FIX: Display large/broken image placeholders for image oneboxes

lib/cooked_post_processor.rb

@@ -177,8 +177,6 @@ class CookedPostProcessor
     @doc.css("img[src^='data']") -
     # minus emojis
     @doc.css("img.emoji") -
-    # minus oneboxed images
-    oneboxed_images -
     # minus images inside quotes
     @doc.css(".quote img")
   end
@@ -410,9 +408,12 @@ class CookedPostProcessor
       next if img["src"].blank?
 
       src = img["src"].sub(/^https?:/i, "")
+      parent = img.parent
+      img_classes = (img["class"] || "").split(" ")
+      link_classes = ((parent&.name == "a" && parent["class"]) || "").split(" ")
 
       if large_images.include?(src) || broken_images.include?(src)
-        img.remove
+        img.remove unless img_classes.include?("onebox") || link_classes.include?("onebox")
         next
       end
 
@@ -426,7 +427,7 @@ class CookedPostProcessor
 
       next if img["class"]&.include?('onebox-avatar')
 
-      parent_class = img.parent && img.parent["class"]
+      parent_class = parent && parent["class"]
       width = img["width"].to_i
       height = img["height"].to_i
 

spec/components/cooked_post_processor_spec.rb

@@ -531,6 +531,24 @@ describe CookedPostProcessor do
 
       expect(cpp.doc.to_s).to eq("<p><img class=\"onebox\" src=\"#{upload.url}\" width=\"\" height=\"\"></p>")
     end
+
+    it "replaces large image placeholder" do
+      url = 'https://image.com/my-avatar'
+      image_url = 'https://image.com/avatar.png'
+
+      Oneboxer.stubs(:onebox).with(url, anything).returns("<img class='onebox' src='#{image_url}' />")
+
+      post = Fabricate(:post, raw: url)
+
+      post.custom_fields[Post::LARGE_IMAGES] = "[\"//image.com/avatar.png\"]"
+      post.save_custom_fields
+
+      cpp = CookedPostProcessor.new(post, invalidate_oneboxes: true)
+      cpp.post_process_oneboxes
+      cpp.post_process_images
+
+      expect(cpp.doc.to_s).to match(/<div class="large-image-placeholder">/)
+    end
   end
 
   context ".post_process_oneboxes removes nofollow if add_rel_nofollow_to_user_content is disabled" do