libc: report complete locale information

[brandonpayton]

Why

A locale object tells the C standard library (libc) how to format language-dependent information such as month names. POSIX.1-2024 defines the behavior applications should observe when they query those objects.

Kandelo's POSIX.1-2024 locale surface reported invented or missing data: getlocalename_l() always returned "C" without reading the supplied locale object, and nl_langinfo_l() returned empty strings for the declared ALTMON_* and ABALTMON_* items. Locale-aware software and Homebrew build probes therefore could not observe the locale state that libc actually held.

This makes locale names truthful for local and global locale objects on both hosts and supplies the alternate-month fallback that musl's catalog model can represent.

What changed

• getlocalename_l() was a Kandelo stub rather than an implementation over musl's locale_t category maps.
• musl's private mixed-LC_ALL codec used ; as a delimiter even though ; is legal in musl locale names, so it could not meet POSIX's required same-process getlocalename_l(LC_ALL) -> setlocale(LC_ALL, ...) round trip for every valid name.
• A process-lifetime cache for composite names would grow with every combination queried. The finalized implementation instead keeps at most one composite-name entry per live non-global locale object and removes it under __locale_lock before successful in-place newlocale() mutation and before freelocale().

The shared serializer now uses /, which musl forbids inside locale names. The decoder requires exactly six nonempty, bounded fields and commits libc.global_locale only after every category has loaded, so malformed input cannot partially mutate process locale state. Legal semicolons remain ordinary locale-name data.

LC_GLOBAL_LOCALE mixed names use thread-local storage, matching POSIX's cross-thread pointer-lifetime requirement. Local-object results remain valid until the object is freed or successfully reused as a newlocale() base.

ALTMON_1..12 and ABALTMON_1..12 map to the existing full and abbreviated month catalog keys. This is documented as partial because musl catalogs do not encode a second grammatical month form.

Downstream coordination

Open PR #822 hardcodes Perl's target LC_ALL separator to musl's former ; representation. Before Perl is rebuilt with this libc, #822 (or the branch that absorbs it) must switch that target config and its assertions/docs to /, or avoid parsing the private representation. Existing statically linked binaries are unaffected. POSIX explicitly limits this encoding contract to round trips within the same process and permits the implementation-specific representation to change between builds.

ABI and artifacts

This changes statically linked libc behavior only. It does not change the kernel/host ABI, shared layouts, syscalls, Wasm exports, VFS metadata, or fork instrumentation. ABI_VERSION remains 18 and the ABI snapshot gate is clean. Programs and bottles must be rebuilt to consume the new libc behavior; no existing artifact is rewritten by this PR.

Validation

• ./scripts/dev-shell.sh bash scripts/build-musl.sh - passed (wasm32)
• ./scripts/dev-shell.sh bash scripts/build-musl.sh --arch wasm64posix - passed
• fixture compile with -Wall -Wextra -Werror and direct guest execution - locale-info-ok
• ./scripts/dev-shell.sh bash -c 'rm -rf host/dist; cd host && npx vitest run test/locale-info.test.ts' - 1 passed, 0 failed
• ./scripts/dev-shell.sh bash -c 'rm -rf host/dist; cd apps/browser-demos && KANDELO_PLAYWRIGHT_PORT=5417 npx playwright test test/locale-info.spec.ts --project=chromium' - 1 passed, 0 failed
• full libc suite - 303 passed, 0 failed, 20 expected failures, 1 known flaky, 324 total
• Open POSIX suite - 174 passed, 0 failed, 3 expected failures, 2 skipped, 179 total
• ./scripts/dev-shell.sh bash scripts/run-sortix-tests.sh --all - 5,035 passed, 0 failed, 19 expected failures, 52 skipped, 0 build failures, 0 timeouts, 5,106 total
• ./scripts/dev-shell.sh bash scripts/check-abi-version.sh - snapshot and ABI version consistent
• git diff --check origin/main..618f8d603 - clean

The focused Chromium run used the locally rebuilt ABI 18 kernel and fixture with a generated empty ABI 18 rootfs. The full host Vitest and aggregate browser suites were not run locally; CI remains the evidence for those broader surfaces.

An independent devil's-advocate review of commit 618f8d6031ed95bae4ab122cc6c98d99cdd96d6f found no blocking, high, or medium issues.

[brandonpayton]

CI setup classification for exact head 618f8d6031ed95bae4ab122cc6c98d99cdd96d6f:

The current file, gawk, and gzip matrix failures are GitHub Actions infrastructure failures, not package or locale failures. Each job exhausted retries resolving action download metadata and ended with Service Unavailable before any build command ran:

• file: https://github.com/Automattic/kandelo/actions/runs/29250324503/job/86822664181
• gawk: https://github.com/Automattic/kandelo/actions/runs/29250324503/job/86822664110
• gzip: https://github.com/Automattic/kandelo/actions/runs/29250324503/job/86822664212

The workflow is still running, so GitHub does not yet allow those jobs to be rerun. I will rerun the exact failed jobs once the run becomes eligible. This comment does not classify any later failure without inspecting its log.

[github-actions]

Phase B-1 matrix build status — pr-916-staging

ABI v18. 69 built, 0 failed, 69 total.

Package	Arch	Status	Sha
libcurl	wasm32	built	c2eb35c3
libcxx	wasm32	built	01454e96
libcxx	wasm64	built	17edecea
libpng	wasm32	built	9373ec07
libxml2	wasm32	built	29c66726
libxml2	wasm64	built	c465e980
openssl	wasm32	built	887151e1
openssl	wasm64	built	d233a2f2
sqlite	wasm32	built	548305b0
sqlite	wasm64	built	61788f0e
zlib	wasm32	built	4224cc4d
zlib	wasm64	built	a9bf6489
bc	wasm32	built	64949762
bzip2	wasm32	built	34c7aa1e
coreutils	wasm32	built	2344bdb3
curl	wasm32	built	aa69b5db
dash	wasm32	built	6c366450
diffutils	wasm32	built	32032bc8
dinit	wasm32	built	9ae1bce0
fbdoom	wasm32	built	ce3164e4
file	wasm32	built	11dba372
findutils	wasm32	built	f67592ae
gawk	wasm32	built	e54fdc61
git	wasm32	built	9b2d548d
grep	wasm32	built	fbf0203e
gzip	wasm32	built	b1c84007
hello	wasm32	built	eab596f0
kandelo-sdk	wasm32	built	f35dd048
kernel	wasm32	built	5203e0d9
less	wasm32	built	83900e94
lsof	wasm32	built	544d229c
m4	wasm32	built	233df978
make	wasm32	built	74046ca8
mariadb	wasm32	built	b4d8dcea
mariadb	wasm64	built	bdc57cfe
modeset	wasm32	built	dcac4290
msmtpd	wasm32	built	29ebf352
nano	wasm32	built	aeeb65e1
ncurses	wasm32	built	e7b60d2b
netcat	wasm32	built	6583d80f
nginx	wasm32	built	c6184ee2
php	wasm32	built	01f079da
posix-utils-lite	wasm32	built	4cc63712
ruby	wasm32	built	dcaf8e6a
sed	wasm32	built	8576502e
spidermonkey	wasm32	built	3de9f860
tar	wasm32	built	0f292535
tcl	wasm32	built	c02e9685
unzip	wasm32	built	a4ea44c9
userspace	wasm32	built	1af95362
vim	wasm32	built	d2117418
wget	wasm32	built	89cd8b4f
xz	wasm32	built	73d01c0f
zip	wasm32	built	7e48916b
zstd	wasm32	built	73150090
bash	wasm32	built	e3fd75d7
mariadb-test	wasm32	built	7e42fd81
mariadb-vfs	wasm32	built	14c8450f
mariadb-vfs	wasm64	built	92763175
nethack	wasm32	built	722e0fb7
node	wasm32	built	64ef67eb
spidermonkey-node	wasm32	built	e765fc51
vim-browser-bundle	wasm32	built	acd74781
nethack-browser-bundle	wasm32	built	1cbba481
rootfs	wasm32	built	f794d4ec
shell	wasm32	built	bd66f39b
lamp	wasm32	built	d086319f
node-vfs	wasm32	built	b21c4bd3
wordpress	wasm32	built	8344e0e9

_{Auto-generated; replaced on each push. Raw data in the publish-status workflow artifact.}

[brandonpayton]

Absorbed by rebase-merged #967. Main is now 6efb411 with the sealed tree b133bfa018f7e2bc84c4845edf2f945b2f844954, and ABI 41 activation completed successfully in run 29550069085. The absorption audit confirmed this PR\x27s behavior and tests are present in that merged tree, so this source PR is closed and its branch is deleted.