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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 22:45:35 +00:00
parent 45c84659ee
commit 14686de2b5

View File

@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.186.4.5 2007/02/02 00:03:44 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.186.4.6 2007/03/06 22:45:35 tgl Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@@ -1580,6 +1580,7 @@ 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;
}
}
@@ -2260,8 +2261,9 @@ 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(result_type, get_typtype(result_type),
querytree_list, NULL);
if (check_sql_fn_retval(result_type, get_typtype(result_type),
querytree_list, NULL))
goto fail; /* reject whole-tuple-result cases */
/*
* Additional validity checks on the expression. It mustn't return a
@@ -2346,6 +2348,21 @@ 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.