Fix jsonForceRCStr() to also add the NULL terminator.

FossilOrigin-Name: 134b01f37f8f741d7f7b7eda81384695d1cbe4c39751d87f08832d5c9afdcef2

1 files changed, 16 insertions, 12 deletions

diff --git a/src/json.c b/src/json.c
index a4a3e65c9..3ad5af659 100644
--- a/src/json.c
+++ b/src/json.c
@@ -248,16 +248,6 @@ static int jsonGrow(JsonString *p, u32 N){
   return SQLITE_OK;
 }
 
-/* Try to force the string to be an RCStr string, rather than a
-** static string.  Return true on success.  The only reason this
-** might fail is due to an OOM fault.
-*/
-static int jsonForceRCStr(JsonString *p){
-  if( p->bStatic==0 ) return 1;
-  jsonGrow(p, p->nAlloc+1);
-  return p->bStatic==0;
-}
-
 /* Append N bytes from zIn onto the end of the JsonString string.
 */
 static SQLITE_NOINLINE void jsonAppendExpand(
@@ -315,6 +305,22 @@ static void jsonAppendChar(JsonString *p, char c){
   }
 }
 
+/* Try to force the string to be a zero-terminated RCStr string.
+**
+** Return true on success.  Return false if an OOM prevents this
+** from happening.
+*/
+static int jsonForceRCStr(JsonString *p){
+  jsonAppendChar(p, 0);
+  if( p->bErr ) return 0;
+  p->nUsed--;
+  if( p->bStatic==0 ) return 1;
+  p->nAlloc = 0;
+  jsonGrow(p, p->nUsed);
+  return p->bStatic==0;
+}
+
+
 /* Append a comma separator to the output buffer, if the previous
 ** character is not '[' or '{'.
 */
@@ -798,8 +804,6 @@ static void jsonReturnJson(
     jsonInit(&s, pCtx);
     jsonRenderNode(pParse, pNode, &s);
     if( bGenerateAlt && pParse->zAlt==0 && jsonForceRCStr(&s) ){
-      jsonAppendChar(&s, 0);
-      s.nUsed--;
       pParse->zAlt = sqlite3RCStrRef(s.zBuf);
       pParse->nAlt = s.nUsed;
     }