From d02a125f34ea35f469b5f4e20e89fc8dc519d699 Mon Sep 17 00:00:00 2001
From: kailixu <klxu@taosdata.com>
Date: Fri, 15 Mar 2024 16:29:10 +0800
Subject: [PATCH] fix: memory leak when alter json tag to NULL

---
 include/common/tmsg.h                  | 1 +
 source/libs/parser/src/parInsertSql.c  | 4 +++-
 source/libs/parser/src/parTranslater.c | 4 ++++
 tests/script/tsim/tag/add.sim          | 1 -
 4 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/include/common/tmsg.h b/include/common/tmsg.h
index 06381a433f..03954e789e 100644
--- a/include/common/tmsg.h
+++ b/include/common/tmsg.h
@@ -2820,6 +2820,7 @@ typedef struct {
   char*    tagName;
   int8_t   isNull;
   int8_t   tagType;
+  int8_t   nullToken;
   uint32_t nTagVal;
   uint8_t* pTagVal;
   SArray*  pTagArray;
diff --git a/source/libs/parser/src/parInsertSql.c b/source/libs/parser/src/parInsertSql.c
index 9efe25b563..5eb0b67884 100644
--- a/source/libs/parser/src/parInsertSql.c
+++ b/source/libs/parser/src/parInsertSql.c
@@ -922,7 +922,8 @@ static int32_t parseTagsClauseImpl(SInsertParseContext* pCxt, SVnodeModifyOpStmt
 
   if (!(pTagVals = taosArrayInit(pCxt->tags.numOfBound, sizeof(STagVal))) ||
       !(pTagName = taosArrayInit(pCxt->tags.numOfBound, TSDB_COL_NAME_LEN))) {
-    return TSDB_CODE_OUT_OF_MEMORY;
+    code = TSDB_CODE_OUT_OF_MEMORY;
+    goto _exit;
   }
 
   for (int i = 0; TSDB_CODE_SUCCESS == code && i < pCxt->tags.numOfBound; ++i) {
@@ -967,6 +968,7 @@ static int32_t parseTagsClauseImpl(SInsertParseContext* pCxt, SVnodeModifyOpStmt
     pTag = NULL;
   }
 
+_exit:
   for (int32_t i = 0; i < TARRAY_SIZE(pTagVals); ++i) {
     STagVal* p = (STagVal*)TARRAY_GET_ELEM(pTagVals, i);
     if (IS_VAR_DATA_TYPE(p->type)) {
diff --git a/source/libs/parser/src/parTranslater.c b/source/libs/parser/src/parTranslater.c
index b29cd85294..1290a640cb 100644
--- a/source/libs/parser/src/parTranslater.c
+++ b/source/libs/parser/src/parTranslater.c
@@ -10442,6 +10442,9 @@ static int32_t buildUpdateTagValReq(STranslateContext* pCxt, SAlterTableStmt* pS
   if (TSDB_CODE_SUCCESS == code) {
     code = parseTagValue(&pCxt->msgBuf, &tagStr, pTableMeta->tableInfo.precision, pSchema, &token, NULL,
                          pReq->pTagArray, &pTag);
+    if (pSchema->type == TSDB_DATA_TYPE_JSON && token.type == TK_NULL && code == TSDB_CODE_SUCCESS) {
+      pReq->nullToken = true;
+    }
   }
   if (TSDB_CODE_SUCCESS == code && tagStr) {
     NEXT_VALID_TOKEN(tagStr, token);
@@ -10703,6 +10706,7 @@ static void destoryAlterTbReq(SVAlterTbReq* pReq) {
     }
   }
   taosArrayDestroy(pReq->pTagArray);
+  if(pReq->nullToken) tTagFree((STag*)pReq->pTagVal);
 }
 
 static int32_t rewriteAlterTableImpl(STranslateContext* pCxt, SAlterTableStmt* pStmt, STableMeta* pTableMeta,
diff --git a/tests/script/tsim/tag/add.sim b/tests/script/tsim/tag/add.sim
index 34a757a5ed..0e0755111d 100644
--- a/tests/script/tsim/tag/add.sim
+++ b/tests/script/tsim/tag/add.sim
@@ -395,7 +395,6 @@ sql alter table $tb set tag tgcol6='1'
 sql reset query cache
 
 sql select * from $mt where tgcol5 = '5'
-print $mt
 print select * from $mt where tgcol5 = 5
 print $data01 $data02 $data03 $data04
 if $rows != 1 then