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Fix usage of whole-row variables in WCO and RLS policy expressions.

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Since WITH CHECK OPTION was introduced, ExecInitModifyTable has
initialized WCO expressions with the wrong plan node as parent -- that is,
it passed its input subplan not the ModifyTable node itself.  Up to now
we thought this was harmless, but bug #16006 from Vinay Banakar shows it's
not: if the input node is a SubqueryScan then ExecInitWholeRowVar can get
confused into doing the wrong thing.  (The fact that ExecInitWholeRowVar
contains such logic is certainly a horrid kluge that doesn't deserve to
live, but figuring out another way to do that is a task for some other day.)

Andres had already noticed the wrong-parent mistake and fixed it in commit
148e632c0, but not being aware of any user-visible consequences, he quite
reasonably didn't back-patch.  This patch is simply a back-patch of
148e632c0, plus addition of a test case based on bug #16006.  I also added
the test case to v12/HEAD, even though the bug is already fixed there.

Back-patch to all supported branches.  9.4 lacks RLS policies so the
new test case doesn't work there, but I'm pretty sure a test could be
devised based on using a whole-row Var in a plain WITH CHECK OPTION
condition.  (I lack the cycles to do so myself, though.)

Andres Freund and Tom Lane

Discussion: https://postgr.es/m/16006-99290d2e4642cbd5@postgresql.org
Discussion: https://postgr.es/m/20181205225213.hiwa3kgoxeybqcqv@alap3.anarazel.de
This commit is contained in:
Tom Lane 2019-09-12 18:29:18 -04:00
parent 1f705e68ee
commit ca08ea52bf
2 changed files with 15 additions and 15 deletions
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2
src/backend/executor/nodeModifyTable.c
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@ -1198,7 +1198,7 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
{ {
WithCheckOption *wco = (WithCheckOption *) lfirst(ll); WithCheckOption *wco = (WithCheckOption *) lfirst(ll);
ExprState *wcoExpr = ExecInitExpr((Expr *) wco->qual, ExprState *wcoExpr = ExecInitExpr((Expr *) wco->qual,
mtstate->mt_plans[i]); &mtstate->ps);
wcoExprs = lappend(wcoExprs, wcoExpr); wcoExprs = lappend(wcoExprs, wcoExpr);
} }

4
src/test/regress/expected/updatable_views.out
View File

@ -1605,7 +1605,7 @@ ERROR: new row violates WITH CHECK OPTION for view "rw_view1"
DETAIL: Failing row contains (15). DETAIL: Failing row contains (15).
EXPLAIN (costs off) INSERT INTO rw_view1 VALUES (5); EXPLAIN (costs off) INSERT INTO rw_view1 VALUES (5);
QUERY PLAN QUERY PLAN
--------------------------------------------------------------- ---------------------------------------------------------
Insert on base_tbl b Insert on base_tbl b
-> Result -> Result
SubPlan 1 SubPlan 1
@ -1617,7 +1617,7 @@ EXPLAIN (costs off) INSERT INTO rw_view1 VALUES (5);
EXPLAIN (costs off) UPDATE rw_view1 SET a = a + 5; EXPLAIN (costs off) UPDATE rw_view1 SET a = a + 5;
QUERY PLAN QUERY PLAN
----------------------------------------------------------------- -----------------------------------------------------------
Update on base_tbl b Update on base_tbl b
-> Hash Semi Join -> Hash Semi Join
Hash Cond: (b.a = r.a) Hash Cond: (b.a = r.a)