Add Morph Many to Many (across a join table)

[atrauzzi]

It looks like I'm not able to map a many-to-many relationship across a join table using Laravel polymorphic relations.

I can however simulate half the solution by shoehorning a where clause into my relation method:

(the polymorphic columns are stored on the join table, and the join table goes out on a normal relation to the other class, although it might be nice to have double polymorphic relations in the future too!)

public function roles() {
return $this
    ->belongsToMany(
        'MyNamespace\MyPackage\Model\Role',
        'table_memberships',
        'authorizable_id'
        )
        ->where('authorizable_type', '=', get_called_class())
    ;
}

...unfortunately this doesn't set the string when calling save(). I suspect this is just a matter of combining the current many-to-many relation with a sprinkle of the morph-one-or-many or morph-many classes.

[atrauzzi]

Right now I can create morph-many-to-many records by manually instantiating a related model:

$vegetarianMembership = new MyNamespace\MyPackage\Model\Membership();
$vegetarian->memberships()->save($vegetarianMembership);
$user->memberships()->save($vegetarianMembership);

But again, it would obviously be nicer if I could more simply go:

$user->roles()->attach($vegetarian);

[atrauzzi]

See the following (as well as the migration and other model classes) project to get a better idea of how this could work: https://github.com/atrauzzi/authoritaire/blob/master/src/Atrauzzi/Authoritaire/Model/Authorizable.php