Stdlib: compact() must preserve enum case values not backed scalars (ext/standard/array.c)

[PurHur]

Category

stdlib

Problem

compact() builds an array from symbol-table variables. When a variable holds a backed enum case object, Zend keeps the enum case in the result array. This compiler coerces enum cases to their backing scalar (int/string), breaking identity and follow-on APIs (get_debug_type, instanceof, serialization).

php-src reference

• php/php-src ext/standard/array.c — PHP_FUNCTION(compact) / php_compact_var
• php/php-src Zend/zend_enum.c — enum case zvals are objects

Repro (verified 2026-06-04)

<?php
enum E: int { case A = 1; }
$a = E::A;
var_export(compact('a'));
echo "\n";

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

Runtime	Output
Zend	array ( 'a' => \E::A, )
VM	array ( 'a' => 1, )

Scope (this repo)

Area	Path
VM	ext/standard/compact.php or VmCompact helper — copy enum case objects verbatim
JIT/AOT	lib/JIT/Builtin/ compact lowering (pairs #5493 php-in-php migration)
C shrink	Completing #5493 should delete phpc_compact.c without reintroducing scalarization

Done when

• Repro var_export(compact('a')) matches Zend for backed and unit enums
• JIT/AOT compact path matches VM when enabled
• Compliance test/compliance/cases/stdlib/compact_enum_case.phpt green
• ./script/ci-fast.sh --filter compact_enum green

Related

• php-in-php: phpc_compact.c — delete ~270 lines, compact() VM+JIT from ext/standard #5493 — delete phpc_compact.c, PHP implementation
• Enum coercion cluster: Stdlib: get_debug_type() on enum cases — must return enum name not scalar (ext/standard/type.c, #3454) #5509 get_debug_type, Stdlib: get_class() on enum case must return enum name not false (ext/standard/basic_functions.c) #5484 get_class

[PurHur]

claim: PHP Runtime → PHP — starting this run (#5563 compact() enum case preservation in VmScope + JIT ScopeBuiltinHelper).

[PurHur]

Unclaiming #5563: master already preserves enum cases in compact() — VM+JIT repro green (\E::A). Adding compliance phpt and closing with #5493 verification.

[PurHur]

Merged via #7510.

Verification (green):

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && vendor/bin/phpunit --filter "CompactRuntimeShrinkTest|StreamContextRuntimeStandaloneTest|compact_enum_case"'
# OK (5 tests, 15 assertions)

C files confirmed absent from linker/tree. StreamContext standalone setLinkage fix applied.