Stdlib: array_reduce() on enum case arrays — closure callbacks must preserve enum objects (ext/standard/array.c)

[PurHur]

Category

stdlib

Problem

array_reduce() with a closure callback over [E::A, E::B] must return the enum case object selected by the callback (Zend). This compiler rejects closure callbacks with LogicException (array_reduce() callback must be a string user-function name). Even after #3086 enables closure callbacks, enum arrays must not coerce case objects to backing scalars between folds.

php-src reference

• php/php-src ext/standard/array.c — PHP_FUNCTION(array_reduce)

Repro

<?php
enum E: int { case A = 1; case B = 2; }
$cases = [E::A, E::B];
$r = array_reduce($cases, function ($carry, $item) {
    return $carry === null ? $item : $item;
});
var_export($r);
echo "\n";

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

Runtime	Expected
Zend	E::A (enum object)
VM today	LogicException (closure deferred)

Scope

• ext/standard/array_reduce.php — closure path (feat(vm): closure callbacks in array_map, array_filter, usort (#72) #3086)
• Enum preservation in fold iterator (same family as Stdlib: array_map()/array_filter() on enum arrays must preserve enum case objects (ext/standard/array.c) #5564 array_map)
• test/compliance/cases/stdlib/array_reduce_enum.phpt

Done when

• Repro prints enum case object identity on VM
• ./script/ci-fast.sh --filter array_reduce_enum green

Related

• feat(vm): closure callbacks in array_map, array_filter, usort (#72) #3086 — closure callbacks for array_*
• Stdlib: array_map()/array_filter() on enum arrays must preserve enum case objects (ext/standard/array.c) #5564 — array_map/filter enum preservation

[PurHur]

claim: worker-lane-b — starting this run

Gate snapshot (pre-work)

• docker info: OK
• bootstrap-inventory --check: OK (release-readiness; noted VmSocket construct-flag drift vs committed md)
• release-readiness: in progress (north-star5-verify --fast); will paste final JSON when lock clears

Implementing array_reduce enum-object preservation (#5626).

[PurHur]

Merged: #20012

Verification

• php bin/vm.php / php bin/jit.php test/repro/issue_5626_array_reduce_enum.php — \E::B + 0:A/1:B (Zend match)
• vendor/bin/phpunit test/compliance/VMTest.php --filter array_reduce — OK (10)
• vendor/bin/phpunit test/compliance/JITTest.php --filter array_reduce — OK (9)

Root cause: inline array_reduce([...], fn, []) ARG_SEND rebound the initial [] to the input INIT_ARRAY when the input Array_ was inferred:unknown (enum cases). Fix in lib/Compiler.php hoist + ARG_SEND ordinal wiring.