Index: src/utf.c
==================================================================
--- src/utf.c
+++ src/utf.c
@@ -314,11 +314,11 @@
   *z = 0;
   assert( (pMem->n+(desiredEnc==SQLITE_UTF8?1:2))<=len );
 
   c = pMem->flags;
   sqlite3VdbeMemRelease(pMem);
-  pMem->flags = MEM_Str|MEM_Term|(c&MEM_AffMask);
+  pMem->flags = MEM_Str|MEM_Term|(c&(MEM_AffMask|MEM_Subtype));
   pMem->enc = desiredEnc;
   pMem->z = (char*)zOut;
   pMem->zMalloc = pMem->z;
   pMem->szMalloc = sqlite3DbMallocSize(pMem->db, pMem->z);
 

Index: src/vdbe.c
==================================================================
--- src/vdbe.c
+++ src/vdbe.c
@@ -469,11 +469,11 @@
   }else{
     char zBuf[200];
     sqlite3VdbeMemPrettyPrint(p, zBuf);
     printf(" %s", zBuf);
   }
-  if( p->eSubtype ) printf(" subtype=0x%02x", p->eSubtype);
+  if( p->flags & MEM_Subtype ) printf(" subtype=0x%02x", p->eSubtype);
 }
 static void registerTrace(int iReg, Mem *p){
   printf("REG[%d] = ", iReg);
   memTracePrint(p);
   printf("\n");

Index: src/vdbeInt.h
==================================================================
--- src/vdbeInt.h
+++ src/vdbeInt.h
@@ -236,11 +236,11 @@
 #define MEM_AffMask   0x001f   /* Mask of affinity bits */
 #define MEM_RowSet    0x0020   /* Value is a RowSet object */
 #define MEM_Frame     0x0040   /* Value is a VdbeFrame object */
 #define MEM_Undefined 0x0080   /* Value is undefined */
 #define MEM_Cleared   0x0100   /* NULL set by OP_Null, not from data */
-#define MEM_TypeMask  0x01ff   /* Mask of type bits */
+#define MEM_TypeMask  0x81ff   /* Mask of type bits */
 
 
 /* Whenever Mem contains a valid string or blob representation, one of
 ** the following flags must be set to determine the memory management
 ** policy for Mem.z.  The MEM_Term flag tells us whether or not the
@@ -250,14 +250,21 @@
 #define MEM_Dyn       0x0400   /* Need to call Mem.xDel() on Mem.z */
 #define MEM_Static    0x0800   /* Mem.z points to a static string */
 #define MEM_Ephem     0x1000   /* Mem.z points to an ephemeral string */
 #define MEM_Agg       0x2000   /* Mem.z points to an agg function context */
 #define MEM_Zero      0x4000   /* Mem.i contains count of 0s appended to blob */
+#define MEM_Subtype   0x8000   /* Mem.eSubtype is valid */
 #ifdef SQLITE_OMIT_INCRBLOB
   #undef MEM_Zero
   #define MEM_Zero 0x0000
 #endif
+
+/* Return TRUE if Mem X contains dynamically allocated content - anything
+** that needs to be deallocated to avoid a leak.
+*/
+#define VdbeMemDynamic(X)  \
+  (((X)->flags&(MEM_Agg|MEM_Dyn|MEM_RowSet|MEM_Frame))!=0)
 
 /*
 ** Clear any existing type flags from a Mem and replace them with f
 */
 #define MemSetTypeFlag(p, f) \
@@ -470,12 +477,10 @@
 int sqlite3VdbeMemRealify(Mem*);
 int sqlite3VdbeMemNumerify(Mem*);
 void sqlite3VdbeMemCast(Mem*,u8,u8);
 int sqlite3VdbeMemFromBtree(BtCursor*,u32,u32,int,Mem*);
 void sqlite3VdbeMemRelease(Mem *p);
-#define VdbeMemDynamic(X)  \
-  (((X)->flags&(MEM_Agg|MEM_Dyn|MEM_RowSet|MEM_Frame))!=0)
 int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
 const char *sqlite3OpcodeName(int);
 int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
 int sqlite3VdbeMemClearAndResize(Mem *pMem, int n);
 int sqlite3VdbeCloseStatement(Vdbe *, int);

Index: src/vdbeapi.c
==================================================================
--- src/vdbeapi.c
+++ src/vdbeapi.c
@@ -186,11 +186,12 @@
 }
 sqlite_int64 sqlite3_value_int64(sqlite3_value *pVal){
   return sqlite3VdbeIntValue((Mem*)pVal);
 }
 unsigned int sqlite3_value_subtype(sqlite3_value *pVal){
-  return ((Mem*)pVal)->eSubtype;
+  Mem *pMem = (Mem*)pVal;
+  return ((pMem->flags & MEM_Subtype) ? pMem->eSubtype : 0);
 }
 const unsigned char *sqlite3_value_text(sqlite3_value *pVal){
   return (const unsigned char *)sqlite3ValueText(pVal, SQLITE_UTF8);
 }
 #ifndef SQLITE_OMIT_UTF16
@@ -367,12 +368,14 @@
 void sqlite3_result_null(sqlite3_context *pCtx){
   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
   sqlite3VdbeMemSetNull(pCtx->pOut);
 }
 void sqlite3_result_subtype(sqlite3_context *pCtx, unsigned int eSubtype){
-  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
-  pCtx->pOut->eSubtype = eSubtype & 0xff;
+  Mem *pOut = pCtx->pOut;
+  assert( sqlite3_mutex_held(pOut->db->mutex) );
+  pOut->eSubtype = eSubtype & 0xff;
+  pOut->flags |= MEM_Subtype;
 }
 void sqlite3_result_text(
   sqlite3_context *pCtx, 
   const char *z, 
   int n,

Index: test/json103.test
==================================================================
--- test/json103.test
+++ test/json103.test
@@ -58,8 +58,21 @@
 do_execsql_test json103-220 {
   SELECT b, json_group_object(c,a) FROM t1
    WHERE rowid<7 GROUP BY b ORDER BY b;
 } {0 {{"n3":3,"n6":6}} 1 {{"n1":1,"n4":4}} 2 {{"n2":2,"n5":5}}}
 
-
+# ticket https://www.sqlite.org/src/info/f45ac567eaa9f93c 2016-01-30
+# Invalid JSON generated by json_group_array() 
+#
+# The underlying problem is a failure to reset Mem.eSubtype
+#
+do_execsql_test json103-300 {
+  DROP TABLE IF EXISTS t1;
+  CREATE TABLE t1(x);
+  INSERT INTO t1 VALUES(1),('abc');
+  SELECT
+     json_group_array(x),
+     json_group_array(json_object('x',x))
+    FROM t1;
+} {{[1,"abc"]} {[{"x":1},{"x":"abc"}]}}
 
 finish_test