Re: BUG #19046: Incorrect result when using json_array() with column reference in subquery combined with RIGHT JOIN

Richard Guo <guofenglinux@gmail.com>

From: Richard Guo <guofenglinux@gmail.com>

To: Tender Wang <tndrwang@gmail.com>

Cc: runyuan@berkeley.edu, pgsql-bugs@lists.postgresql.org, Tom Lane <tgl@sss.pgh.pa.us>

Date: 2025-09-11T03:10:15Z

Lists: pgsql-bugs

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Treat JsonConstructorExpr as non-strict
- 62397bb1893b 16.11 landed
- d719e2ecb188 17.7 landed
- d29a3f4b46a0 18.0 landed
- b63a82245215 19 (unreleased) landed
Avoid inserting PlaceHolderVars in cases where pre-v16 PG did not.
- cb8e50a4a09f 18.0 cited

On Thu, Sep 11, 2025 at 10:40 AM Tender Wang <tndrwang@gmail.com> wrote:
> Richard Guo <guofenglinux@gmail.com> 于2025年9月10日周三 21:29写道：
>> I'm wondering if this is the only case we've overlooked.  How about
>> other Json-related expressions?

> Yeah, I have the same question. I tried my fix on json_object/json_arrayagg/json_objectagg.
> These returned the same results.

json_object is also represented as a JsonConstructorExpr.

json_arrayagg and json_objectagg are aggregates, so the subquery won't
be pulled up in the first place.

I tested JsonExpr, which is the representation of json_value,
json_query and json_exists.  It seems that they could not produce
non-NULL output with a NULL input.  So we are good on that front.

- Richard