skip n+1 on linkable images in content#edit

Author: drusepth

app/controllers/content_controller.rb

@@ -152,6 +152,10 @@ def edit
       return redirect_to @content, notice: t(:no_do_permission)
     end
 
+    @random_image_including_private_pool_cache = ImageUpload.where(
+      user_id: current_user.id,
+    ).group_by { |image| [image.content_type, image.content_id] }
+
     respond_to do |format|
       format.html { render 'content/edit', locals: { content: @content } }
       format.json { render json: @content }

app/views/content/form/field_types/_migration_link.html.erb

@@ -30,8 +30,13 @@
             )
           %>
           <% @linkables_raw.fetch(page_type.name, []).each do |linkable| %>
+            <%
+              linkable_image = @random_image_including_private_pool_cache.fetch([linkable.page_type, linkable.id], [])
+                .sample
+                .try(:src, :thumb) || asset_path("card-headers/#{linkable.page_type.downcase.pluralize}.jpg")
+            %>
             <option value="<%= page_type %>-<%= linkable.id %>"
-              data-icon="<%= asset_path linkable.random_image_including_private(format: :thumb) %>"
+              data-icon="<%= asset_path linkable_image %>"
               <%= 'selected' if field[:value].include?("#{page_type}-#{linkable.id}") %>
             >
               <%= linkable.name %>