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Commit18e8f06

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Arrange to give error when a SetOp member statement refers to a variable
of the containing query (which really can only happen in a rule context).Per example from Brandon Craig Rhodes. Also, make the error messagemore specific for the similar case with sub-select in FROM. The revisedcoding should be easier to adapt to SQL99's LATERAL(), when we get aroundto supporting that.
1 parent53c15ce commit18e8f06

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3 files changed

+49
-37
lines changed

3 files changed

+49
-37
lines changed

‎src/backend/parser/analyze.c‎

Lines changed: 15 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -6,7 +6,7 @@
66
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
77
* Portions Copyright (c) 1994, Regents of the University of California
88
*
9-
*$Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.262 2003/02/11 04:13:06 tgl Exp $
9+
*$Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.263 2003/02/13 20:45:21 tgl Exp $
1010
*
1111
*-------------------------------------------------------------------------
1212
*/
@@ -23,6 +23,7 @@
2323
#include"commands/prepare.h"
2424
#include"nodes/makefuncs.h"
2525
#include"optimizer/clauses.h"
26+
#include"optimizer/var.h"
2627
#include"parser/analyze.h"
2728
#include"parser/gramparse.h"
2829
#include"parser/parsetree.h"
@@ -1982,6 +1983,19 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt)
19821983

19831984
Assert(length(selectList)==1);
19841985
selectQuery= (Query*)lfirst(selectList);
1986+
Assert(IsA(selectQuery,Query));
1987+
1988+
/*
1989+
* Check for bogus references to Vars on the current query level
1990+
* (but upper-level references are okay).
1991+
* Normally this can't happen because the namespace will be empty,
1992+
* but it could happen if we are inside a rule.
1993+
*/
1994+
if (pstate->p_namespace)
1995+
{
1996+
if (contain_vars_of_level((Node*)selectQuery,1))
1997+
elog(ERROR,"UNION/INTERSECT/EXCEPT member statement may not refer to other relations of same query level");
1998+
}
19851999

19862000
/*
19872001
* Make the leaf query be a subquery in the top-level rangetable.

‎src/backend/parser/parse_clause.c‎

Lines changed: 34 additions & 35 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/parser/parse_clause.c,v 1.108 2003/02/1305:53:46 momjian Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/parser/parse_clause.c,v 1.109 2003/02/1320:45:21 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -383,7 +383,6 @@ transformTableEntry(ParseState *pstate, RangeVar *r)
383383
staticRangeTblRef*
384384
transformRangeSubselect(ParseState*pstate,RangeSubselect*r)
385385
{
386-
List*save_namespace;
387386
List*parsetrees;
388387
Query*query;
389388
RangeTblEntry*rte;
@@ -398,21 +397,10 @@ transformRangeSubselect(ParseState *pstate, RangeSubselect *r)
398397
elog(ERROR,"sub-select in FROM must have an alias");
399398

400399
/*
401-
* Analyze and transform the subquery.This is a bit tricky because
402-
* we don't want the subquery to be able to see any FROM items already
403-
* created in the current query (per SQL92, the scope of a FROM item
404-
* does not include other FROM items).But it does need to be able to
405-
* see any further-up parent states, so we can't just pass a null
406-
* parent pstate link.So, temporarily make the current query level
407-
* have an empty namespace.
400+
* Analyze and transform the subquery.
408401
*/
409-
save_namespace=pstate->p_namespace;
410-
pstate->p_namespace=NIL;
411-
412402
parsetrees=parse_analyze(r->subquery,pstate);
413403

414-
pstate->p_namespace=save_namespace;
415-
416404
/*
417405
* Check that we got something reasonable.Some of these conditions
418406
* are probably impossible given restrictions of the grammar, but
@@ -429,6 +417,25 @@ transformRangeSubselect(ParseState *pstate, RangeSubselect *r)
429417
if (query->resultRelation!=0||query->into!=NULL||query->isPortal)
430418
elog(ERROR,"Subselect in FROM may not have SELECT INTO");
431419

420+
/*
421+
* The subquery cannot make use of any variables from FROM items created
422+
* earlier in the current query. Per SQL92, the scope of a FROM item
423+
* does not include other FROM items. Formerly we hacked the namespace
424+
* so that the other variables weren't even visible, but it seems more
425+
* useful to leave them visible and give a specific error message.
426+
*
427+
* XXX this will need further work to support SQL99's LATERAL() feature,
428+
* wherein such references would indeed be legal.
429+
*
430+
* We can skip groveling through the subquery if there's not anything
431+
* visible in the current query. Also note that outer references are OK.
432+
*/
433+
if (pstate->p_namespace)
434+
{
435+
if (contain_vars_of_level((Node*)query,1))
436+
elog(ERROR,"Subselect in FROM may not refer to other relations of same query level");
437+
}
438+
432439
/*
433440
* OK, build an RTE for the subquery.
434441
*/
@@ -455,7 +462,6 @@ transformRangeFunction(ParseState *pstate, RangeFunction *r)
455462
{
456463
Node*funcexpr;
457464
char*funcname;
458-
List*save_namespace;
459465
RangeTblEntry*rte;
460466
RangeTblRef*rtr;
461467

@@ -464,31 +470,24 @@ transformRangeFunction(ParseState *pstate, RangeFunction *r)
464470
funcname=strVal(llast(((FuncCall*)r->funccallnode)->funcname));
465471

466472
/*
467-
* Transform the raw FuncCall node. This is a bit tricky because we
468-
* don't want the function expression to be able to see any FROM items
469-
* already created in the current query (compare to
470-
* transformRangeSubselect). But it does need to be able to see any
471-
* further-up parent states. So, temporarily make the current query
472-
* level have an empty namespace. NOTE: this code is OK only because
473-
* the expression can't legally alter the namespace by causing
474-
* implicit relation refs to be added.
473+
* Transform the raw FuncCall node.
475474
*/
476-
save_namespace=pstate->p_namespace;
477-
pstate->p_namespace=NIL;
478-
479475
funcexpr=transformExpr(pstate,r->funccallnode);
480476

481-
pstate->p_namespace=save_namespace;
482-
483477
/*
484-
* We still need to check that the function parameters don't refer to
485-
* any other rels.That could happen despite our hack on the
486-
* namespace if fully-qualified names are used. So, check there are
487-
* no local Var references in the transformed expression. (Outer
488-
* references are OK, and are ignored here.)
478+
* The function parameters cannot make use of any variables from other
479+
* FROM items. (Compare to transformRangeSubselect(); the coding is
480+
* different though because we didn't parse as a sub-select with its own
481+
* level of namespace.)
482+
*
483+
* XXX this will need further work to support SQL99's LATERAL() feature,
484+
* wherein such references would indeed be legal.
489485
*/
490-
if (!bms_is_empty(pull_varnos(funcexpr)))
491-
elog(ERROR,"FROM function expression may not refer to other relations of same query level");
486+
if (pstate->p_namespace)
487+
{
488+
if (contain_vars_of_level(funcexpr,0))
489+
elog(ERROR,"FROM function expression may not refer to other relations of same query level");
490+
}
492491

493492
/*
494493
* Disallow aggregate functions in the expression.(No reason to

‎src/test/regress/expected/rangefuncs.out‎

Lines changed: 0 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -18,7 +18,6 @@ INSERT INTO foo2 VALUES(1, 111);
1818
CREATE FUNCTION foot(int) returns setof foo2 as 'SELECT * FROM foo2 WHERE fooid = $1;' LANGUAGE SQL;
1919
-- supposed to fail with ERROR
2020
select * from foo2, foot(foo2.fooid) z where foo2.f2 = z.f2;
21-
NOTICE: Adding missing FROM-clause entry for table "foo2"
2221
ERROR: FROM function expression may not refer to other relations of same query level
2322
-- function in subselect
2423
select * from foo2 where f2 in (select f2 from foot(foo2.fooid) z where z.fooid = foo2.fooid) ORDER BY 1,2;

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