From 89dc302694ea1308cd974cccfdefcbf4c7ee2e45 Mon Sep 17 00:00:00 2001
From: Daniel <845765@qq.com>
Date: Fri, 26 Dec 2025 21:58:49 +0800
Subject: [PATCH] :bug: The `updateBlock` API encountered a null pointer error
 https://github.com/siyuan-note/siyuan/issues/16705

Signed-off-by: Daniel <845765@qq.com>
---
 kernel/api/block_op.go | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/kernel/api/block_op.go b/kernel/api/block_op.go
index 31b5567a8..1d58fb9af 100644
--- a/kernel/api/block_op.go
+++ b/kernel/api/block_op.go
@@ -25,6 +25,7 @@ import (
 	"github.com/88250/lute/ast"
 	"github.com/88250/lute/parse"
 	"github.com/gin-gonic/gin"
+	"github.com/siyuan-note/logging"
 	"github.com/siyuan-note/siyuan/kernel/filesys"
 	"github.com/siyuan-note/siyuan/kernel/model"
 	"github.com/siyuan-note/siyuan/kernel/treenode"
@@ -701,7 +702,13 @@ func updateBlock(c *gin.Context) {
 			tree.Root.FirstChild.Unlink()                          // 删除列表
 			tree.Root.FirstChild.Unlink()                          // 继续删除列表 IAL
 		}
-		tree.Root.FirstChild.SetIALAttr("id", id)
+
+		if nil != tree.Root.FirstChild {
+			tree.Root.FirstChild.SetIALAttr("id", id)
+		} else {
+			logging.LogWarnf("tree root has no child node when updating block [id=%s]", id)
+			return
+		}
 
 		data = luteEngine.Tree2BlockDOM(tree, luteEngine.RenderOptions, luteEngine.ParseOptions)
 		transactions = []*model.Transaction{