Re: BUG #19382: Server crash at __nss_database_lookup

> On 3 Apr 2026, at 04:14, surya poondla <suryapoondla4(at)gmail(dot)com> wrote:
>
> <0004-Fix-bug-19382-server-crash-when-ALTER-TYPE-is-used-m.patch>

Hi Surya,

Thanks for the updated patch. I noticed it checks er_tupdesc_id of the
outermost record variable, but does not recurse into nested composite types.
The server still crashes when only an inner type is altered:

CREATE TYPE inner_t AS (x INT, y INT);
CREATE TYPE outer_t AS (a INT, b inner_t);

CREATE OR REPLACE FUNCTION test_nested() RETURNS record LANGUAGE plpgsql AS $$
DECLARE r1 outer_t; r2 outer_t;
BEGIN
r1 := ROW(1, ROW(10, power(2,30)::int4)::inner_t)::outer_t;
ALTER TYPE inner_t ALTER ATTRIBUTE y TYPE TEXT;
r2 := r1;
RETURN r2;
END; $$;

SELECT test_nested(); -- server crash

The same gap exists on the cursor side independently of your patch, and I
have a fix for that part that walks the type tree recursively. IMO the
PL/pgSQL assignment path will need a similar recursive check.

I'm definitely not a big fan of checking types on every FETCH, but I see no
other ways around.

Best regards, Andrey Borodin.