Re: Remaining dependency on setlocale()

Jeff Davis <pgsql@j-davis.com>

From: Jeff Davis <pgsql@j-davis.com>
To: Thomas Munro <thomas.munro@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-hackers@postgresql.org
Date: 2024-08-14T01:05:23Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →
  1. fuzzystrmatch: use pg_ascii_toupper().

  2. Avoid global LC_CTYPE dependency in pg_locale_icu.c.

  3. downcase_identifier(): use method table from locale provider.

  4. ltree: fix case-insensitive matching.

  5. Fix multibyte issue in ltree_strncasecmp().

  6. Use multibyte-aware extraction of pattern prefixes.

  7. Add pg_iswcased().

  8. Remove char_tolower() API.

  9. Make regex "max_chr" depend on encoding, not provider.

  10. Change some callers to use pg_ascii_toupper().

  11. Allow pg_locale_t APIs to work when ctype_is_c.

  12. Add #define for UNICODE_CASEMAP_BUFSZ.

  13. Inline pg_ascii_tolower() and pg_ascii_toupper().

  14. Avoid global LC_CTYPE dependency in pg_locale_libc.c.

  15. Force LC_COLLATE to C in postmaster.

  16. Change wchar2char() and char2wchar() to accept a locale_t.

  17. Use pg_ascii_tolower()/pg_ascii_toupper() where appropriate.

  18. inet_net_pton.c: use pg_ascii_tolower() rather than tolower().

  19. isn.c: use pg_ascii_toupper() instead of toupper().

  20. contrib/spi/refint.c: use pg_ascii_tolower() instead.

  21. copyfromparse.c: use pg_ascii_tolower() rather than tolower().

  22. Revert "Tidy up locale thread safety in ECPG library."

  23. Tidy up locale thread safety in ECPG library.

  24. All supported systems have locale_t.

On Sat, 2024-08-10 at 09:42 +1200, Thomas Munro wrote:
> The NetBSD situation is more vexing.  I was trying to find out if
> someone is working on it and unfortunately it looks like there is a
> principled stand against adding it:
> 
> https://mail-index.netbsd.org/tech-userlevel/2015/12/28/msg009546.html
> https://mail-index.netbsd.org/netbsd-users/2017/02/14/msg019352.html

The objection seems to be very general: that uselocale() modifies the
thread state and affects calls a long distance from uselocale(). I
don't disagree with the general sentiment. But in effect, that just
prevents people migrating away from setlocale(), to which the same
argument applies, and is additionally thread-unsafe.

The only alternative is to essentially ban the use of non-_l variants,
which is fine I suppose, but causes a fair amount of code churn.

> They're right that we really just want to use "C" in some places, and
> their LC_C_LOCALE is a very useful system-provided value to be able
> to
> pass into _l functions.  It's a shame it's non-standard, because
> without it you have to allocate a locale_t for "C" and keep it
> somewhere to feed to _l functions...

If we're going to do that, why not just have ascii-only variants of our
own? pg_ascii_isspace(...) is at least as readable as isspace_l(...,
LC_C_LOCALE).

Regards,
	Jeff Davis