Fix oversight in original coding of inline_function(): since

check_sql_fn_retval allows binary-compatibility cases, the expression
extracted from an inline-able SQL function might have a type that is only
binary-compatible with the declared function result type.  To avoid possibly
changing the semantics of the expression, we should insert a RelabelType node
in such cases.  This has only been shown to have bad consequences in recent
8.1 and up releases, but I suspect there may be failure cases in the older
branches too, so patch it all the way back.  Per bug #3116 from Greg Mullane.

Along the way, fix an omission in eval_const_expressions_mutator: it failed
to copy the relabelformat field when processing a RelabelType.  No known
observable failures from this, but it definitely isn't intended behavior.
This commit is contained in:
Tom Lane 2007-03-06 22:45:23 +00:00
parent 3530283dae
commit cafbf1e1cc

View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.223.2.1 2007/02/02 00:03:17 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.223.2.2 2007/03/06 22:45:23 tgl Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@ -1842,6 +1842,7 @@ eval_const_expressions_mutator(Node *node,
newrelabel->arg = (Expr *) arg;
newrelabel->resulttype = relabel->resulttype;
newrelabel->resulttypmod = relabel->resulttypmod;
newrelabel->relabelformat = relabel->relabelformat;
return (Node *) newrelabel;
}
}
@ -2795,7 +2796,8 @@ inline_function(Oid funcid, Oid result_type, List *args,
* no rewriting was needed; that's probably not important, but let's be
* careful.
*/
(void) check_sql_fn_retval(funcid, result_type, querytree_list, NULL);
if (check_sql_fn_retval(funcid, result_type, querytree_list, NULL))
goto fail; /* reject whole-tuple-result cases */
/*
* Additional validity checks on the expression. It mustn't return a set,
@ -2880,6 +2882,21 @@ inline_function(Oid funcid, Oid result_type, List *args,
MemoryContextDelete(mycxt);
/*
* Since check_sql_fn_retval allows binary-compatibility cases, the
* expression we now have might return some type that's only binary
* compatible with the original expression result type. To avoid
* confusing matters, insert a RelabelType in such cases.
*/
if (exprType(newexpr) != funcform->prorettype)
{
Assert(IsBinaryCoercible(exprType(newexpr), funcform->prorettype));
newexpr = (Node *) makeRelabelType((Expr *) newexpr,
funcform->prorettype,
-1,
COERCE_IMPLICIT_CAST);
}
/*
* Recursively try to simplify the modified expression. Here we must add
* the current function to the context list of active functions.