Re: pg_collation.collversion for C.UTF-8

On Sun, Apr 23, 2023 at 5:22 AM Daniel Verite <daniel(at)manitou-mail(dot)org> wrote:
> I understand that my proposal to version C.* like any other collation
> might be erring on the side of caution, but ignoring these collation
> changes on at least one major OS does not feel right either.
> Maybe we should consider doing platform-dependent checks?

Hmm, OK let's explore that. What could we do that would be helpful
here, without affecting users of the "true" C.UTF-8 for the rest of
time? This is a Debian (+ downstream distro) only problem as far as
we know so far, and only for Debian 11 and older. Debian 12 was just
released the other day as the new stable, so the window of opportunity
to actually help anyone with our actions in this area is now beginning
to close, because we're really talking about new databases initdb'd
and new COLLATIONs CREATEd on Debian old stable after our next
(August) release. The window may be much wider for long term Ubuntu
releases. You're right that we could do something platform-specific
to help with that: we could change that code so that it captures the
version for C.* #if __GLIBC_MAJOR__ == 2 && __GLIBC_MINOR__ < 35 (or
we could parse the string returned by the runtime version function).
I don't recall immediately what our warning code does if it sees a
change from versioned to not versioned, but we could make sure it does
what you want here. That way we wouldn't burden all future users of
C.* with version warnings (because it'll be empty), but we'd catch
those doing Debian 11 -> 12 upgrades, and whatever Ubuntu upgrades
that corresponds to, etc. Is it worth it?