From d35821abe7cb287cfe3bc8d083e5471db1708475 Mon Sep 17 00:00:00 2001
From: Ti Chi Robot <ti-community-prow-bot@tidb.io>
Date: Thu, 14 Apr 2022 21:00:36 +0800
Subject: [PATCH] fix null case for GetJsonLength (#3734) (#3737)

close pingcap/tiflash#2705
---
 dbms/src/Storages/Transaction/JSONCodec.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/dbms/src/Storages/Transaction/JSONCodec.cpp b/dbms/src/Storages/Transaction/JSONCodec.cpp
index 5c7755f2b5c..24656657065 100644
--- a/dbms/src/Storages/Transaction/JSONCodec.cpp
+++ b/dbms/src/Storages/Transaction/JSONCodec.cpp
@@ -61,7 +61,6 @@
  */
 namespace DB
 {
-
 namespace ErrorCodes
 {
 extern const int LOGICAL_ERROR;
@@ -277,6 +276,10 @@ String DecodeJsonAsBinary(size_t & cursor, const String & raw_value) { return De
 
 UInt64 GetJsonLength(std::string_view raw_value)
 {
+    if (raw_value.empty())
+    {
+        return 0;
+    }
     switch (raw_value[0]) // JSON Root element type
     {
         case TYPE_CODE_OBJECT: