Re: ON ERROR in json_query and the like

On Thu, Jun 20, 2024 at 5:22 PM Amit Langote <amitlangote09@gmail.com>
wrote:

>
> Soft error handling *was* used for catching cast errors in the very
> early versions of this patch (long before I got involved and the
> infrastructure you mention got added).  It was taken out after Pavel
> said [1] that he didn't like producing NULL instead of throwing an
> error.  Not sure if Pavel's around but it would be good to know why he
> didn't like it at the time.
>
>
I'm personally in the "make it error" camp but "make it conform to the
standard" is a stronger membership (in general).

I see this note in your linked thread:

> By the standard, it is implementation-defined whether JSON parsing errors
> should be caught by ON ERROR clause.

Absent someone contradicting that claim I retract my position here and am
fine with failing if these "functions" are supplied with something that
cannot be cast to json.  I'd document them like functions that accept json
with the implications that any casting to json happens before the function
is called and thus its arguments do not apply to that step.

Given that we have "expression IS JSON" the ability to hack together a case
expression to get non-erroring behavior exists.

David J.