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Overview
Comment:Prevent SQLite from assuming that if ((? IS NOT NULL) IS NOT NULL) is true, ? may not be NULL. Fix for [c31034044bb72c89].
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SHA3-256: 7833feecfe745e237f239ee4c38a9e4bf7ad66a32919150208da87c00a826473
User & Date: dan 2019-10-10 17:09:44
Original Comment: Prevent SQLite from assuming that if ((? IS NOT NULL) IS NOT NULL) is true, ? may not be NULL. Fix for [d51a8696].
Context
2019-10-10
23:58
Fix harmless compiler warning seen with MSVC. check-in: 73a82114 user: mistachkin tags: trunk
17:09
Prevent SQLite from assuming that if ((? IS NOT NULL) IS NOT NULL) is true, ? may not be NULL. Fix for [c31034044bb72c89]. check-in: 7833feec user: dan tags: trunk
16:41
Fix a problem in the fts3 integrity-check routine causing it to report as corrupt tables that contain values with embedded 0x00 bytes. Ticket [278ac142625e3dcd] check-in: 629e20c9 user: dan tags: trunk
Changes
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Changes to src/expr.c.

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      if( pWalker->u.iCur==pExpr->iTable ){
        pWalker->eCode = 1;
        return WRC_Abort;
      }
      return WRC_Prune;

    case TK_AND:
      if( sqlite3ExprImpliesNonNullRow(pExpr->pLeft, pWalker->u.iCur)
       && sqlite3ExprImpliesNonNullRow(pExpr->pRight, pWalker->u.iCur)
      ){
        pWalker->eCode = 1;

      }
      return WRC_Prune;

    case TK_BETWEEN:
      sqlite3WalkExpr(pWalker, pExpr->pLeft);
      return WRC_Prune;

................................................................................
** clause requires that some column of the right table of the LEFT JOIN
** be non-NULL, then the LEFT JOIN can be safely converted into an
** ordinary join.
*/
int sqlite3ExprImpliesNonNullRow(Expr *p, int iTab){
  Walker w;
  p = sqlite3ExprSkipCollateAndLikely(p);
  while( p ){
    if( p->op==TK_NOTNULL ){
      p = p->pLeft;
    }else if( p->op==TK_AND ){
      if( sqlite3ExprImpliesNonNullRow(p->pLeft, iTab) ) return 1;
      p = p->pRight;
    }else{
      break;
    }
  }
  w.xExprCallback = impliesNotNullRow;
  w.xSelectCallback = 0;
  w.xSelectCallback2 = 0;
  w.eCode = 0;
  w.u.iCur = iTab;
  sqlite3WalkExpr(&w, p);







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      if( pWalker->u.iCur==pExpr->iTable ){
        pWalker->eCode = 1;
        return WRC_Abort;
      }
      return WRC_Prune;

    case TK_AND:
      assert( pWalker->eCode==0 );
      sqlite3WalkExpr(pWalker, pExpr->pLeft);
      if( pWalker->eCode ){
        pWalker->eCode = 0;
        sqlite3WalkExpr(pWalker, pExpr->pRight);
      }
      return WRC_Prune;

    case TK_BETWEEN:
      sqlite3WalkExpr(pWalker, pExpr->pLeft);
      return WRC_Prune;

................................................................................
** clause requires that some column of the right table of the LEFT JOIN
** be non-NULL, then the LEFT JOIN can be safely converted into an
** ordinary join.
*/
int sqlite3ExprImpliesNonNullRow(Expr *p, int iTab){
  Walker w;
  p = sqlite3ExprSkipCollateAndLikely(p);

  if( p && p->op==TK_NOTNULL ){
    p = p->pLeft;






  }
  w.xExprCallback = impliesNotNullRow;
  w.xSelectCallback = 0;
  w.xSelectCallback2 = 0;
  w.eCode = 0;
  w.u.iCur = iTab;
  sqlite3WalkExpr(&w, p);

Changes to test/join.test.

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do_execsql_test join-18.3 {
  SELECT * FROM t1 LEFT JOIN t0 WHERE NOT(a IS FALSE);
} {1 {}}

do_execsql_test join-18.4 {
  SELECT NOT(v0.a IS FALSE) FROM v0
} {1}































finish_test









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do_execsql_test join-18.3 {
  SELECT * FROM t1 LEFT JOIN t0 WHERE NOT(a IS FALSE);
} {1 {}}

do_execsql_test join-18.4 {
  SELECT NOT(v0.a IS FALSE) FROM v0
} {1}

#-------------------------------------------------------------------------
reset_db
do_execsql_test join-19.0 {
  CREATE TABLE t1(a);
  CREATE TABLE t2(b);
  INSERT INTO t1(a) VALUES(0);
  CREATE VIEW v0(c) AS SELECT t2.b FROM t1 LEFT JOIN t2;
}

do_execsql_test join-19.1 {
  SELECT * FROM v0 WHERE v0.c NOTNULL NOTNULL; 
} {{}}

do_execsql_test join-19.2 {
  SELECT * FROM t1 LEFT JOIN t2
} {0 {}}

do_execsql_test join-19.3 {
  SELECT * FROM t1 LEFT JOIN t2 WHERE (b IS NOT NULL) IS NOT NULL; 
} {0 {}}

do_execsql_test join-19.4 {
  SELECT (b IS NOT NULL) IS NOT NULL FROM t1 LEFT JOIN t2
} {1}

do_execsql_test join-19.5 {
  SELECT * FROM t1 LEFT JOIN t2 WHERE 
    (b IS NOT NULL AND b IS NOT NULL) IS NOT NULL; 
} {0 {}}

finish_test