BUG #18793: PLpgSQL Function Returning Type of Table is not match for varchar(n) data type via Return Query

The following bug has been logged on the website:

Bug reference: 18793
Logged by: Ugur YILMAZ
Email address: ugurlu2001(at)hotmail(dot)com
PostgreSQL version: 17.2
Operating system: Windows 11 Pro
Description:

I have a set of "Functions" that I created dynamically with PLPgSQL and are
connected to each other in a chain.

The first function dynamically creates the second function. The second
function returns a set of values with a dynamic "Return Query" statement and
a reference to "Returns Table (field1 type1, field2 type2 .... )".

Basically, the result set seems to return exactly the desired result. The
exception is the varchar(n) fixed-length data type. Although the result set
is expected to be varchar(n) -a fixed-length value is expected-, a result of
type character varying (length indeterminate) is obtained.

You can see the dynamically created function example that I use below. In
addition to the sample function, I am also sharing the "Basic SQL" sentence
that returns "character varying (length indeterminate)" data. It also
returns the correct result.

I have been trying to solve this seemingly simple problem for a few days.
However, I have a special restriction on the Varchar(254) limit in my
development environment.

Correctly working SQL script:

-- kodx > returning character varying :: length indeterminate
SELECT idx,kodx, guidx
,round(has_toplam::numeric,2) as has
,round(gumus_toplam::numeric,2) as gumus
,round(usd_toplam::numeric,2) as usd
,round(eur_toplam::numeric,2) as eur
,round(trl_toplam::numeric,2) as trl
,round(gbp_toplam::numeric,2) as gbp
,round(chf_toplam::numeric,2) as chf
,round(platin_toplam::numeric,2) as platin
,round(alloy_toplam::numeric,2) as alloy
FROM crosstab('
SELECT idx, kodx, guidx, bt_kod, toplam_miktar FROM
(
SELECT cma.company_master_id as idx, bt.kod AS bt_kod, bt.sys_default,
SUM(cma.miktar) as toplam_miktar, cm.kod as kodx, cma.company_master_guid as
guidx FROM company_master_amounts AS cma
LEFT OUTER JOIN balance_types as bt ON cma.balance_types_guid = bt.guid

LEFT OUTER JOIN company_master as cm ON cm.id = cma.company_master_id
WHERE company_master_id = 3
GROUP BY cma.company_master_id, bt.kod, bt.sys_default, cm.kod,
cma.company_master_guid
) ORDER BY idx, sys_default DESC, bt_kod
'::TEXT,
' SELECT kod as kodx FROM balance_types ORDER BY sys_default DESC, kod, id
'::TEXT)
crosstab(idx integer, kodx character varying(200), guidx uuid
,has_toplam numeric(22,6),gumus_toplam numeric(22,6)
,usd_toplam numeric(22,6),eur_toplam numeric(22,6)
,trl_toplam numeric(22,6),gbp_toplam numeric(22,6)
,chf_toplam numeric(22,6),platin_toplam numeric(22,6)
,alloy_toplam numeric(22,6))
GROUP BY
has_toplam,gumus_toplam,usd_toplam,eur_toplam,trl_toplam,gbp_toplam,chf_toplam,platin_toplam,alloy_toplam,kodx,guidx,idx

ORDER BY kodx;

A function that returns a result of indefinite length in the form of
"character varying" instead of "Code ::varchar(200)". A "Returns Query"
function that creates a dynamic SQL script and returns a value in the "Table
Type" (second level - needed by the end user):

-- kodx ( field name kod on "return table" ) > returning character varying
(200)
/*
FUNCTION: public.get_balance_pivot_1c(integer)
DROP FUNCTION IF EXISTS public.get_balance_pivot_1c(integer);
Select * from get_balance_pivot_1c(3) ;
*/
CREATE OR REPLACE FUNCTION public.get_balance_pivot_1c(
pintcompany_id integer)
RETURNS TABLE(id integer, kod varchar(200), guid uuid, has numeric,
gumus numeric, usd numeric, eur numeric, trl numeric, gbp numeric, chf
numeric, platin numeric, alloy numeric)
LANGUAGE 'plpgsql'
COST 100
STABLE PARALLEL SAFE
ROWS 1000

AS $BODY$
BEGIN
RETURN QUERY

SELECT idx,kodx::varchar(200), guidx
,round(has_toplam::numeric,2) as has
,round(gumus_toplam::numeric,2) as gumus
,round(usd_toplam::numeric,2) as usd
,round(eur_toplam::numeric,2) as eur
,round(trl_toplam::numeric,2) as trl
,round(gbp_toplam::numeric,2) as gbp
,round(chf_toplam::numeric,2) as chf
,round(platin_toplam::numeric,2) as platin
,round(alloy_toplam::numeric,2) as alloy
FROM crosstab('
SELECT idx, kodx, guidx, bt_kod, toplam_miktar FROM
(
SELECT cma.company_master_id as idx, bt.kod AS bt_kod, bt.sys_default,
SUM(cma.miktar) as toplam_miktar, cm.kod as kodx, cma.company_master_guid as
guidx FROM company_master_amounts AS cma
LEFT OUTER JOIN balance_types as bt ON cma.balance_types_guid = bt.guid

LEFT OUTER JOIN company_master as cm ON cm.id = cma.company_master_id
WHERE company_master_id = 3
GROUP BY cma.company_master_id, bt.kod, bt.sys_default, cm.kod,
cma.company_master_guid
) ORDER BY idx, sys_default DESC, bt_kod
'::TEXT,
' SELECT kod as kodx FROM balance_types ORDER BY sys_default DESC, kod, id
'::TEXT) crosstab(idx integer, kodx character varying(200), guidx uuid,
has_toplam numeric(22,6),gumus_toplam numeric(22,6),usd_toplam
numeric(22,6),eur_toplam numeric(22,6),trl_toplam numeric(22,6),gbp_toplam
numeric(22,6),chf_toplam numeric(22,6),platin_toplam
numeric(22,6),alloy_toplam numeric(22,6))
GROUP BY
has_toplam,gumus_toplam,usd_toplam,eur_toplam,trl_toplam,gbp_toplam,chf_toplam,platin_toplam,alloy_toplam,kodx,guidx,idx

ORDER BY kodx;
/* WHERE company_master_id = ' || pintcompany_id || ' */
/* WHERE company_master_id = ' || '3' || ' */

END ;

$BODY$;

ALTER FUNCTION public.get_balance_pivot_1c(integer)
OWNER TO postgres;

As far as I have determined, the Postgresql database engine somehow returns
the varchar(n) - Fixed Length - data type as a "character varying" -
indefinite length data type.

I hope this situation, which I observed as a problem, will be fixed as soon
as possible.

Best wishes...