Horton

Re: Remaining dependency on setlocale()

Peter Eisentraut <peter@eisentraut.org>

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From: Peter Eisentraut <peter@eisentraut.org>
To: Jeff Davis <pgsql@j-davis.com>, Thomas Munro <thomas.munro@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers@postgresql.org
Date: 2025-06-10T15:32:01Z
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 07.06.25 00:23, Jeff Davis wrote:
> On Thu, 2025-06-05 at 22:15 -0700, Jeff Davis wrote:
>> To continue this thread, I did a symbol search in the meson build
>> directory like (patterns.txt attached):
> 
> Attached a rough patch series which does what everyone seemed to agree
> on:
> 
>    * Change some trivial ASCII cases to use pg_ascii_* variants
>    * Set LC_COLLATE and LC_CTYPE to C with pg_perm_setlocale
>    * Introduce a new global_lc_ctype for callers that still need to use
> operations that depend on datctype

v1-0001-copyfromparse.c-use-pg_ascii_tolower-rather-than-.patch
v1-0002-contrib-spi-refint.c-use-pg_ascii_tolower-instead.patch
v1-0003-isn.c-use-pg_ascii_toupper-instead-of-toupper.patch
v1-0004-inet_net_pton.c-use-pg_ascii_tolower-rather-than-.patch

These look good to me.

v1-0005-Add-global_lc_ctype-to-hold-locale_t-for-datctype.patch

This looks ok (but might depend on how patch 0006 turns out).

v1-0006-Use-global_lc_ctype-for-callers-of-locale-aware-f.patch

I think these need further individual analysis and explanation why these 
should use the global lc_ctype setting.  For example, you could argue 
that the SQL-callable soundex(text) function should use the collation 
object of its input value, not the global locale.  But furthermore, 
soundex_code() could actually just use pg_ascii_toupper() instead.  And 
in ts_locale.c, the isalnum_l() call should use mylocale that already 
exists in that function.  The problem to solve it getting a good value 
into mylocale.  Using the global setting confuses the issue a bit, I think.

v1-0007-Fix-the-last-remaining-callers-relying-on-setloca.patch

Do we have any data what platforms we'd need these checks for?

Also, if you look into wparser_def.c what p_isxdigit is used for, it's 
used for parsing XML (presumably HTML) files, so we just need ASCII-only 
behavior and no locale dependency.

v1-0008-Set-process-LC_COLLATE-C-and-LC_CTYPE-C.patch

As I mentioned earlier in the thread, I don't think we can do this for 
LC_CTYPE, because otherwise system error messages would not come out in 
the right encoding.  For the LC_COLLATE settings, I think we could just 
do the setting in main(), where the other non-database-specific locale 
categories are set.