Re: PATCH: jsonpath string methods: lower, upper, initcap, l/r/btrim, replace, split_part - Mailing list pgsql-hackers

> On 22 May 2025, at 11:56 PM, Peter Eisentraut <peter@eisentraut.org> wrote:
>
> On 09.05.25 21:50, Robert Haas wrote:
>> I always struggle a bit to remember our policy on these issues -- to
>> the best of my knowledge, we haven't documented it anywhere, and I
>> think we probably should. I believe the way it works is that whenever
>> a function depends on the operating system's timestamp or locale
>> definitions, we decide it has to be stable, not immutable. We don't
>> expect those things to be updated very often, but we know sometimes
>> they do get updated.
>
> I don't understand how this discussion got to the conclusion that functions that depend on the locale cannot be
immutable. Note that the top-level functions lower, upper, and initcap themselves are immutable. 

I assume you mean that they’re set at initdb time, so there’s no mutability concern?