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When generating code for a subquery, make a copy of the Select object and

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generate the code out of the copy, in case the code generator makes
modifications to expression and the Select object needs to be reused.

FossilOrigin-Name: 4edddcc0bc8d71e9b8abac67bc3766f1d9143dddd1f59264859ce65e5aa9b8c6
This commit is contained in:
drh
2020-01-01 21:14:30 +00:00
parent 4ea562ee70
commit fc705da15d
4 changed files with 34 additions and 12 deletions
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15
src/expr.c
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@@ -2933,6 +2933,8 @@ int sqlite3CodeSubselect(Parse *pParse, Expr *pExpr){
SelectDest dest; /* How to deal with SELECT result */
int nReg; /* Registers to allocate */
Expr *pLimit; /* New limit expression */
Select *pCopy; /* Copy of pSel */
int rc; /* return value from subroutine call */
Vdbe *v = pParse->pVdbe;
assert( v!=0 );
@@ -3016,9 +3018,16 @@ int sqlite3CodeSubselect(Parse *pParse, Expr *pExpr){
pSel->pLimit = sqlite3PExpr(pParse, TK_LIMIT, pLimit, 0);
}
pSel->iLimit = 0;
if( sqlite3Select(pParse, pSel, &dest) ){
return 0;
}
/* pSel might be reused. So generate code using a copy of pSel, so that
** if the code generator modifies the underlying structure of the SELECT
** (for example in whereIndexExprTrans()) the original in pSel will be
** unchanged. */
pCopy = sqlite3SelectDup(pParse->db, pSel, 0);
rc = sqlite3Select(pParse, pCopy, &dest);
sqlite3SelectDelete(pParse->db, pCopy);
if( rc ) return 0;
pExpr->iTable = rReg = dest.iSDParm;
ExprSetVVAProperty(pExpr, EP_NoReduce);
if( addrOnce ){