Stdlib: lcfirst() — enum case operand must TypeError not silent coerce (ext/standard/string.c, php-src-strict)

[PurHur]

Category

stdlib

Problem

Under php-src-strict, string builtins must reject backed/unit enum case objects with TypeError (see #5780 hash family, #5861 ucfirst/nl2br sweep). lcfirst() still coerces enum cases via backing string on VM/JIT/AOT instead of raising:

TypeError: lcfirst(): Argument #1 ($string) must be of type string, E given

Sibling #5861 tracks ucfirst/nl2br/str_pad/addslashes; this issue is the lcfirst() gap verified independently.

php-src reference

• php/php-src ext/standard/string.c — PHP_FUNCTION(lcfirst) — Z_PARAM_STR rejects IS_OBJECT enum cases
• php/php-src Zend/zend_enum.c — enum case object type

Repro (verified 2026-06-05)

<?php
enum E: string { case A = 'hello'; }
try {
    lcfirst(E::A);
    echo "ok\n";
} catch (Throwable $t) {
    echo get_class($t), ': ', $t->getMessage(), "\n";
}

docker info >/dev/null
./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php8.2 repro.php
php bin/vm.php repro.php
php bin/jit.php repro.php 2>/dev/null || true
'

Runtime	Output
Zend PHP 8.2+	TypeError: lcfirst(): Argument #1 ($string) must be of type string, E given
vm.php today	ok (silent coerce via backing string 'hello')

Scope (PHP-in-PHP)

Path	Work
ext/standard/lcfirst.php	VM: VmString::coerceStringBuiltinArg() / EnumCaseSupport::isEnumCaseVariable() guard
lib/JIT/JitStringBuiltinArg.php	JIT/AOT: mirror VM guard (no C-only shortcut)
test/compliance/cases/stdlib/lcfirst_enum_type_error.phpt	VM compliance
test/compliance/cases/stdlib/lcfirst_enum_type_error_jit.phpt	JIT when LLVM available

Do not add logic to runtime/*.c. Delete any C fast-path that bypasses enum-case rejection.

Done when

• Repro prints TypeError on VM (not ok)
• JIT/AOT paths match VM (php-src-strict; no php-compiler-strict without proof)
• ./script/ci-fast.sh --filter lcfirst_enum green
• Compliance .phpt files added under test/compliance/cases/stdlib/

Related

• Stdlib: str_pad/addslashes/nl2br/ucfirst — enum case operands must TypeError (ext/standard/string.c) #5861 ucfirst/nl2br enum sweep (phase 2 of Stdlib: string builtins must TypeError on enum case operands (ext/standard/string.c) #5524)
• Stdlib: hash()/hash_hmac()/md5()/sha1()/crc32() — enum case operands must TypeError (ext/hash, ext/standard) #5780 php-src-strict umbrella for hash builtins
• Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492 north star

[PurHur]

claim: PHP Compiler STD Lib — starting this run

[PurHur]

Unclaiming: lcfirst() enum TypeError already green on master (#6220). VM repro prints TypeError; compliance PHPT lcfirst_enum_typeerror* exists. Closing as duplicate unless repro differs.

[PurHur]

claim: PHP Runtime → PHP — starting this run (lcfirst enum operand TypeError, php-src-strict #6003). Supersedes brief #5945 triage — that path already green.

[PurHur]

Verified green on master VM/JIT — added lcfirst_enum_type_error.phpt in PR (arrow-function overlay run).