[hibernate-dev] HHH-8999/HHH-10413 and Comparable IDs

ExecutableList#add attempts to keep track of whether the Executable objects are sorted. [1] Except for entity insert actions (which use InsertActionSorter), ExecutableList#add uses the following to determine if adding the current Executable to the end invalidates the sort: if ( previousLast != null && previousLast.compareTo( executable ) > 0 ) { sorted = false; } EntityAction#compareTo compares the IDs for the current and previous EntityAction if they have different entity names; similarly, CollectionAction compares the collection keys for the current and previous CollectionAction if they have different entity names. In most cases, the ID class implements Comparable, although I don't know of any requirement that says this needs to be true. This breaks down when a byte[] ID is used as described by HHH-8999. The reason is that AbstractTypeDescriptor#comparator is null because it is assigned like this: this.comparator = Comparable.class.isAssignableFrom( type ) ? (Comparator<T>) ComparableComparator.INSTANCE : null; PrimitiveByteArrayTypeDescriptor does not override AbstractTypeDescriptor#getComparator, so null is returned ultimately causing a NullPointerException in AbstractStandardBasicType#compare: public final int compare(Object x, Object y) { return javaTypeDescriptor.getComparator().compare( (T) x, (T) y ); } The same happens for PrimitiveCharacterArrayTypeDescriptor, ByteArrayTypeDescriptor, and CharacterArrayTypeDescriptor. Are there others? According to HHH-10413, this also affects version attributes. Here are a couple of alternatives: A) create comparators for PrimitiveCharacterArrayTypeDescriptor, ByteArrayTypeDescriptor, and CharacterArrayTypeDescriptor. B) Change AbstractTypeDescriptor#comparator to: this.comparator = Comparable.class.isAssignableFrom( type ) ? (Comparator<T>) ComparableComparator.INSTANCE : IncomparableComparator.INSTANCE; IncomparableComparator#compare always returns 0, so that comparison would never invalidate the sort. Does it make sense to sort Executable objects by an ID or collection key that is an array? In other words, would such IDs be generated in a natural order? If not, I think B) makes more sense. Thoughts? Thanks, Gail [1] https://github.com/hibernate/hibernate-orm/blob/master/hibernate-core/src...