reproduces the issue

[demon101]

should be handled here https://github.com/grails/grails-data-mapping/blob/master/grails-datastore-gorm/src/main/groovy/org/grails/compiler/gorm/GormEntityTransformation.groovy#L459
but may be a bug in Grails
see https://github.com/grails/grails-core/blob/master/grails-core/src/main/groovy/org/grails/compiler/injection/DefaultGrailsDomainClassInjector.java#L222
it is in one of those two places

[demon101]

First of all, both classes method executed. DefaultGrailsDomainClassInjector first, GormEntityTransformation second.

Problem in line
ClassNode parent = GrailsASTUtils.getFurthestUnresolvedParent(classNode);

For child class it returns same class node, not a parent. At result, id will be inserted in child

In my example, parent is abstract. getFurthestUnresolvedParent has
!Modifier.isAbstract(parent.getModifiers()) check.

[demon101]

The issue can be closed after apache/grails-core#11254

[demon101]

Fix merged, will be part of Grails 3.3.10