On Wed, Sep 10, 2025 at 9:31 PM Tender Wang <tndrwang@gmail.com> wrote: >> PG Bug reporting form <noreply@postgresql.org> 于2025年9月10日周三 18:22写道： >>> SELECT sub.c FROM >>> (SELECT json_array(3, 2, t.c) AS c FROM t) AS sub >>> RIGHT JOIN t ON FALSE;
> diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c > index 6f0b338d2cd..5ef364b7f7c 100644 > --- a/src/backend/optimizer/util/clauses.c > +++ b/src/backend/optimizer/util/clauses.c > @@ -1115,6 +1115,8 @@ contain_nonstrict_functions_walker(Node *node, void *context) > return true; > if (IsA(node, BooleanTest)) > return true; > + if (IsA(node, JsonConstructorExpr)) > + return true; > > I added the above codes, then the query returned the correct result. > I didn't dig more the details. Any thought?
Yeah, JsonConstructorExpr should not be treated as a non-strict construct. This fix looks correct to me.
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. But I got a different result on 16.6 for json_object, as below:
postgres=# select version(); version --------------------------------------------------------------------------------------------------------- PostgreSQL 16.6 on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu 11.4.0-1ubuntu1~22.04.2) 11.4.0, 64-bit
postgres=# SELECT sub.c FROM (SELECT json_object(3:2, t.c:1) AS c FROM t) AS sub RIGHT JOIN t ON FALSE; ERROR: null value not allowed for object key postgres=# SELECT sub.c FROM (SELECT json_object(3:2, 1:t.c) AS c FROM t) AS sub RIGHT JOIN t ON FALSE; c ----------------------- {"3" : 2, "1" : null} (1 row)
Shouldn't the result be NULL?
I attached my patch. In my patch, I only cover json_array/json_arrayagg/json_object/json_objectagg.
