Fix an assert() in window.c that could fail with some obscure SELECT statements that use window functions.
FossilOrigin-Name: 83dc55679a91bf5d1d13706088ce58eed02b9aad1ad0ae237966e78e0d769663
diff --git a/src/expr.c b/src/expr.c
index 4e8703e..67b5ce7 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -5183,8 +5183,9 @@
}
/*
-** Compare two ExprList objects. Return 0 if they are identical and
-** non-zero if they differ in any way.
+** Compare two ExprList objects. Return 0 if they are identical, 1
+** if they are certainly different, or 2 if it is not possible to
+** determine if they are identical or not.
**
** If any subelement of pB has Expr.iTable==(-1) then it is allowed
** to compare equal to an equivalent element in pA with Expr.iTable==iTab.
@@ -5203,10 +5204,11 @@
if( pA==0 || pB==0 ) return 1;
if( pA->nExpr!=pB->nExpr ) return 1;
for(i=0; i<pA->nExpr; i++){
+ int res;
Expr *pExprA = pA->a[i].pExpr;
Expr *pExprB = pB->a[i].pExpr;
if( pA->a[i].sortFlags!=pB->a[i].sortFlags ) return 1;
- if( sqlite3ExprCompare(0, pExprA, pExprB, iTab) ) return 1;
+ if( (res = sqlite3ExprCompare(0, pExprA, pExprB, iTab)) ) return res;
}
return 0;
}
diff --git a/src/window.c b/src/window.c
index 5fb78ce..a72ec0d 100644
--- a/src/window.c
+++ b/src/window.c
@@ -1279,10 +1279,12 @@
}
/*
-** Return 0 if the two window objects are identical, or non-zero otherwise.
-** Identical window objects can be processed in a single scan.
+** Return 0 if the two window objects are identical, 1 if they are
+** different, or 2 if it cannot be determined if the objects are identical
+** or not. Identical window objects can be processed in a single scan.
*/
int sqlite3WindowCompare(Parse *pParse, Window *p1, Window *p2, int bFilter){
+ int res;
if( NEVER(p1==0) || NEVER(p2==0) ) return 1;
if( p1->eFrmType!=p2->eFrmType ) return 1;
if( p1->eStart!=p2->eStart ) return 1;
@@ -1290,10 +1292,16 @@
if( p1->eExclude!=p2->eExclude ) return 1;
if( sqlite3ExprCompare(pParse, p1->pStart, p2->pStart, -1) ) return 1;
if( sqlite3ExprCompare(pParse, p1->pEnd, p2->pEnd, -1) ) return 1;
- if( sqlite3ExprListCompare(p1->pPartition, p2->pPartition, -1) ) return 1;
- if( sqlite3ExprListCompare(p1->pOrderBy, p2->pOrderBy, -1) ) return 1;
+ if( (res = sqlite3ExprListCompare(p1->pPartition, p2->pPartition, -1)) ){
+ return res;
+ }
+ if( (res = sqlite3ExprListCompare(p1->pOrderBy, p2->pOrderBy, -1)) ){
+ return res;
+ }
if( bFilter ){
- if( sqlite3ExprCompare(pParse, p1->pFilter, p2->pFilter, -1) ) return 1;
+ if( (res = sqlite3ExprCompare(pParse, p1->pFilter, p2->pFilter, -1)) ){
+ return res;
+ }
}
return 0;
}
@@ -1580,7 +1588,7 @@
/* All OVER clauses in the same window function aggregate step must
** be the same. */
- assert( pWin==pMWin || sqlite3WindowCompare(pParse,pWin,pMWin,0)==0 );
+ assert( pWin==pMWin || sqlite3WindowCompare(pParse,pWin,pMWin,0)!=1 );
for(i=0; i<nArg; i++){
if( i!=1 || pFunc->zName!=nth_valueName ){