Re: First draft of PG 19 release notes - Mailing list pgsql-hackers

On Wed, Apr 15, 2026 at 10:19 AM Bruce Momjian <bruce@momjian.us> wrote:
> I have completed the first draft of the PG 19 release notes:
>
>         https://www.postgresql.org/docs/devel/release-19.html

I just committed 8d829f5a0 to fix JSON_ARRAY(subquery) to return an
empty JSON array instead of NULL over an empty result set, per the
SQL/JSON standard.  Since this is a user-visible behavior change, we
need to add an item to the v19 migration section to call it out.

Suggested entry:

 - Make JSON_ARRAY(query_expression) return an empty JSON array when
   the subquery returns no rows (Richard Guo)

   Previously, an empty result set produced NULL.  This corrects the
   behavior to match the SQL/JSON standard.  Application code that
   relied on the previous NULL behavior may need to be updated.

- Richard