Merge pull request ethereum#640 from ngtuna/nil-node-2

fix nil node on RBT

tomox/orderbook.go

@@ -134,7 +134,7 @@ func (orderBook *OrderBook) Restore(dryrun bool) error {
 		log.Error("can't save asks changes to DB", "err", err)
 		return err
 	}
-	log.Debug("restored orderbook asks", "asks.Item", orderBook.Bids.Item)
+	log.Debug("restored orderbook asks", "asks.Item", orderBook.Asks.Item)
 
 	if err := orderBook.Bids.Restore(dryrun); err != nil {
 		log.Error("can't restore orderbook bids", "err", err)

tomox/redblacktree.go

@@ -186,6 +186,21 @@ func (tree *Tree) Remove(key []byte, dryrun bool) {
 			child = right
 		}
 		if child == nil {
+			parent := node.Parent(tree, dryrun)
+			if parent != nil {
+				if !tree.IsEmptyKey(parent.LeftKey()) && bytes.Equal(parent.LeftKey(), node.Key) {
+					parent.Item.Keys.Left = EmptyKey()
+					log.Debug("Set parent.LeftKey() to nil", "parent.Key", parent.Item.Keys)
+					tree.Save(parent, dryrun)
+				} else if !tree.IsEmptyKey(parent.RightKey()) && bytes.Equal(parent.RightKey(), node.Key) {
+					parent.Item.Keys.Right = EmptyKey()
+					log.Debug("Set parent.RightKey() to nil", "parent.Key", parent.Item.Keys)
+					tree.Save(parent, dryrun)
+				} else {
+					log.Error("Parent doesn't have node as child", "node.Key", hex.EncodeToString(node.Key))
+					return
+				}
+			}
 			tree.deleteNode(node, dryrun)
 			log.Debug("Removed node with child = nil", "node", hex.EncodeToString(node.Key), "all keys", tree.KeysinString(true))
 		} else {