Hyper model's `while_loading` does not work when loading scopes

[catmando]

# add this to the while_loading spec, and watch it fail!
...
   FactoryBot.create(:user, first_name: 'Lily', last_name: 'DaDog')
   FactoryBot.create(:user, first_name: 'Coffee', last_name: 'Boxer')
...
it "while loading works with relationships" do
   ReactiveRecord::Operations::Fetch.semaphore.synchronize do
     mount "WhileLoadingTester", {}, no_wait: true do
       class MyComponent < HyperComponent
         render do
           SPAN { 'loading...' }
         end
       end
       class WhileLoadingTester < HyperComponent
         render do
           UL do
             User.each { |user| LI { user.last_name } }
           end
           .while_loading 'loading...'
         end
       end
     end
     expect(page).to have_content('loading...')
     expect(page).not_to have_content('DaDog', wait: 0)
   end
   expect(page).to have_content('DaDog')
   expect(page).not_to have_content('loading...', wait: 0)
 end

last line of spec fails...

[catmando]

problem is that the WhileLoading assumes the number of loaded children stays constant. In this case it does not!

[catmando]

closed as part of changing while loading to use error boundries (it also fixed in the deprecated while_loading code, but who cares)