Re: BUG #18809: Inconsistent JSON behavoir

"David G. Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com> writes:
> On Wednesday, February 12, 2025, PG Bug reporting form <
> noreply(at)postgresql(dot)org> wrote:
>> broadway=# select jsonb('[2,3,1]') - to_jsonb(1);
>> ERROR: operator does not exist: jsonb - jsonb
>> LINE 1: select jsonb('[2,3,1]') - to_jsonb(1);

> This would be a feature request, not a bug report.

Indeed. We have these cases today:

postgres=# \do -
List of operators
Schema | Name | Left arg type | Right arg type | Result type | Description
------------+------+-----------------------------+-----------------------------+-----------------------------+-------------------------------------
...
pg_catalog | - | jsonb | integer | jsonb | delete array element
pg_catalog | - | jsonb | text | jsonb | delete object field
pg_catalog | - | jsonb | text[] | jsonb | delete object fields
...

These are already less than consistent, for example this is allowed:

postgres=# select jsonb('[2,3,1]') - 'foo'::text;
?column?
-----------
[2, 3, 1]
(1 row)

but this not so much:

postgres=# select jsonb('{"a": 1, "b": 2}') - 1;
ERROR: cannot delete from object using integer index

To invent jsonb - jsonb, you'd need to define its behavior for
every possible JSON structure on each side. I foresee plenty of
bikeshedding.

regards, tom lane