HHH-18217 Properly handle empty value bindings for merge operations

Author: beikov

hibernate-core/src/main/java/org/hibernate/StaleStateException.java

@@ -26,4 +26,15 @@ public class StaleStateException extends HibernateException {
 	public StaleStateException(String message) {
 		super( message );
 	}
+
+	/**
+	 * Constructs a {@code StaleStateException} using the supplied message
+	 * and cause.
+	 *
+	 * @param message The message explaining the exception condition
+	 * @param cause An exception to wrap
+	 */
+	public StaleStateException(String message, Exception cause) {
+		super( message, cause );
+	}
 }

hibernate-core/src/main/java/org/hibernate/dialect/SqlAstTranslatorWithMerge.java

@@ -11,6 +11,7 @@
 import org.hibernate.engine.spi.SessionFactoryImplementor;
 import org.hibernate.internal.util.StringHelper;
 import org.hibernate.sql.ast.spi.AbstractSqlAstTranslator;
+import org.hibernate.jdbc.Expectation;
 import org.hibernate.sql.ast.tree.Statement;
 import org.hibernate.sql.exec.spi.JdbcOperation;
 import org.hibernate.sql.model.ast.ColumnValueBinding;
@@ -46,6 +47,10 @@ public MergeOperation createMergeOperation(OptionalTableUpdate optionalTableUpda
 				optionalTableUpdate.getMutatingTable().getTableMapping(),
 				optionalTableUpdate.getMutationTarget(),
 				getSql(),
+				// Without value bindings, the upsert may have an update count of 0
+				optionalTableUpdate.getValueBindings().isEmpty()
+						? new Expectation.OptionalRowCount()
+						: new Expectation.RowCount(),
 				getParameterBinders()
 		);
 	}
@@ -228,16 +233,18 @@ protected void renderMergeUpdate(OptionalTableUpdate optionalTableUpdate) {
 		final List<ColumnValueBinding> valueBindings = optionalTableUpdate.getValueBindings();
 		final List<ColumnValueBinding> optimisticLockBindings = optionalTableUpdate.getOptimisticLockBindings();
 
-		renderWhenMatched( optimisticLockBindings );
-		appendSql( " then update set " );
-		for ( int i = 0; i < valueBindings.size(); i++ ) {
-			final ColumnValueBinding binding = valueBindings.get( i );
-			if ( i > 0 ) {
-				appendSql( ", " );
+		if ( !valueBindings.isEmpty() ) {
+			renderWhenMatched( optimisticLockBindings );
+			appendSql( " then update set " );
+			for ( int i = 0; i < valueBindings.size(); i++ ) {
+				final ColumnValueBinding binding = valueBindings.get( i );
+				if ( i > 0 ) {
+					appendSql( ", " );
+				}
+				binding.getColumnReference().appendColumnForWrite( this, null );
+				appendSql( "=" );
+				binding.getColumnReference().appendColumnForWrite( this, "s" );
 			}
-			binding.getColumnReference().appendColumnForWrite( this, null );
-			appendSql( "=" );
-			binding.getColumnReference().appendColumnForWrite( this, "s" );
 		}
 	}
 

hibernate-core/src/main/java/org/hibernate/dialect/SqlAstTranslatorWithUpsert.java

@@ -9,6 +9,7 @@
 import java.util.List;
 
 import org.hibernate.engine.spi.SessionFactoryImplementor;
+import org.hibernate.jdbc.Expectation;
 import org.hibernate.persister.entity.mutation.EntityTableMapping;
 import org.hibernate.sql.ast.spi.AbstractSqlAstTranslator;
 import org.hibernate.sql.ast.tree.Statement;
@@ -39,6 +40,10 @@ public MutationOperation createMergeOperation(OptionalTableUpdate optionalTableU
 				optionalTableUpdate.getMutatingTable().getTableMapping(),
 				optionalTableUpdate.getMutationTarget(),
 				getSql(),
+				// Without value bindings, the upsert may have an update count of 0
+				optionalTableUpdate.getValueBindings().isEmpty()
+						? new Expectation.OptionalRowCount()
+						: new Expectation.RowCount(),
 				getParameterBinders()
 		);
 
@@ -193,17 +198,19 @@ protected void renderMergeUpdate(OptionalTableUpdate optionalTableUpdate) {
 		final List<ColumnValueBinding> valueBindings = optionalTableUpdate.getValueBindings();
 		final List<ColumnValueBinding> optimisticLockBindings = optionalTableUpdate.getOptimisticLockBindings();
 
-		appendSql( " when matched then update set " );
-		for ( int i = 0; i < valueBindings.size(); i++ ) {
-			final ColumnValueBinding binding = valueBindings.get( i );
-			if ( i > 0 ) {
-				appendSql( ", " );
+		if ( !valueBindings.isEmpty() ) {
+			appendSql( " when matched then update set " );
+			for ( int i = 0; i < valueBindings.size(); i++ ) {
+				final ColumnValueBinding binding = valueBindings.get( i );
+				if ( i > 0 ) {
+					appendSql( ", " );
+				}
+				binding.getColumnReference().appendColumnForWrite( this, "t" );
+				appendSql( "=" );
+				binding.getColumnReference().appendColumnForWrite( this, "s" );
 			}
-			binding.getColumnReference().appendColumnForWrite( this, "t" );
-			appendSql( "=" );
-			binding.getColumnReference().appendColumnForWrite( this, "s" );
+			renderMatchedWhere( optimisticLockBindings );
 		}
-		renderMatchedWhere( optimisticLockBindings );
 	}
 
 	private void renderMatchedWhere(List<ColumnValueBinding> optimisticLockBindings) {