Attempt to assign property "_attributes" on array

The test fails looks like it might be relataed, it is about a missing layout class. are we sure that's the right class, maybe just do an is_object check?

In our case #items does exist, but it's elements are arrays, not objects (\Drupal\bs_slider\Plugin\BsSliderBase::view replaces it). So this fix does work fine in terms of preventing the notice if I understand correctly.

Merged.

Automatically closed - issue fixed for 2 weeks with no activity.