Make sure the affinity and datatype of sub-subqueries are initialized

prior to subqueries as the latter relies on the former.

FossilOrigin-Name: 39b4e6ff9316cc78ea88349091e195b8104d1e9e

src/expr.c

@@ -1214,6 +1214,7 @@ static int selectNodeIsConstant(Walker *pWalker, Select *NotUsed){
 }
 static int exprIsConst(Expr *p, int initFlag){
   Walker w;
+  memset(&w, 0, sizeof(w));
   w.u.i = initFlag;
   w.xExprCallback = exprNodeIsConstant;
   w.xSelectCallback = selectNodeIsConstant;
@@ -3428,8 +3429,8 @@ void sqlite3ExprCodeConstants(Parse *pParse, Expr *pExpr){
   Walker w;
   if( pParse->cookieGoto ) return;
   if( OptimizationDisabled(pParse->db, SQLITE_FactorOutConst) ) return;
+  memset(&w, 0, sizeof(w));
   w.xExprCallback = evalConstExpr;
-  w.xSelectCallback = 0;
   w.pParse = pParse;
   sqlite3WalkExpr(&w, pExpr);
 }

src/resolve.c

@@ -1283,6 +1283,7 @@ int sqlite3ResolveExprNames(
 #endif
   savedHasAgg = pNC->ncFlags & NC_HasAgg;
   pNC->ncFlags &= ~NC_HasAgg;
+  memset(&w, 0, sizeof(w));
   w.xExprCallback = resolveExprStep;
   w.xSelectCallback = resolveSelectStep;
   w.pParse = pNC->pParse;
@@ -1323,6 +1324,7 @@ void sqlite3ResolveSelectNames(
   Walker w;
 
   assert( p!=0 );
+  memset(&w, 0, sizeof(w));
   w.xExprCallback = resolveExprStep;
   w.xSelectCallback = resolveSelectStep;
   w.pParse = pParse;

src/select.c

@@ -3576,6 +3576,7 @@ static int exprWalkNoop(Walker *NotUsed, Expr *NotUsed2){
 */
 static void sqlite3SelectExpand(Parse *pParse, Select *pSelect){
   Walker w;
+  memset(&w, 0, sizeof(w));
   w.xSelectCallback = selectExpander;
   w.xExprCallback = exprWalkNoop;
   w.pParse = pParse;
@@ -3634,9 +3635,11 @@ static int selectAddSubqueryTypeInfo(Walker *pWalker, Select *p){
 static void sqlite3SelectAddTypeInfo(Parse *pParse, Select *pSelect){
 #ifndef SQLITE_OMIT_SUBQUERY
   Walker w;
+  memset(&w, 0, sizeof(w));
   w.xSelectCallback = selectAddSubqueryTypeInfo;
   w.xExprCallback = exprWalkNoop;
   w.pParse = pParse;
+  w.bSelectDepthFirst = 1;
   sqlite3WalkSelect(&w, pSelect);
 #endif
 }

src/sqliteInt.h

@@ -2588,6 +2588,7 @@ struct Walker {
   int (*xSelectCallback)(Walker*,Select*);  /* Callback for SELECTs */
   Parse *pParse;                            /* Parser context.  */
   int walkerDepth;                          /* Number of subqueries */
+  u8 bSelectDepthFirst;                     /* Do subqueries first */
   union {                                   /* Extra data for callback */
     NameContext *pNC;                          /* Naming context */
     int i;                                     /* Integer value */

src/walker.c

@@ -113,7 +113,9 @@ int sqlite3WalkSelectFrom(Walker *pWalker, Select *p){
 /*
 ** Call sqlite3WalkExpr() for every expression in Select statement p.
 ** Invoke sqlite3WalkSelect() for subqueries in the FROM clause and
-** on the compound select chain, p->pPrior.
+** on the compound select chain, p->pPrior.  Invoke the xSelectCallback()
+** either before or after the walk of expressions and FROM clause, depending
+** on whether pWalker->bSelectDepthFirst is false or true, respectively.
 **
 ** Return WRC_Continue under normal conditions.  Return WRC_Abort if
 ** there is an abort request.
@@ -127,14 +129,23 @@ int sqlite3WalkSelect(Walker *pWalker, Select *p){
   rc = WRC_Continue;
   pWalker->walkerDepth++;
   while( p ){
-    rc = pWalker->xSelectCallback(pWalker, p);
-    if( rc ) break;
+    if( !pWalker->bSelectDepthFirst ){
+       rc = pWalker->xSelectCallback(pWalker, p);
+       if( rc ) break;
+    }
     if( sqlite3WalkSelectExpr(pWalker, p)
      || sqlite3WalkSelectFrom(pWalker, p)
     ){
       pWalker->walkerDepth--;
       return WRC_Abort;
     }
+    if( pWalker->bSelectDepthFirst ){
+      rc = pWalker->xSelectCallback(pWalker, p);
+      /* Depth-first search is currently only used for
+      ** selectAddSubqueryTypeInfo() and that routine always returns
+      ** WRC_Continue (0).  So the following branch is never taken. */
+      if( NEVER(rc) ) break;
+    }
     p = p->pPrior;
   }
   pWalker->walkerDepth--;