radixdb: attach fresh prefix node to current

Previously, nodes with newly discovered prefixes were attached to the
parent of the current node, which is incorrect. Instead, these nodes
should be attached to the current node. This commit also fixes an
incorrect suffix extraction from newNode.

radixdb.go

@@ -123,10 +123,9 @@ func (rdb *RadixDB) Insert(key []byte, value any) error {
 		// at the deepest level of the tree for the given key.
 		key = key[len(prefix):]
 		nextNode := current.findCompatibleChild(key)
+		newNode.key = newNode.key[len(prefix):]
 
 		if nextNode == nil {
-			newNode.key = key
-
 			if current == rdb.root {
 				// A root node with nil key means that it's an intermediate node
 				// with existing edges to child nodes.
@@ -142,7 +141,7 @@ func (rdb *RadixDB) Insert(key []byte, value any) error {
 				rdb.numNodes++
 				return nil
 			} else {
-				parent.children = append(parent.children, newNode)
+				current.children = append(current.children, newNode)
 			}
 
 			rdb.numNodes++
@@ -152,7 +151,6 @@ func (rdb *RadixDB) Insert(key []byte, value any) error {
 		// Reaching this point means that a compatible child was found.
 		// Update relevant iterators and continue traversing the tree until
 		// we reach a leaf node or no further nodes are available.
-		newNode.key = newNode.key[len(prefix):]
 		parent = current
 		current = nextNode
 	}