HHH-17804 roll back change to semantics of 'null in ()'

It turns out that SQL databases (IMO wrongly) treat the expression
'null in (select 1 where false)' as false instead of null. And as
of JPA 3.2, we're free to interpret 'null in ()' consistently with
that, which we should do.

So my change made things worse rather than better.

Signed-off-by: Gavin King <gavin@hibernate.org>

hibernate-core/src/main/java/org/hibernate/persister/entity/AbstractEntityPersister.java

@@ -3206,7 +3206,7 @@ public abstract class AbstractEntityPersister
 			Map<String, EntityNameUse> entityNameUses,
 			MappingMetamodelImplementor mappingMetamodel,
 			String alias) {
-		final InFragment frag = new InFragment( false );
+		final InFragment frag = new InFragment();
 		if ( isDiscriminatorFormula() ) {
 			frag.setFormula( alias, getDiscriminatorFormulaTemplate() );
 		}

hibernate-core/src/main/java/org/hibernate/sql/InFragment.java

@@ -21,15 +21,10 @@ import org.hibernate.internal.util.StringHelper;
 @Internal
 public class InFragment {
 
-	public InFragment(boolean columnCanBeNull) {
-		this.columnCanBeNull = columnCanBeNull;
-	}
-
 	public static final String NULL = "null";
 	public static final String NOT_NULL = "not null";
 
 	protected String columnName;
-	protected boolean columnCanBeNull;
 	protected List<Object> values = new ArrayList<>();
 
 	/**
@@ -71,15 +66,7 @@ public class InFragment {
 
 		switch ( values.size() ) {
 			case 0: {
-				if ( columnCanBeNull ) {
+				return "0=1";
-					return buf.append( "(1 = case when " )
-							.append( columnName )
-							.append(" is not null then 0 end)")
-							.toString();
-				}
-				else {
-					return "0=1";
-				}
 			}
 			case 1: {
 				Object value = values.get( 0 );

hibernate-core/src/main/java/org/hibernate/sql/ast/spi/AbstractSqlAstTranslator.java

@@ -7641,7 +7641,7 @@ public abstract class AbstractSqlAstTranslator<T extends JdbcOperation> implemen
 	public void visitInListPredicate(InListPredicate inListPredicate) {
 		final List<Expression> listExpressions = inListPredicate.getListExpressions();
 		if ( listExpressions.isEmpty() ) {
-			emptyInList( inListPredicate );
+			appendSql( "1=" + ( inListPredicate.isNegated() ? "1" : "0" ) );
 			return;
 		}
 		Function<Expression, Expression> itemAccessor = Function.identity();
@@ -7748,16 +7748,6 @@ public abstract class AbstractSqlAstTranslator<T extends JdbcOperation> implemen
 		}
 	}
 
-	protected void emptyInList(InListPredicate inListPredicate) {
-		appendSql("(");
-		appendSql( inListPredicate.isNegated() ? "0" : "1" );
-		appendSql(" = case when ");
-		inListPredicate.getTestExpression().accept( this );
-		appendSql( " is not null then 0");
-//		dialect.appendBooleanValueString( this, inListPredicate.isNegated() );
-		appendSql(" end)");
-	}
-
 	private void appendInClauseSeparator(InListPredicate inListPredicate) {
 		appendSql( CLOSE_PARENTHESIS );
 		appendSql( inListPredicate.isNegated() ? " and " : " or " );

hibernate-core/src/test/java/org/hibernate/orm/test/jpa/criteria/basic/PredicateTest.java

@@ -31,6 +31,7 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 /**
@@ -334,7 +335,7 @@ public class PredicateTest extends AbstractMetamodelSpecificTest {
 		CriteriaQuery<Order> orderCriteria = builder.createQuery( Order.class );
 		Root<Order> orderRoot = orderCriteria.from( Order.class );
 		orderCriteria.select( orderRoot );
-		orderCriteria.where( builder.in( orderRoot.get("creditCard") ) );
+		orderCriteria.where( builder.in( orderRoot.get("id") ) );
 
 		List<Order> orders = em.createQuery( orderCriteria ).getResultList();
 		assertTrue( orders.isEmpty() );
@@ -350,10 +351,10 @@ public class PredicateTest extends AbstractMetamodelSpecificTest {
 		CriteriaQuery<Order> orderCriteria = builder.createQuery( Order.class );
 		Root<Order> orderRoot = orderCriteria.from( Order.class );
 		orderCriteria.select( orderRoot );
-		orderCriteria.where( builder.in( orderRoot.get("creditCard") ).not() );
+		orderCriteria.where( builder.in( orderRoot.get("id") ).not() );
 
 		List<Order> orders = em.createQuery( orderCriteria ).getResultList();
-		assertTrue( orders.isEmpty() );
+		assertFalse( orders.isEmpty() );
 		em.getTransaction().commit();
 		em.close();
 	}