Merge pull request #5749 from taosdata/hotfix/TD-3720

[TD-3720]final fields may be freed while fetching rows

src/client/inc/tsclient.h

@@ -125,7 +125,6 @@ typedef struct SInternalField {
 
 typedef struct SFieldInfo {
   int16_t      numOfOutput;   // number of column in result
-  TAOS_FIELD*  final;
   SArray      *internalField; // SArray<SInternalField>
 } SFieldInfo;
 
@@ -316,6 +315,7 @@ typedef struct {
   char **        buffer;  // Buffer used to put multibytes encoded using unicode (wchar_t)
   SColumnIndex*  pColumnIndex;
 
+  TAOS_FIELD*           final;
   SArithmeticSupport   *pArithSup;   // support the arithmetic expression calculation on agg functions
   struct SLocalMerger  *pLocalMerger;
 } SSqlRes;

src/client/src/tscSql.c

@@ -405,6 +405,7 @@ int taos_affected_rows(TAOS_RES *tres) {
 
 TAOS_FIELD *taos_fetch_fields(TAOS_RES *res) {
   SSqlObj *pSql = (SSqlObj *)res;
+  SSqlRes *pRes = &pSql->res;
   if (pSql == NULL || pSql->signature != pSql) return 0;
 
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(&pSql->cmd, 0);
@@ -419,7 +420,7 @@ TAOS_FIELD *taos_fetch_fields(TAOS_RES *res) {
 
   SFieldInfo *pFieldInfo = &pQueryInfo->fieldsInfo;
 
-  if (pFieldInfo->final == NULL) {
+  if (pRes->final == NULL) {
     TAOS_FIELD* f = calloc(pFieldInfo->numOfOutput, sizeof(TAOS_FIELD));
 
     int32_t j = 0;
@@ -439,10 +440,10 @@ TAOS_FIELD *taos_fetch_fields(TAOS_RES *res) {
       }
     }
 
-    pFieldInfo->final = f;
+    pRes->final = f;
   }
 
-  return pFieldInfo->final;
+  return pRes->final;
 }
 
 static bool needToFetchNewBlock(SSqlObj* pSql) {

src/client/src/tscUtil.c

@@ -429,6 +429,8 @@ static void tscDestroyResPointerInfo(SSqlRes* pRes) {
     tfree(pRes->pArithSup->data);
     tfree(pRes->pArithSup);
   }
+
+  tfree(pRes->final);
   
   pRes->data = NULL;  // pRes->data points to the buffer of pRsp, no need to free
 }
@@ -1153,7 +1155,6 @@ void tscFieldInfoClear(SFieldInfo* pFieldInfo) {
   }
   
   taosArrayDestroy(pFieldInfo->internalField);
-  tfree(pFieldInfo->final);
 
   memset(pFieldInfo, 0, sizeof(SFieldInfo));
 }