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Alternative fix to ticket [c8d3b9f0a750a529]: Prior to deleting or modifying

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an Expr not that is referenced by an AggInfo, modify the AggInfo to get its
own copy of the original Expr.

FossilOrigin-Name: 7682d8a768fbccfe0cc956e9f6481637146e1ab9763b248ff11052761ce32e32
This commit is contained in:
drh
2020-06-07 17:33:18 +00:00
parent a0365c487c
commit 896366282d
9 changed files with 276 additions and 23 deletions
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62
src/expr.c
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@@ -5709,6 +5709,66 @@ int sqlite3FunctionUsesThisSrc(Expr *pExpr, SrcList *pSrcList){
return cnt.nThis>0 || cnt.nOther==0;
}
/*
** This is a Walker expression node callback.
**
** For Expr nodes that contain pAggInfo pointers, make sure the AggInfo
** object that is referenced does not refer directly to the Expr. If
** it does, make a copy. This is done because the pExpr argument is
** subject to change.
**
** The copy is stored on pParse->pConstExpr with a register number of 0.
** This will cause the expression to be deleted automatically when the
** Parse object is destroyed, but the zero register number means that it
** will not generate any code in the preamble.
*/
static int agginfoPersistExprCb(Walker *pWalker, Expr *pExpr){
if( !ExprHasProperty(pExpr, EP_TokenOnly|EP_Reduced)
&& pExpr->pAggInfo!=0
){
AggInfo *pAggInfo = pExpr->pAggInfo;
int iAgg = pExpr->iAgg;
Parse *pParse = pWalker->pParse;
sqlite3 *db = pParse->db;
assert( pAggInfo->iAggMagic==AggInfoMagic );
assert( pExpr->op==TK_COLUMN || pExpr->op==TK_AGG_COLUMN
|| pExpr->op==TK_FUNCTION || pExpr->op==TK_AGG_FUNCTION );
if( pExpr->op==TK_COLUMN || pExpr->op==TK_AGG_COLUMN ){
assert( iAgg>=0 && iAgg<pAggInfo->nColumn );
if( pAggInfo->aCol[iAgg].pExpr==pExpr ){
pExpr = sqlite3ExprDup(db, pExpr, 0);
if( pExpr ){
pAggInfo->aCol[iAgg].pExpr = pExpr;
pParse->pConstExpr =
sqlite3ExprListAppend(pParse, pParse->pConstExpr, pExpr);
}
}
}else{
assert( iAgg>=0 && iAgg<pAggInfo->nFunc );
if( pAggInfo->aFunc[iAgg].pExpr==pExpr ){
pExpr = sqlite3ExprDup(db, pExpr, 0);
if( pExpr ){
pAggInfo->aFunc[iAgg].pExpr = pExpr;
pParse->pConstExpr =
sqlite3ExprListAppend(pParse, pParse->pConstExpr, pExpr);
}
}
}
}
return WRC_Continue;
}
/*
** Initialize a Walker object so that will persist AggInfo entries referenced
** by the tree that is walked.
*/
void sqlite3AggInfoPersistWalkerInit(Walker *pWalker, Parse *pParse){
memset(pWalker, 0, sizeof(*pWalker));
pWalker->pParse = pParse;
pWalker->xExprCallback = agginfoPersistExprCb;
pWalker->xSelectCallback = sqlite3SelectWalkNoop;
}
/*
** Add a new element to the pAggInfo->aCol[] array. Return the index of
** the new element. Return a negative number if malloc fails.
@@ -5739,7 +5799,7 @@ static int addAggInfoFunc(sqlite3 *db, AggInfo *pInfo){
&i
);
return i;
}
}
/*
** This is the xExprCallback for a tree walker. It is used to