OAK-11415: TypeEditor: constraint exception for node type violations should contain that node's effective type

oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/nodetype/TypeEditor.java

@@ -458,23 +458,29 @@ private static boolean mixinsChanged(NodeState before, Iterable<String> after) {
     private void checkNodeTypeConstraints(NodeState after) throws CommitFailedException {
         EffectiveType effective = getEffective();
 
+        // check mandatory properties
+
         Set<String> properties = effective.getMandatoryProperties();
         for (PropertyState ps : after.getProperties()) {
             properties.remove(ps.getName());
             checkPropertyTypeConstraints(ps);
         }
         // verify the presence of all mandatory items
         if (!properties.isEmpty()) {
-            constraintViolation(21, "Mandatory property '" + properties.iterator().next() + "' not found in a new node");
+            constraintViolation(21, "Mandatory properties '" + properties + "' not found in a new node of type '" + effective + "'");
         }
 
+        // check mandatory child nodes
+
         List<String> names = ListUtils.toList(after.getChildNodeNames());
         for (String child : effective.getMandatoryChildNodes()) {
             if (!names.remove(child)) {
-                constraintViolation(25, "Mandatory child node '" + child + "' not found in a new node");
+                constraintViolation(25, "Mandatory child node '" + child + "' not found in a new node of type '" + effective + "'");
             }
         }
 
+        // of the child node names left after above check, verify that these are allowed by the node type
+
         for (String name : names) {
             if (!NodeStateUtils.isHidden(name)) {
                 NodeState child = after.getChildNode(name);