TASK: document and assert Node.nodeName behavior

related #4311

Neos.ContentRepository.Core/Classes/Projection/ContentGraph/Node.php

@@ -44,7 +44,7 @@
      * @param NodeTypeName $nodeTypeName The node's node type name; always set, even if unknown to the NodeTypeManager
      * @param NodeType|null $nodeType The node's node type, null if unknown to the NodeTypeManager - @deprecated Don't rely on this too much, as the capabilities of the NodeType here will probably change a lot; Ask the {@see NodeTypeManager} instead
      * @param PropertyCollection $properties All properties of this node. References are NOT part of this API; To access references, {@see ContentSubgraphInterface::findReferences()} can be used; To read the serialized properties, call properties->serialized().
-     * @param NodeName|null $nodeName The optional name of this node {@see ContentSubgraphInterface::findChildNodeConnectedThroughEdgeName()}
+     * @param NodeName|null $nodeName The nodeÄs name. The name is guaranteed to be for tethered nodes. For the regular classification, it can be set optionally. One can traverse the edges via {@see ContentSubgraphInterface::findChildNodeConnectedThroughEdgeName()}.
      * @param Timestamps $timestamps Creation and modification timestamps of this node
      */
     private function __construct(
@@ -58,6 +58,9 @@ private function __construct(
         public ?NodeName $nodeName,
         public Timestamps $timestamps,
     ) {
+        if ($this->classification->isTethered() && $this->nodeName === null) {
+            throw new \InvalidArgumentException('The NodeName must be set if the Node is tethered.', 1695118377);
+        }
     }
 
     /**