From 99c82666cb1021d99e15d78d450e841e1361c87b Mon Sep 17 00:00:00 2001
From: Manav Aggarwal <manavaggarwal1234@gmail.com>
Date: Fri, 28 Oct 2022 12:37:33 +0200
Subject: [PATCH] Fix GetSiblingNode

---
 deepsubtree.go | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/deepsubtree.go b/deepsubtree.go
index 3f296e21f..6f93a52cb 100644
--- a/deepsubtree.go
+++ b/deepsubtree.go
@@ -62,7 +62,7 @@ func (tree *ImmutableTree) GetSiblingNode(key []byte) (*Node, error) {
 
 func (tree *ImmutableTree) recursiveGetSiblingNode(node *Node, key []byte) (*Node, error) {
 	if node == nil || node.isLeaf() {
-		return nil, fmt.Errorf("no sibling node found for key: %s", key)
+		return nil, nil
 	}
 	leftNode, err := node.getLeftNode(tree)
 	if err != nil {
@@ -72,14 +72,19 @@ func (tree *ImmutableTree) recursiveGetSiblingNode(node *Node, key []byte) (*Nod
 	if err != nil {
 		return nil, err
 	}
-	if leftNode != nil && bytes.Equal(leftNode.key, key) {
+	if leftNode != nil && leftNode.isLeaf() && bytes.Equal(leftNode.key, key) {
 		return rightNode, nil
 	}
-	if rightNode != nil && bytes.Equal(rightNode.key, key) {
+	if rightNode != nil && rightNode.isLeaf() && bytes.Equal(rightNode.key, key) {
 		return leftNode, nil
 	}
-	if bytes.Compare(node.key, key) < 0 {
-		return tree.recursiveGetSiblingNode(leftNode, key)
+
+	siblingNode, err := tree.recursiveGetSiblingNode(leftNode, key)
+	if err != nil {
+		return nil, err
+	}
+	if siblingNode != nil {
+		return siblingNode, nil
 	}
 	return tree.recursiveGetSiblingNode(rightNode, key)
 }