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Subject: Re: Remaining dependency on setlocale()
From: Chao Li <li.evan.chao@gmail.com>
In-Reply-To: <5f70ee8a3f73df753285f8928c01dd32f14d7fcb.camel@j-davis.com>
Date: Tue, 16 Dec 2025 09:32:09 +0800
Cc: Peter Eisentraut <peter@eisentraut.org>,
 Thomas Munro <thomas.munro@gmail.com>,
 Tom Lane <tgl@sss.pgh.pa.us>,
 pgsql-hackers@postgresql.org
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To: Jeff Davis <pgsql@j-davis.com>
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> On Dec 16, 2025, at 03:34, Jeff Davis <pgsql@j-davis.com> wrote:
>=20
> On Sat, 2025-12-13 at 17:48 +0800, Chao Li wrote:
>> 1 - 0001
>> ```
>> + int match_mblen pg_attribute_unused();
>> ```
>>=20
>> Why this variable is marked unused? It=E2=80=99s actually used.
>=20
> Fixed and committed.
>=20
> I originally marked it unused because I just had an:
>=20
>   Assert(match[match_mblen] =3D=3D '\0');
>=20
> but I changed it to just set it:
>=20
>   match[match_mblen] =3D '\0';
>=20
> for clarity, even though I think the underlying API guarantees NUL-
> termination.
>=20
>> 2 - 0002
>>=20
>> I did a search and found one place that you missed at line 181 in
>> pg_locale.h
>> ```
>> extern bool char_is_cased(char ch, pg_locale_t locale);
>> ```
>=20
> Thank you, fixed and committed.
>=20
>=20
> I'll continue committing v12 0003-0005. Note that I'm planning to
> backport 0003.

I have re-reviewed 0003-0005 last week, they all look good to me.

I have no comment on backport 0003.

>=20
> I'm also inclined to move forward with 0006. It's not a long-term
> solution, but it solves an instance of the problem under discussion in
> this thread (removes setlocale() dependency) and is a narrow fix.
>=20
>=20
> After that, remaining loose ends:
>=20
> * 0007: Can we just rip out the non-ASCII support? If it's gone all
> this time without UTF8 support, and there's no suggestion about what
> the non-ASCII behavior should be (in docs or source code), then it's
> probably not terribly important.
>=20
> * Use of pg_strncasecmp() in the backend, which uses tolower() to do
> case-insensitive matching of command options, e.g. "if
> (pg_strcasecmp(a, "plain") =3D=3D 0)" to check for PLAIN storage in =
CREATE
> TYPE.
>=20
> * strerror(): either consider an lc_ctype GUC, or the approach over
> here[1].
>=20
> * Daniel suggests that we need some way to set LC_COLLATE for
> extensions/dependencies.
>=20
> * address calls to pg_tolower in datetime.c and tzparser.c -- can =
those
> just be pg_ascii_tolower()?
>=20
> * examine remaining isalpha(), etc., calls in the backend
>=20
> Regards,
> Jeff Davis
>=20
> [1]
> =
https://www.postgresql.org/message-id/flat/90f176c5b85b9da26a3265b2630ece3=
552068566.camel@j-davis.com
>=20

I just reviewed 0006-0007. Only got one comment on 0006:

```
@@ -306,6 +342,7 @@ create_pg_locale_icu(Oid collid, MemoryContext =
context)
 	result =3D MemoryContextAllocZero(context, sizeof(struct =
pg_locale_struct));
 	result->icu.locale =3D MemoryContextStrdup(context, iculocstr);
 	result->icu.ucol =3D collator;
+	result->icu.lt =3D loc;
```

The old code didn=E2=80=99t create a locale object and store in result, =
thus it didn=E2=80=99t have a logic to free the created locale. This =
patch now dose that, but I don=E2=80=99t see where the created locale =
object is free-ed. I suppose newlocale() will allocate memory from the =
OS, so I guess the memory should be free-ed somewhere.

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/