Re: Improve GetConfigOptionValues function

Bharath Rupireddy <bharath(dot)rupireddyforpostgres(at)gmail(dot)com> writes:
> On Mon, Jan 23, 2023 at 9:51 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Also, I intentionally dropped the GUC_NO_SHOW_ALL check in
>> get_explain_guc_options, because it seems redundant given
>> the preceding GUC_EXPLAIN check. It's unlikely we'd ever have
>> a variable that's marked both GUC_EXPLAIN and GUC_NO_SHOW_ALL ...
>> but if we did, shouldn't the former take precedence here anyway?

> You're right, but there's nothing that prevents users writing GUCs
> with GUC_EXPLAIN and GUC_NO_SHOW_ALL.

"Users"? You do realize those flags are only settable by C code,
right? Moreover, you haven't explained why it would be good that
you can't get at the behavior that a GUC is both shown in EXPLAIN
and not shown in SHOW ALL. If you want "not shown by either",
that's already accessible by setting only the GUC_NO_SHOW_ALL
flag. So I'd almost argue this is a bug fix, though I concede
it's a bit hard to imagine why somebody would want that choice.
Still, if we have two independent flags they should produce four
behaviors, not just three.

regards, tom lane