Raise exception and show message to user if repo missing satellite

app/controllers/merge_requests_controller.rb

@@ -69,6 +69,8 @@ class MergeRequestsController < ProjectResourceController
       @merge_request.check_if_can_be_merged
     end
     render json: {state: @merge_request.human_state}
+  rescue Gitlab::SatelliteNotExistError
+    render json: {state: :no_satellite}
   end
 
   def automerge

app/views/merge_requests/show/_mr_accept.html.haml

@@ -23,6 +23,11 @@
           .clearfix
 
 
+  .automerge_widget.no_satellite{style: "display:none"}
+    .alert.alert-error
+      %span
+        %strong This repository does not have satellite. Ask administrator to fix this issue
+
   .automerge_widget.cannot_be_merged{style: "display:none"}
     .alert.alert-info
       %span