Illegal reuse of criteria for count()-operator

[julgus]

Describe the bug
When performing repeated .count() queries, an exception is thrown. This seems to be related to differences between Hibernate 5 and 6, and how JPAStreamer reuses certain Criteria objects when creating the queries.

Expected behavior
The query should execute without exceptions.

Actual behavior
The query yields an exception, see below.

How To Reproduce
Performing the following test reveals the exception:

    @Test
    void countTest() {
        final List<Film> collect = jpaStreamer.stream(Film.class).collect(Collectors.toList());
        
        final long expected = collect.stream()
                .filter(f -> f.getTitle().startsWith("A"))
                .count(); 
        
        final long actual = jpaStreamer.stream(Film.class)
                .filter(Film$.title.startsWith("A"))
                .count(); 
        
        assertEquals(expected, actual);
    }

Exception:

java.lang.IllegalArgumentException: Already registered a copy: SqmBasicValuedSimplePath(com.speedment.jpastreamer.integration.test.model.Film(1295155256344291).title)

	at org.hibernate.query.sqm.tree.SqmCopyContext$1.registerCopy(SqmCopyContext.java:33)
	at org.hibernate.query.sqm.tree.domain.SqmBasicValuedSimplePath.copy(SqmBasicValuedSimplePath.java:53)
	at org.hibernate.query.sqm.tree.domain.SqmBasicValuedSimplePath.copy(SqmBasicValuedSimplePath.java:26)
	at org.hibernate.query.sqm.tree.predicate.SqmLikePredicate.copy(SqmLikePredicate.java:90)
	at org.hibernate.query.sqm.tree.predicate.SqmLikePredicate.copy(SqmLikePredicate.java:19)
	at org.hibernate.query.sqm.tree.predicate.SqmWhereClause.copy(SqmWhereClause.java:33)
	at org.hibernate.query.sqm.tree.select.SqmQuerySpec.copy(SqmQuerySpec.java:104)
...

Build tool
e.g. Maven 3.9.0

JPAStreamer version
e.g. JPAStreamer 3.0.2

JPA Provider
e.g. Hibernate 6.0.2.Final

Java Version
e.g. Java 11.0.17

Additional context
The thread that potentially explains the issue: https://hibernate.atlassian.net/browse/HHH-15951?jql=project%20%3D%20HHH%20AND%20component%20%3D%20hibernate-entitymanager%20AND%20resolution%20%3D%20Unresolved%20AND%20fixVersion%20is%20EMPTY%20ORDER%20BY%20priority%20DESC.

[julgus]

The issue is how we copy restrictions from the original Criteria when building the count Criteria. These restrictions are associated with a certain Path element that cannot be reused from one Criteria to another.

if (criteriaQuery.getRestriction() != null) {
            countQuery.where(criteriaQuery.getRestriction());
}

I fixed it by recreating the predicate from the internal pipeline. This adds a bit of redundant work but seems like the simplest solution at this point.

if (!filters.isEmpty()) {
    // There can only be one JPAStreamer filter after the filter merge (see FilterCriteriaModifier). 
    IntermediateOperation<?, ?> filter = filters.stream().findFirst().get();
    this.<T>getPredicate(filter).ifPresent(speedmentPredicate -> {
        final Predicate predicate = predicateFactory.createPredicate(countCriteria, speedmentPredicate);
        countQuery.where(predicate);
    });
}