Re: CREATE COLLATION does not sanitize ICU's BCP 47 language tags. Should it?

On Tue, Sep 19, 2017 at 2:22 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Andreas Karlsson <andreas(at)proxel(dot)se> writes:
>> Hm, I like the idea but I see some issues.
>
>> Enforcing the BCP47 seems like a good thing to me. I do not see any
>> reason to allow input with syntax errors. The issue though is that we do
>> not want to break people's databases when they upgrade to PostgreSQL 11.
>> What if they have specified the locale in the old non-ICU format or they
>> have a bogus value and we then error out on pg_upgrade or pg_restore?
>
> Well, if PG10 shipped with that restriction in place then it wouldn't
> be an issue ;-)

I was proposing that this be treated as an open item for v10; sorry if
I was unclear on that. Much like the "ICU locales vs. ICU collations
within pg_collation" issue, this seems like the kind of thing that we
ought to go out of our way to get right in the *first* version.

--
Peter Geoghegan