Re: finish TODOs in to_json_is_immutable, to_jsonb_is_immutable also add tests on it

Hi Jian,

Thanks for working on this. The patch looks good, but I have a few
observations:

1. Index creation fails for range types regardless of the base data type:

postgres=# create type range_int as range(subtype=int);
CREATE TYPE
postgres=# create table range_table(r1 range_int);
CREATE TABLE
postgres=# create index on range_table(json_array(r1 returning jsonb));
ERROR: functions in index expression must be marked IMMUTABLE

I believe this is because range_out is a stable function. Consequently, the
following
code snippet in to_jsonb_is_immutable may be redundant, or should simply
return
false without recursing for the sub-type:

+ else if (att_typtype == TYPTYPE_RANGE)
+ {
+ to_jsonb_is_immutable(get_range_subtype(typoid), contain_mutable);
+ }

2. Regarding the function names to_jsonb_is_immutable and
to_json_is_immutable:
since these do not return a boolean value, "is" may no longer be
appropriate. Perhaps
something like to_jsonb_check_mutable would be more accurate?

Best regards,
Vaibhav Dalvi
EnterpriseDB

On Thu, Jan 8, 2026 at 12:35 PM jian he <jian(dot)universality(at)gmail(dot)com> wrote:

> hi.
>
> rebase due to conflict in
>
> https://git.postgresql.org/cgit/postgresql.git/commit/?id=ba75f717526cbaa9000b546aac456e43d03aaf53
>
>
> --
> jian
> https://www.enterprisedb.com/
>