Обсуждение: BUG #17464: Domain type. If the value field(CREATE DOMAIN) is set to null, errors cannot be intercepted.

The following bug has been logged on the website:

Bug reference:      17464
Logged by:          Domain type. If the value field(CREATE DOMAIN) is set to null, errors cannot
be intercepted.
Email address:      dafoer_x@163.com
PostgreSQL version: 13.2
Operating system:   centos7.6 x86
Description:

Domain type. If the value field(CREATE DOMAIN) is set to null, errors cannot
be intercepted.
Because texteq cannot accept null input parameters,
op->d.domainCheck.checknull is set to the wrong value .

detail:
postgres=# call f3_basic('男');
NOTICE:  a_xb = 男
CALL
postgres=# call  f3_basic('她');
NOTICE:  a_xb = 她
CALL


eg.
drop domain xb;
CREATE DOMAIN xb AS TEXT CHECK
(
   VALUE = '男'
   OR VALUE ='女'
   OR VALUE = null
 );
drop procedure if exists f3_basic(a_xb xb);
CREATE OR REPLACE procedure f3_basic (a_xb xb)  AS
$$
BEGIN
 RAISE NOTICE 'a_xb = %',a_xb;
END;
$$
LANGUAGE PLPGSQL;
-- success
call f3_basic('男');
-- expected error
call  f3_basic('她');
drop procedure if exists f3_basic(a_xb xb);
drop domain xb;

"David G. Johnston" <david.g.johnston@gmail.com> writes:
> "VALUES = null" is simply wrong.  That isn't how one checks for null.  Use
> "IS NULL".  If that restores the correct behavior I'm unsure what we'd be
> willing to do to behave differently in the presence of the improper null
> test form.

There's already transform_null_equals, which does work if you turn it on
while executing this incorrect CREATE DOMAIN command.  But the better
answer is to fix your SQL.

regression=# set transform_null_equals = 1;
SET
regression=# CREATE DOMAIN xb AS TEXT CHECK
regression-# (
regression(#    VALUE = '男'
regression(#    OR VALUE ='女'
regression(#    OR VALUE = null
regression(#  );
CREATE DOMAIN
regression=# \dD+ xb
                                                                       List of domains
 Schema | Name | Type | Collation | Nullable | Default |                               Check
   | Access privileges | Description  

--------+------+------+-----------+----------+---------+--------------------------------------------------------------------+-------------------+-------------
 public | xb   | text |           |          |         | CHECK (VALUE = '男'::text OR VALUE = '女'::text OR VALUE IS
NULL)|                   |  
(1 row)


            regards, tom lane