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Overview
Comment:Avoid a dangling pointer comparison when renaming a table that has a trigger that itself contains a window function with an (illegal) column reference in a FOLLOWING expression.
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SHA3-256: d45bee36f2c1091a2d32c16ca8921bf4e7c9e40c46d0a36fbcb179ecfafcfbf0
User & Date: dan 2019-01-16 12:05:22
Context
2019-01-16
14:58
Fix a problem with renaming a column that is used as part of an ORDER BY on a compound SELECT within a database view or trigger. check-in: b4b57413 user: dan tags: trunk
12:05
Avoid a dangling pointer comparison when renaming a table that has a trigger that itself contains a window function with an (illegal) column reference in a FOLLOWING expression. check-in: d45bee36 user: dan tags: trunk
11:38
Fix a memory leak that could occur in fts3 when handling a corrupt database. check-in: 65cebb06 user: dan tags: trunk
Changes
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Changes to src/window.c.

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** value should be a non-negative integer.  If the value is not a
** constant, change it to NULL.  The fact that it is then a non-negative
** integer will be caught later.  But it is important not to leave
** variable values in the expression tree.
*/
static Expr *sqlite3WindowOffsetExpr(Parse *pParse, Expr *pExpr){
  if( 0==sqlite3ExprIsConstant(pExpr) ){

    sqlite3ExprDelete(pParse->db, pExpr);
    pExpr = sqlite3ExprAlloc(pParse->db, TK_NULL, 0, 0);
  }
  return pExpr;
}

/*







>







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** value should be a non-negative integer.  If the value is not a
** constant, change it to NULL.  The fact that it is then a non-negative
** integer will be caught later.  But it is important not to leave
** variable values in the expression tree.
*/
static Expr *sqlite3WindowOffsetExpr(Parse *pParse, Expr *pExpr){
  if( 0==sqlite3ExprIsConstant(pExpr) ){
    if( IN_RENAME_OBJECT ) sqlite3RenameExprUnmap(pParse, pExpr);
    sqlite3ExprDelete(pParse->db, pExpr);
    pExpr = sqlite3ExprAlloc(pParse->db, TK_NULL, 0, 0);
  }
  return pExpr;
}

/*

Changes to test/altertab2.test.

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  ALTER TABLE t1x RENAME d TO ddd;
  SELECT sql FROM sqlite_master WHERE type = 'trigger';
} {
{CREATE TRIGGER r1 AFTER INSERT ON "t1x" WHEN new.aaa NOT NULL BEGIN
    UPDATE "t1x" SET (c,ddd)=(aaa,b);
  END}
}
























































finish_test








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  ALTER TABLE t1x RENAME d TO ddd;
  SELECT sql FROM sqlite_master WHERE type = 'trigger';
} {
{CREATE TRIGGER r1 AFTER INSERT ON "t1x" WHEN new.aaa NOT NULL BEGIN
    UPDATE "t1x" SET (c,ddd)=(aaa,b);
  END}
}

#-------------------------------------------------------------------------
do_execsql_test 5.0 {
  CREATE TABLE t2(a);
  CREATE TRIGGER r2 AFTER INSERT ON t2 WHEN new.a NOT NULL BEGIN
    SELECT a, rank() OVER w1 FROM t2
      WINDOW w1 AS (
        PARTITION BY b ORDER BY d ROWS BETWEEN 2 PRECEDING AND a FOLLOWING
      ),
      w2 AS (
        PARTITION BY b 
        ORDER BY d ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
      );
  END;
} {}

do_catchsql_test 5.0.1 {
  INSERT INTO t2 VALUES(1);
} {1 {no such column: b}}

do_execsql_test 5.1 {
  ALTER TABLE t2 RENAME TO t2x;
  SELECT sql FROM sqlite_master WHERE name = 'r2';
} {
  {CREATE TRIGGER r2 AFTER INSERT ON "t2x" WHEN new.a NOT NULL BEGIN
    SELECT a, rank() OVER w1 FROM "t2x"
      WINDOW w1 AS (
        PARTITION BY b ORDER BY d ROWS BETWEEN 2 PRECEDING AND a FOLLOWING
      ),
      w2 AS (
        PARTITION BY b 
        ORDER BY d ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
      );
  END}
}

do_execsql_test 5.2 {
  ALTER TABLE t2x RENAME a TO aaaa;
  SELECT sql FROM sqlite_master WHERE name = 'r2';
} {
  {CREATE TRIGGER r2 AFTER INSERT ON "t2x" WHEN new.aaaa NOT NULL BEGIN
    SELECT aaaa, rank() OVER w1 FROM "t2x"
      WINDOW w1 AS (
        PARTITION BY b ORDER BY d ROWS BETWEEN 2 PRECEDING AND a FOLLOWING
      ),
      w2 AS (
        PARTITION BY b 
        ORDER BY d ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
      );
  END}
}

do_catchsql_test 5.3 {
  INSERT INTO t2x VALUES(1);
} {1 {no such column: b}}

finish_test