Re: make tsearch use the database default locale

On 08.10.25 00:49, Jeff Davis wrote:
> Previously, tsearch used the database CTYPE for parsing, but that's not
> good because it creates an unnecessary dependency on libc even when the
> user has requested another provider.
>
> This patch series allows tsearch to use the database default locale for
> parsing. If the database collation is libc, there's no change.

This looks good to me overall.

> * Most of the patches are straightforward, but v1-0005 might need extra
> attention. There are quite a few cases there with subtle distinctions,
> and I might have missed something. For example, in the "C" locale,
> tsearch treats non-ascii characters as alpha, even though the libc
> functions do not do so (I preserved this behavior).

This is indeed a bit mysterious. AFAICT, the behavior you describe is
conditional on if (prs->usewide), so it apparently depends also on the
encoding? I'm not sure if the new code covers this.

After this patch set, char2wchar() can become a local function in
pg_locale_libc.c. (But we still need wchar2char() externally, so maybe
it's not worth changing this (yes).)