Fix the expression comparison logic to take the COLLATE operator into account.

Ticket [360c6073e197]

FossilOrigin-Name: 44bb1bfe5dedd8054ddd933941ee4112ed8d3b68

1 files changed, 27 insertions, 23 deletions

diff --git a/src/expr.c b/src/expr.c
index 6ba373875..34655f97a 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -3415,57 +3415,61 @@ void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
 }
 
 /*
-** Do a deep comparison of two expression trees.  Return TRUE (non-zero)
-** if they are identical and return FALSE if they differ in any way.
+** Do a deep comparison of two expression trees.  Return 0 if the two
+** expressions are completely identical.  Return 1 if they differ only
+** by a COLLATE operator at the top level.  Return 2 if there are differences
+** other than the top-level COLLATE operator.
 **
-** Sometimes this routine will return FALSE even if the two expressions
+** Sometimes this routine will return 2 even if the two expressions
 ** really are equivalent.  If we cannot prove that the expressions are
-** identical, we return FALSE just to be safe.  So if this routine
-** returns false, then you do not really know for certain if the two
-** expressions are the same.  But if you get a TRUE return, then you
+** identical, we return 2 just to be safe.  So if this routine
+** returns 2, then you do not really know for certain if the two
+** expressions are the same.  But if you get a 0 or 1 return, then you
 ** can be sure the expressions are the same.  In the places where
-** this routine is used, it does not hurt to get an extra FALSE - that
+** this routine is used, it does not hurt to get an extra 2 - that
 ** just might result in some slightly slower code.  But returning
-** an incorrect TRUE could lead to a malfunction.
+** an incorrect 0 or 1 could lead to a malfunction.
 */
 int sqlite3ExprCompare(Expr *pA, Expr *pB){
   int i;
   if( pA==0||pB==0 ){
-    return pB==pA;
+    return pB==pA ? 0 : 2;
   }
   assert( !ExprHasAnyProperty(pA, EP_TokenOnly|EP_Reduced) );
   assert( !ExprHasAnyProperty(pB, EP_TokenOnly|EP_Reduced) );
   if( ExprHasProperty(pA, EP_xIsSelect) || ExprHasProperty(pB, EP_xIsSelect) ){
-    return 0;
+    return 2;
   }
-  if( (pA->flags & EP_Distinct)!=(pB->flags & EP_Distinct) ) return 0;
-  if( pA->op!=pB->op ) return 0;
-  if( !sqlite3ExprCompare(pA->pLeft, pB->pLeft) ) return 0;
-  if( !sqlite3ExprCompare(pA->pRight, pB->pRight) ) return 0;
+  if( (pA->flags & EP_Distinct)!=(pB->flags & EP_Distinct) ) return 2;
+  if( pA->op!=pB->op ) return 2;
+  if( sqlite3ExprCompare(pA->pLeft, pB->pLeft) ) return 2;
+  if( sqlite3ExprCompare(pA->pRight, pB->pRight) ) return 2;
 
   if( pA->x.pList && pB->x.pList ){
-    if( pA->x.pList->nExpr!=pB->x.pList->nExpr ) return 0;
+    if( pA->x.pList->nExpr!=pB->x.pList->nExpr ) return 2;
     for(i=0; i<pA->x.pList->nExpr; i++){
       Expr *pExprA = pA->x.pList->a[i].pExpr;
       Expr *pExprB = pB->x.pList->a[i].pExpr;
-      if( !sqlite3ExprCompare(pExprA, pExprB) ) return 0;
+      if( sqlite3ExprCompare(pExprA, pExprB) ) return 2;
     }
   }else if( pA->x.pList || pB->x.pList ){
-    return 0;
+    return 2;
   }
 
-  if( pA->iTable!=pB->iTable || pA->iColumn!=pB->iColumn ) return 0;
+  if( pA->iTable!=pB->iTable || pA->iColumn!=pB->iColumn ) return 2;
   if( ExprHasProperty(pA, EP_IntValue) ){
     if( !ExprHasProperty(pB, EP_IntValue) || pA->u.iValue!=pB->u.iValue ){
-      return 0;
+      return 2;
     }
   }else if( pA->op!=TK_COLUMN && pA->u.zToken ){
-    if( ExprHasProperty(pB, EP_IntValue) || NEVER(pB->u.zToken==0) ) return 0;
+    if( ExprHasProperty(pB, EP_IntValue) || NEVER(pB->u.zToken==0) ) return 2;
     if( sqlite3StrICmp(pA->u.zToken,pB->u.zToken)!=0 ){
-      return 0;
+      return 2;
     }
   }
-  return 1;
+  if( (pA->flags & EP_ExpCollate)!=(pB->flags & EP_ExpCollate) ) return 1;
+  if( (pA->flags & EP_ExpCollate)!=0 && pA->pColl!=pB->pColl ) return 2;
+  return 0;
 }
 
 
@@ -3596,7 +3600,7 @@ static int analyzeAggregate(Walker *pWalker, Expr *pExpr){
         */
         struct AggInfo_func *pItem = pAggInfo->aFunc;
         for(i=0; i<pAggInfo->nFunc; i++, pItem++){
-          if( sqlite3ExprCompare(pItem->pExpr, pExpr) ){
+          if( sqlite3ExprCompare(pItem->pExpr, pExpr)==0 ){
             break;
           }
         }