Follow-up of 🐛 Support multiple implementations for hook_field_widget_third_party_settings_form Active .
There is now a fatal error if a field_widget_third_party_settings_form hook doesn't return an array, such as entity_browser_entity_form_field_widget_third_party_settings_form(), which conditionally adds something only for a certain plugin.
Yes, it's documented as returning an array, but typically hooks don't require you to return something and it wasn't necessary until now. Breaks a fairly high profile contrib module, so creating a core issue instead of just fixing that. There are likely others.
Other exampes: sitestudio_default_helper, ai_translate_textfield, 5 pages of results, most do return an array.
Active
11.0 🔥
field system
A test would require another hook that returns nothing. I'm not sure that's really worth it.
I'm also not sure we actually want to support this. we could also explicitly deprecate a non-array return value.
either way, leaving at needs work to update the second place