Stdlib: WeakMap::offsetSet() must accept backed enum case keys (Zend/zend_weakrefs.c)

[PurHur]

Category

stdlib · language · php-src-strict

Problem

Zend treats backed enum case objects as valid WeakMap keys (weak-referenced like any object). This compiler rejects the assignment:

enum E: int { case A = 1; }
$m = new WeakMap();
$m[E::A] = 42;   // Zend: ok
echo $m[E::A];   // 42

VM throws TypeError: WeakMap key must be an object because enum cases are represented as backing scalars (int) and WeakMap only accepts TYPE_OBJECT.

php-src reference

• php/php-src Zend/zend_weakrefs.c — zend_weakmap_offset_set, object-key guard
• php/php-src Zend/zend_enum.c — enum case is IS_OBJECT

Repro

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php test/repro-maintainer/parity_weakmap_enum_case_key.php
php bin/vm.php test/repro-maintainer/parity_weakmap_enum_case_key.php 2>&1 | head -5
'

Runtime	$m[E::A] = 1
Zend	succeeds; offsetGet returns stored value
VM	TypeError: WeakMap key must be an object

Scope

Layer	Files
VM	lib/VM/WeakMapSupport.php (or equivalent) — accept TYPE_ENUM_CASE keys
Enum	lib/VM/EnumSupport.php — enum cases must be objects at runtime (pairs #8941)
JIT	lib/JIT/Builtin/WeakRefRegistryRuntime.php / WeakMap lowering
Tests	test/compliance/cases/stdlib/weakmap_enum_case_key.phpt

PHP-in-PHP: registry + offset handlers in PHP VM/JIT; shrink any C weakref tables when PHP path lands (#9191).

Done when

• Repro stores and retrieves value on VM like Zend
• Non-object scalars still TypeError
• ./script/ci-fast.sh --filter weakmap_enum_case_key green

Related

• Stdlib: WeakMap — VM offsetSet throws "Illegal offset" (Zend/zend_weakrefs.c parity) #4645 — general WeakMap offsetSet failures (orthogonal object-key bug)
• php-in-php: JIT WeakRefRegistryRuntime — route WeakMap/WeakReference registry through VmWeakRefRegistry PHP not phpc_weakref LLVM (#1492) #9191 — php-in-php WeakRef registry migration
• Stdlib: spl_object_id()/spl_object_hash() on enum case objects — must accept enum not backing scalar (ext/spl/php_spl.c) #8941 — spl_object_id() / enum case object acceptance
• North star: Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492

[PurHur]

claim: agent-lane-c — starting this run

[PurHur]

Already fixed on master — php bin/vm.php test/repro-maintainer/parity_weakmap_enum_case_key.php passes; weakmap_enum_case_key.phpt green. Unclaiming; no PR needed.

[PurHur]

claim: cursor-agent-lane-c — verifying fixed state and closing

[PurHur]

Lane C verification (2026-06-23): Already fixed on master — no code change required this run.

Verification:

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/vm.php test/repro-maintainer/parity_weakmap_enum_case_key.php
php bin/jit.php test/repro-maintainer/parity_weakmap_enum_case_key.php
php bin/vm.php -r "\$m=new WeakMap(); try { \$m[1]=1; } catch (Throwable \$e) { echo get_class(\$e); }"
vendor/bin/phpunit --filter weakmap_enum_case_key
'

Output:

• VM/JIT repro: set ok / 1 / isset yes
• Scalar key: TypeError
• PHPUnit: OK (1 test, 1 assertion)

Closes done-when for php-src-strict WeakMap enum case keys.