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Date: Fri, 31 Jul 2026 05:41:01 +0000
Message-Id: <DKCIKZ4EKEYG.23Y7N7F8CLCKO@partin.io>
Cc: <pgsql-bugs@lists.postgresql.org>
Subject: Re: BUG #19589: JSON_QUERY rejects domain-over-bytea input when
 using FORMAT JSON ENCODING UTF8.
To: <dllggyx@outlook.com>
From: "Tristan Partin" <tristan@partin.io>
References: <19589-edd0b3b861601fef@postgresql.org>
In-Reply-To: <19589-edd0b3b861601fef@postgresql.org>
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 <https://www.postgresql.org/message-id/DKCIKZ4EKEYG.23Y7N7F8CLCKO%40partin.io>
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On Thu Jul 30, 2026 at 1:40 PM CDT, PG Bug reporting form wrote:
> The following bug has been logged on the website:
>
> Bug reference:      19589
> Logged by:          Yuxiao Guo
> Email address:      dllggyx@outlook.com
> PostgreSQL version: 18.4
> Operating system:   Ubuntu 20.04 x86-64, docker image postgres:18.4
> Description:       =20
>
> Query A and Query B are equivalent, but while JSON_QUERY(... FORMAT JSON
> ENCODING UTF8 ...) accepts a direct bytea input, it incorrectly rejects a
> domain-over-bytea input with the error JSON ENCODING clause is only allow=
ed
> for bytea input type.
>
> PoC:
>
> ```sql
> CREATE DOMAIN d_json_bytea AS bytea;
>
> -- Query A
> SELECT JSON_QUERY(convert_to(txt, 'utf8') FORMAT JSON ENCODING UTF8, '$')=
 AS
> j
> FROM (VALUES ('[1,2]')) AS src(txt);
>
> -- Query B
> SELECT JSON_QUERY(b FORMAT JSON ENCODING UTF8, '$') AS j
> FROM (
>   SELECT convert_to(txt, 'utf8')::d_json_bytea AS b
>   FROM (
>     SELECT txt
>     FROM (
>       SELECT '[1,2]'::text AS txt
>       UNION ALL
>       SELECT '[9,9]'::text WHERE false
>     ) AS u
>     WHERE txt LIKE '[%'
>   ) AS filtered
> ) AS typed;
>
> ```
>
> Result of Query A:
>    j
> --------
>  [1, 2]
> (1 row)
>
> Result of Query B:
> ERROR:  JSON ENCODING clause is only allowed for bytea input type
> LINE 1: SELECT JSON_QUERY(b FORMAT JSON ENCODING UTF8, '$') AS j

Thanks for the report. I am currently taking a look at this. I have=20
reproduced the issue and am working on a fix.

--=20
Tristan Partin
PostgreSQL Contributors Team
AWS (https://aws.amazon.com)