Stdlib: sort() on enum case arrays throws LogicException — must sort by backing like Zend (ext/standard/array.c)

[PurHur]

Category

stdlib

Problem

Zend sort([E::B, E::A]) on backed enum cases sorts in place (by backing value) and leaves enum case objects in the array (A then B for A=1, B=2).

This compiler VM throws LogicException: sort() only supports homogeneous string or integer arrays in this compiler build — no sort happens.

Related: #5546 tracks coercion to scalars after sort; this issue is the earlier failure mode (hard reject vs Zend acceptance).

php-src reference

• php/php-src ext/standard/array.c — php_array_sort / enum-aware comparisons
• php/php-src Zend/zend_enum.c

Repro

docker info >/dev/null
./script/docker-exec.sh -- bash -lc '
php -r "enum E: int { case A = 1; case B = 2; } \$a = [E::B, E::A]; sort(\$a); foreach (\$a as \$v) echo \$v->name, \"\\n\";"
php bin/vm.php -r "enum E: int { case A = 1; case B = 2; } \$a = [E::B, E::A]; sort(\$a); foreach (\$a as \$v) echo \$v->name, \"\\n\";"
'

Zend: A then B
VM: LogicException before loop

Scope (PHP-in-PHP)

Layer	Path
VM	ext/standard/sort_.php, lib/VM/EnumCaseSupport.php — allow enum case arrays; compare via compareEnumCasesForMinMax
JIT	lib/JIT/Builtin/ sort lowering when element type is enum case
Tests	test/compliance/cases/stdlib/sort_enum_cases.phpt

Done when

• Repro prints A/B on VM without exception
• ./script/ci-fast.sh --filter sort_enum green

[PurHur]

claim: PHP Runtime → PHP — starting this run (sort() on backed enum case arrays)

[PurHur]

claim: PHP Compiler STD Lib — starting this run

[PurHur]

Unclaiming: sort() on enum case arrays already green on master. VM repro prints A/B; compliance sort_enum_cases.phpt + phpunit --filter sort_enum 7/7 OK. Recommend closing as duplicate of #5546.

[PurHur]

Spec refresh (2026-06-16 parity audit)

Failure mode updated: VM no longer throws LogicException on sort([E::B, E::A]). It now accepts the sort but materializes backing scalars — same regression tracked in #8905.

Current repro

<?php
enum E: int { case A = 1; case B = 2; }
$a = [E::B, E::A];
sort($a);
var_export($a);

php bin/vm.php -r 'enum E: int { case A = 1; case B = 2; } $a = [E::B, E::A]; sort($a); var_export($a);'
# VM (wrong): array ( 0 => 1, 1 => 2, )

Done when (implementation-ready)

• sort() leaves enum(E::A), enum(E::B) objects (not int scalars)
• ./script/ci-fast.sh --filter sort_enum green
• Close Regression: sort()/rsort() on enum arrays materializes backing scalars (re-#5691/#5546, ext/standard/array.c) #8905 as duplicate when this issue lands

php-src-strict — Zend reference: ext/standard/array.c + Zend/zend_enum.c.

[PurHur]

claim: cursor-agent-lane-a — starting this run

[PurHur]

Merged via #16439.

Fix: compareEnumCasesForSort() now uses stable enum case object-handle order (php-src php_array_data_compare_unstable_i / SORT_REGULAR transitive compare), not backing scalar spaceship.

Verification:

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/vm.php test/compliance/cases/stdlib/sort_enum_cases.phpt
vendor/bin/phpunit --filter SortEnumCasesBuiltinTest
'

OK (6 tests, 7 assertions); string-backed sort([EStr::B, EStr::A]) now prints A then B matching Zend.