Re: remaining sql/json patches

On Tue, Sep 19, 2023 at 7:37 PM jian he <jian(dot)universality(at)gmail(dot)com> wrote:
> On Mon, Sep 18, 2023 at 7:51 PM Erik Rijkers <er(at)xs4all(dot)nl> wrote:
> >
> > and FYI: None of these crashes occur when I leave off the 'WITH WRAPPER'
> > clause.
> >
> > >
> > > Erik
> > >
>
> if specify with wrapper, then default behavior is keep quotes, so
> jexpr->omit_quotes will be false, which make val_string NULL.
> in ExecEvalJsonExprCoercion: InputFunctionCallSafe, val_string is
> NULL, flinfo->fn_strict is true, it will return: *op->resvalue =
> (Datum) 0. but at the same time *op->resnull is still false!
>
> if not specify with wrapper, then JsonPathQuery will return NULL.
> (because after apply the path_expression, cannot multiple SQL/JSON
> items)
>
> select json_query(jsonb'{"a":[{"a":3},{"a":[4,5]}]}','$.a[*].a?(@<=3)'
> returning int4range);
> also make server crash, because default is KEEP QUOTES, so in
> ExecEvalJsonExprCoercion jexpr->omit_quotes will be false.
> val_string will be NULL again as mentioned above.

That's right.

> another funny case:
> create domain domain_int4range int4range;
> select json_query(jsonb'{"a":[{"a":[2,3]},{"a":[4,5]}]}','$.a[*].a?(@<=3)'
> returning domain_int4range with wrapper);
>
> should I expect it to return [2,4) ?

This is what you'll get with v16 that I just posted.

> -------------------
> https://www.postgresql.org/docs/current/extend-type-system.html#EXTEND-TYPES-POLYMORPHIC
> >> When the return value of a function is declared as a polymorphic type, there must be at least one argument position that is also
> >> polymorphic, and the actual data type(s) supplied for the polymorphic arguments determine the actual result type for that call.
>
> select json_query(jsonb'{"a":[{"a":[2,3]},{"a":[4,5]}]}','$.a[*].a?(@<=3)'
> returning anyrange);
> should fail. Now it returns NULL. Maybe we can validate it in
> transformJsonFuncExpr?
> -------------------

I'm not sure whether we should make the parser complain about the
weird types being specified in RETURNING. The NULL you get in the
above example is because of the following error:

select json_query(jsonb'{"a":[{"a":[2,3]},{"a":[4,5]}]}','$.a[*].a?(@<=3)'
returning anyrange error on error);
ERROR: JSON path expression in JSON_QUERY should return singleton
item without wrapper
HINT: Use WITH WRAPPER clause to wrap SQL/JSON item sequence into array.

--
Thanks, Amit Langote
EDB: http://www.enterprisedb.com