Expression#as() broke since Hibernate 6.6.0

src/main/java/org/omnifaces/persistence/JPA.java

@@ -16,6 +16,8 @@
 import static java.util.stream.Collectors.toList;
 import static org.omnifaces.persistence.Database.POSTGRESQL;
 import static org.omnifaces.persistence.Provider.HIBERNATE;
+import static org.omnifaces.utils.reflect.Reflections.findClass;
+import static org.omnifaces.utils.reflect.Reflections.invokeMethod;
 import static org.omnifaces.utils.stream.Collectors.toMap;
 import static org.omnifaces.utils.stream.Streams.stream;
 
@@ -77,6 +79,9 @@ public final class JPA {
     public static final String QUERY_HINT_CACHE_RETRIEVE_MODE = "jakarta.persistence.cache.retrieveMode"; // USE | BYPASS
     public static final String PROPERTY_VALIDATION_MODE = "jakarta.persistence.validation.mode"; // AUTO | CALLBACK | NONE
 
+    // Private constants ------------------------------------------------------------------------------------------------------------------
+
+    private static final Optional<Class<Object>> HIBERNATE_6_6_0_JPA_EXPRESSION = findClass("org.hibernate.query.criteria.JpaExpression");
 
     // Constructors -----------------------------------------------------------------------------------------------------------------------
 
@@ -353,8 +358,16 @@ public static Expression<String> concat(CriteriaBuilder builder, Object... expre
      */
     @SuppressWarnings("unchecked")
     public static Expression<String> castAsString(CriteriaBuilder builder, Expression<?> expression) {
+
+        // NOTE: Improvement for all providers is expected in JPA 3.2 with new Expression#cast() API.
+
         if (Provider.is(HIBERNATE)) {
-            return expression.as(String.class);
+            if (HIBERNATE_6_6_0_JPA_EXPRESSION.isPresent() && HIBERNATE_6_6_0_JPA_EXPRESSION.get().isInstance(expression)) {
+                return invokeMethod(expression, "cast", String.class); // https://hibernate.atlassian.net/browse/HHH-18710
+            }
+            else {
+                return expression.as(String.class);
+            }
         }
 
         // EclipseLink and OpenJPA have a broken Expression#as() implementation, need to delegate to DB specific function.