name : FieldsetRecursionStack.php <?php namespace Statamic\Fields; use Illuminate\Support\Collection; use Statamic\Exceptions\FieldsetRecursionException; class FieldsetRecursionStack { public function __construct(private Collection $stack) { $this->stack = collect(); } public function push(string $import) { if ($this->stack->contains($import)) { throw new FieldsetRecursionException($import, $this->stack->last()); } $this->stack->push($import); } public function pop() { $this->stack->pop(); } }