Stdlib: iterator_to_array() — materialize Traversable/Generator (ext/spl parity)

[PurHur]

Category

stdlib

Status (refreshed 2026-06-02 — backlog-architect)

Phase 1 landed: iterator_to_array() is registered in ext/standard/Module.php. VM handles arrays and Generators via VM::iteratorToArray(); JIT handles compile-time Generator args via JitIteratorToArray.

Remaining gap (phase 2 → #4244): Iterator / IteratorAggregate objects still throw LogicException — see lib/VM.php:705-707.

Piece	Status
Builtin registered	✅
VM: array input	✅
VM: Generator input	✅
VM: Iterator/IteratorAggregate	❌ → #4244
JIT: runtime $preserve_keys	❌ (compile-time bool only)
JIT: Iterator objects	❌

Problem (original)

Zend iterator_to_array(Traversable $iterator, bool $preserve_keys = false) materializes any traversable into an array. Frameworks use it for generator→array conversion and SPL iterators.

php-src reference

• php/php-src ext/spl/iterator.c — PHP_FUNCTION(iterator_to_array)
• php/php-src Zend/zend_interfaces.c — zend_iterator_to_array()

Repro — Generator (passes today)

<?php
$g = (function () { yield 1; yield 2; })();
var_export(iterator_to_array($g));

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/vm.php -r "
\$g = (function () { yield 1; yield 2; })();
var_export(iterator_to_array(\$g));
"'

Engine	Result
Zend PHP 8.3+	array ( 0 => 1, 1 => 2, )
This compiler VM	✅ same (after phase 1)

Repro — Iterator object (still fails → #4244)

<?php
class OneShot implements Iterator {
    private bool $done = false;
    public function rewind(): void { $this->done = false; }
    public function valid(): bool { return !$this->done; }
    public function current(): int { return 42; }
    public function key(): int { return 0; }
    public function next(): void { $this->done = true; }
}
var_export(iterator_to_array(new OneShot()));

Actual: LogicException: iterator_to_array() argument must be an array or Generator

Scope (close this issue when)

• VM generator + array paths (ext/standard/iterator_to_array.php, lib/VM.php)
• Compliance PHPT for generator (test/compliance/cases/stdlib/iterator_to_array_generator.phpt or equivalent)
• Iterator objects → Stdlib: iterator_to_array() — Iterator/IteratorAggregate Traversable objects (phase 2 of #3100) #4244
• JIT runtime $preserve_keys (optional follow-up)

Done when (this issue)

• Generator repro green on VM
• Close after Stdlib: iterator_to_array() — Iterator/IteratorAggregate Traversable objects (phase 2 of #3100) #4244 lands Iterator/IteratorAggregate + update capability matrix

Related

• Stdlib: iterator_to_array() — Iterator/IteratorAggregate Traversable objects (phase 2 of #3100) #4244 — Iterator/IteratorAggregate phase 2
• Language: foreach over Traversable / Iterator objects (Zend parity) #3234 — foreach over Traversable (shared protocol)
• Language: Generator JIT lowering (yield opcodes) #3074 — Generator JIT

[PurHur]

claim: lane-b-worker — starting this run