Stdlib: array_udiff()/array_uintersect() callbacks must receive enum case objects (ext/standard/array.c)

[PurHur]

Category

stdlib

Problem

The array_udiff() / array_uintersect() / array_diff_uassoc() family is missing on the VM (#3129, #4285). When implemented, user compare callbacks must receive enum case objects, not backed scalars. Zend passes objects; coercing to 1/2 breaks identity comparisons and instanceof predicates.

php-src reference

• php/php-src ext/standard/array.c — php_array_udiff, php_array_uintersect, php_array_diff_uassoc

Repro (failure today: undefined function; spec for implementers)

<?php
enum E: int { case A = 1; case B = 2; }
$a = [E::A, E::B];
$b = [E::B];
var_export(array_udiff($a, $b, fn($x, $y) => ($x <=> $y)));

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php repro.php
./phpc run repro.php
'

Runtime	Today	After implementation
Zend	array (0 => E::A)	compare fn receives E::A, E::B objects
VM	Call to undefined function array_udiff()	must match Zend

Scope (this repo)

Area	Path
Stdlib	ext/standard/array_udiff.php (and uintersect/uassoc siblings)
VM	callback invocation — preserve enum tags in lib/VM.php
Blocked on	#3129, #4285 registration

Done when

• array_udiff repro returns one-element array with E::A object
• Callback test asserts get_debug_type($x) === 'E' inside comparator
• ./script/ci-fast.sh --filter array_udiff_enum green

Related

• Stdlib: array_udiff / array_diff_assoc / array_intersect_assoc family (ext/standard parity) #3129 — register array_udiff family
• Stdlib: array_map()/array_filter() on enum arrays must preserve enum case objects (ext/standard/array.c) #5564 — array_map/array_filter enum preservation

[PurHur]

claim: PHP Compiler STD Lib — starting this run

[PurHur]

Merged via #8103.

Root cause: VmArrayUserSetOps::guardOperands() called VmArray::rejectEnumCaseSetOpOperands() (intended for plain array_diff/array_intersect per #5927) on user-comparator builtins, rejecting enum case values before callbacks ran.

Fix: Drop that guard from the user-comparator path so enum case zvals reach closure/strcmp comparators like Zend.

Verification (VM + JIT):
```bash
./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php test/repro-maintainer/parity_array_udiff_enum.php
php bin/vm.php test/repro-maintainer/parity_array_udiff_enum.php
php bin/jit.php test/repro-maintainer/parity_array_udiff_enum.php
vendor/bin/phpunit --filter array_udiff_enum
'
```
All green — repro prints `1 / ok / true`; compliance `array_udiff_enum.phpt` passes on VM and JIT.

[PurHur]

claim: PHP Compiler STD Lib — starting this run (array_udiff/uintersect enum case preservation + compliance #5637)

[PurHur]

Merged via #8676

Root cause: compiler enum ClassConstFetch prefetch reused dead slot indices — (1) ordinal mapping attached unrelated fetches to call args like count($r), clobbering array_udiff() results; (2) inline [E::A, E::B] / [E::B] array literals mapped the wrong preceding fetch to [E::B]'s sole element (stored E::A).

Fix: guard call-arg prefetch + bind array elements to their own fetch operands; VM literal return resolution + enum <=> via compareEnumCasesForSort.

Verification (Docker):

• ./vendor/bin/phpunit --filter array_udiff_enum — VM + JIT OK
• php bin/vm.php test/repro-maintainer/parity_array_udiff_enum.php — OK
• php bin/compile.php -l test/repro-maintainer/parity_array_udiff_enum.php — AOT lint OK
• ./vendor/bin/phpunit --filter get_debug_type_enum — OK (Stdlib: get_debug_type() — enum cases must return enum class name (ext/standard/type.c parity) #4260 regression)