Regression: Enum::cases() / UnitEnum::cases() returns empty array — re-#9682/#5462 (Zend/zend_enum.c)

[PurHur]

Category

language · php-src-strict · regression guard

Problem

BackedEnum::cases() and UnitEnum::cases() must return a list of enum case objects in declaration order. Closed #5462, #5507, and #9682 fixed this previously; VM regressed again — static call succeeds but returns array(0) { }.

Breaks spread/unpack ([...E::cases()]), reflection (#9606), iterators, and any bootstrap code enumerating enum cases.

php-src reference

• php/php-src Zend/zend_enum.c — zend_enum_list_cases, case table
• php/php-src Zend/zend_interfaces.c — UnitEnum::cases internal method
• Tests: Zend/tests/enums/backed_enum_cases.phpt, enum_cases.phpt

Repro (failure today)

<?php
enum E: int { case C = 3; case A = 1; case B = 2; }
var_export(E::cases());
echo count(E::cases()), "\n";
foreach (E::cases() as $case) {
    echo $case->name, " ";
}
echo "\n";

enum U { case A; case B; }
echo count(U::cases()), "\n";
echo U::cases()[0]->name, "\n";

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/vm.php repro_enum_cases.php'

Engine	Result
Zend PHP 8.2+	array(3){enum(E::C),enum(E::A),enum(E::B)}, prints 3, C A B, unit enum 2 + A
This compiler VM	array(0){}, prints 0, empty foreach, unit enum 0

Scope (PHP-in-PHP)

• lib/VM/Builtin/EnumCases.php — case list materialization from enum registry
• lib/VM.php / enum compile metadata — ensure enumCases table populated at class link
• JIT: lib/JIT/ enum cases() lowering must match VM list
• Compliance: test/compliance/cases/language/enum_cases_*.phpt

Done when

• Repro counts and case names match Zend (declaration order C A B)
• test/unit/VmEnumCasesEmptyTableTest.php green
• Enum-case spread PHPTs green (Language: array spread in array literal with enum case list coerces to backing scalars (zend_execute.c) #5583)
• ReflectionEnum::getCases() unblocked when Stdlib: ReflectionEnum::getCases() returns empty — must list ReflectionEnumCase objects (ext/reflection/php_reflection.c) #9606 lands

Related

• Regression: UnitEnum::cases()/BackedEnum::cases() returns empty — re-#5462/#5507 (Zend/zend_enum.c) #9682 (closed) · Stdlib: ReflectionEnum::getCases() returns empty — must list ReflectionEnumCase objects (ext/reflection/php_reflection.c) #9606 reflection · Regression: backed enum E::Case yields backing scalars not enum objects (re-#9111, Zend/zend_enum.c) #9676 enum object representation · Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492

[PurHur]

claim: PHP Compiler STD Lib — starting this run

[PurHur]

Verified on master: repro and VmEnumCasesEmptyTableTest are green (VM returns C/A/B in declaration order). Regression appears already fixed. Handing off — picking #9878 instead.

[PurHur]

Closing as stale: green on master 2026-06-23.

vendor/bin/phpunit --filter VmEnumCasesEmptyTableTest → OK (1 test, 3 assertions).
Prior verification comments confirmed Enum::cases() returns case objects.