Stdlib: mb_trim()/mb_ltrim()/mb_rtrim() — PHP 8.4 named `characters` param + new builtins (ext/mbstring/mbstring.c)

[PurHur]

Category

stdlib · php-src-strict · PHP 8.4

Problem

PHP 8.4 adds mb_trim(), mb_ltrim(), mb_rtrim() with a named characters parameter (distinct from legacy trim() charlist rules). This compiler implements the functions on VM but parity vs php-src must cover:

• named characters: argument binding (not confused with encoding:)
• encoding: named parameter when both appear
• empty/unicode charlist edge cases matching ext/mbstring

Maintainer repro: test/repro/maintainer_gap_mb_trim_named_characters.php

php-src reference

• php/php-src ext/mbstring/mbstring.c — mb_trim, mb_ltrim, mb_rtrim
• php/php-src ext/mbstring/mbstring.stub.php — signatures

Repro

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/vm.php test/repro/maintainer_gap_mb_trim_named_characters.php
# Compare output to Zend PHP 8.4+ on same script
'

<?php
$s = '--héllo--';
var_dump(mb_trim($s, '-'));
var_dump(mb_trim($s, characters: '-'));
var_dump(mb_ltrim($s, characters: '-'));
var_dump(mb_rtrim($s, characters: '-'));
var_dump(mb_trim($s, encoding: 'UTF-8'));

Scope (PHP-in-PHP)

Path	Work
ext/mbstring/mb_trim.php, mb_ltrim.php, mb_rtrim.php	VM implementations
ext/mbstring/Module.php	registration
lib/JIT/Builtin/	defer or route through VmMbstring PHP
script/capability-matrix.php	matrix row

Done when

• Repro dumps match Zend PHP 8.4+ on VM (php-src-strict)
• Positional + named characters/encoding combinations tested
• Compliance test/compliance/cases/stdlib/mb_trim_named.phpt green

Related

• Stdlib: mb_trim()/mb_ltrim()/mb_rtrim() named parameters rejected — LogicException not trimmed string (ext/mbstring/mbstring.c) #9839 (if split) · Stdlib: show_source() — alias of highlight_file() (ext/standard/url.c parity) #3447 mbstring parity · #1492

[PurHur]

claim: cursor-agent-lane-c — starting this run

[PurHur]

Merged via #15714.

Fix: supportsMbTrimFunctions() now gates on languageProfileVersion() (same pattern as #15706 HTTP header builtins) so mb_trim/mb_ltrim/mb_rtrim register under PHP_COMPILER_PROFILE=8.4. Named characters: / encoding: lowering was already correct in BuiltinParamNames + VmMbstring::runTrimBuiltin().

Verify:

php bin/vm.php test/compliance/cases/stdlib/mb_trim_phantom.phpt          # ok (reference profile)
PHP_COMPILER_PROFILE=8.4 php bin/vm.php test/repro/maintainer_gap_mb_trim_named_characters.php  # ok
PHP_COMPILER_PROFILE=8.4 vendor/bin/phpunit --filter mb_trim_named        # OK (Docker)