Polymorphic functions' weird behavior
Hello
We've come across the following issue with Polymorphic functions:
CREATE OR REPLACE FUNCTION "array_to_set" (vaarray anyarray) RETURNS
SETOF anyelement AS
$body$
BEGIN
FOR I IN COALESCE(ARRAY_LOWER(VAARRAY, 1), 1) ..
COALESCE(ARRAY_UPPER(VAARRAY, 1), 0) LOOP
RETURN NEXT VAARRAY[I];
END LOOP;
END
$body$
LANGUAGE 'plpgsql' SECURITY INVOKER;
select * from array_to_set(array[1,2,3]);
array_to_set
--------------
1
2
3
(3 rows)
Now we change SECURITY INVOKER clause to SECURITY DEFINER and voila:
select * from array_to_set(array[1,2,3]);
ERROR: could not determine actual argument type for polymorphic
function "array_to_set"
Though explainable this is absolutely strange since logically security
rules and polymorphism are irrelevant.
regards, Viatcheslav
Viatcheslav Kalinin <vka@ipcb.net> writes:
Now we change SECURITY INVOKER clause to SECURITY DEFINER and voila:
select * from array_to_set(array[1,2,3]);
ERROR: could not determine actual argument type for polymorphic
function "array_to_set"
Wow, apparently you're the first person ever to try that, because it's
never worked in any release since polymorphism was introduced :-(.
Thanks for the report!
The fix is pretty easy if you need it now:
Index: fmgr.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/fmgr/fmgr.c,v
retrieving revision 1.102
diff -c -r1.102 fmgr.c
*** fmgr.c 4 Oct 2006 00:30:01 -0000 1.102
--- fmgr.c 31 Jul 2007 15:39:29 -0000
***************
*** 793,798 ****
--- 793,799 ---- fmgr_info_cxt_security(fcinfo->flinfo->fn_oid, &fcache->flinfo,
fcinfo->flinfo->fn_mcxt, true);
+ fcache->flinfo.fn_expr = fcinfo->flinfo->fn_expr;
tuple = SearchSysCache(PROCOID,
ObjectIdGetDatum(fcinfo->flinfo->fn_oid),
regards, tom lane
Tom Lane wrote:
The fix is pretty easy if you need it now
Thanks for the update, Tom.
Another little issue with that function. I cannot make it
accept NULL as an argument. It won't normally accept NULL
reporting an appropriate error that it cannot determine
argument type, nor will it accept it if I make the
function STRICT, nor can I handle it inside the function
since it isn't actually called. Thus I always get the
error which is not desirable behavior. Any way around it?
regards, Viatcheslav
Import Notes
Resolved by subject fallback
"Vyacheslav Kalinin" <vka@ipcb.net> writes:
Another little issue with that function. I cannot make it
accept NULL as an argument.
You'd have to cast the NULL to some specific array type.
regards, tom lane
Tom Lane wrote:
You'd have to cast the NULL to some specific array type.
regards, tom lane
Unfortunately I can't do that (well, in fact it would be pretty
inconvenient) because the function is called from other plpgsql function
and I cannot be sure if it will be called with NULL or not. Anyway I
seem to resolved the problem by writing another doing-nothing-at-all
function with the same name and "unknown' argument type.
regards, Viatcheslav