Stdlib: mb_ucwords() still missing on PROFILE=8.4 (re-#20799, ext/mbstring/mbstring.c)

[PurHur]

Category

stdlib · php-src-strict · PHP 8.4 mbstring case helpers (pillar 4)

Problem

#20799 closed 2026-07-19, but master still has no mb_ucwords() under PHP_COMPILER_PROFILE=8.4 while sibling helpers (mb_ucfirst, mb_trim, …) register. Probed 2026-07-20 in Docker.

Repro	Zend 8.4 + mbstring	VM PROFILE=8.4 (2026-07-20)
function_exists('mb_ucfirst')	true	true
function_exists('mb_ucwords')	true	false
mb_ucwords('hello world')	Hello World	Error: undefined function

php-src reference

• php/php-src ext/mbstring/mbstring.c — PHP_FUNCTION(mb_ucwords)
• php/php-src ext/mbstring/mbstring.stub.php — mb_ucwords stub

PHP implementation target

• Add ext/mbstring/mb_ucwords.php mirroring mb_ucfirst / mb_convert_case paths
• Register in ext/mbstring/Module.php with the same forward-profile gate as mb_ucfirst
• PHP-in-PHP; no new C in runtime/

Repro

./script/docker-exec.sh -- bash -lc 'export PHP_COMPILER_PROFILE=8.4
php bin/vm.php test/repro/maintainer_gap_mb_ucwords_missing_forward84.php'

Expect mb_ucwords=yes and Hello World, not fail: undefined mb_ucwords.

Done when

• function_exists('mb_ucwords') true under PHP_COMPILER_PROFILE=8.4
• mb_ucwords('hello world') → Hello World (encoding arg parity with Zend)
• VM/JIT/AOT agree when mbstring lowering is in scope
• Compliance .phpt under test/compliance/cases/mbstring/; php-src-strict

[PurHur]

claim: PHP Compiler STD Lib — starting this run

Pillar 1: inventory OK; user_release_ready: yes (release-readiness quick).

Repro: function_exists('mb_ucwords') false under PHP_COMPILER_PROFILE=8.4; mb_ucfirst exists.

Implementing ext/mbstring/mb_ucwords.php + Module registration mirroring mb_ucfirst.

[PurHur]

claim: PHP Compiler Ext — I/O & Crypto — starting this run

[PurHur]

Merged via #21407

Verification:

• PHP_COMPILER_PROFILE=8.4 php bin/vm.php test/repro/maintainer_gap_mb_ucwords_missing_forward84.php → mb_ucwords=yes, Hello World
• VM compliance PHPTs under test/compliance/cases/mbstring/mb_ucwords_* green on reference + forward profile
• php script/bootstrap-inventory.php --check → OK 6162/6162; spine sync OK

[PurHur]

Merged via #21409

Verification: PHP_COMPILER_PROFILE=8.4 php bin/vm.php test/repro/maintainer_gap_mb_ucwords_missing_forward84.php → mb_ucwords=yes + Hello World; VM compliance --filter mb_ucwords (4 tests); inventory 6162/6162; ci-fast.sh green.

JIT/AOT lowering deferred (same VM-only path as mb_ucfirst).