Updating Many to Many?

[jakejohns]

I'm very confused about updating many to many relationships. This is possibly related to #105.

I would think I could just do something like the following:

$instructor_ids = $input['instructor_ids'] ?? [];
unset($input['instructor_ids']);

$session = $atlas->fetchRecord(
    Session::class,
    $session_id,
    ['instructors']
);

$session->instructors = $atlas->fetchRecordset(
    Instructors::class,
    $instructor_ids
);

$session->set($input);
$atlas->persis($session);

But I was unable to make anything even remotely like that work. I ended up having to do this?

$instructor_ids = $input['instructor_ids'] ?? [];
unset($input['instructor_ids']);


$session = $atlas->fetchRecord(
    Session::class,
    $session_id,
    ['instructors']
);

$current = array_map(
    function ($inst) {
        return $inst['instructor_id'];
    },
    $session->instructors->getArrayCopy()
);

// Delete some
foreach ($current as $cur) {
    if (! in_array($cur, $instructor_ids)) {
        $session->instructs->getOneBy(['instructor_id' => $cur])
            ->setDelete();

        $session->instructors->detachOneBy(['instructor_id' => $cur]);
    }
}

// Add some
foreach ($instructor_ids as $instructor_id) {
    if (! in_array($instructor_id, $current)) {
        $session->instructs[] = $this->atlas->newRecord(
            Instruct::class,
            [
                'session_id' => $session->session_id,
                'instructor_id' => $instructor_id
            ]
        );
    }
}

$session->set($input);

$atlas->persist($session);

I feel like I must be missing something, but pouring over the documentation and many attempts only resulted in various exceptions and errors.

Any insight?