Handle incorrect content IDs found in embeds

Previously, an uncaught error was raised in a
content block's content ID couldn't be found,
which prevented any editions being published if
they had an incorrect embed code within them, with
no feedback for the user on Mainstream when this
happened.

This is change sends an exception to Sentry to
alert developers the event has occurred, and
does not add the incorrect ID to the Links on a
Document, which will prevent the embed code
causing more problems when the editions is
published and going through the rendering process
via the `ContentEmbedPresenter`.

The user should be able to see their changes
published, and the embed code will appear as plain
text on the frontend, so it should be easy to spot
and change.

app/services/embedded_content_finder_service.rb

@@ -4,8 +4,7 @@ def fetch_linked_content_ids(details, locale)
       find_content_references(value)
     }.flatten.compact
 
-    check_all_references_exist(content_references.uniq, locale)
-    content_references.map(&:content_id)
+    live_content_ids(content_references, locale)
   end
 
   def find_content_references(value)
@@ -23,16 +22,17 @@ def find_content_references(value)
 
 private
 
-  def check_all_references_exist(content_references, locale)
-    found_editions = live_editions(content_references, locale)
+  def live_content_ids(content_references, locale)
+    found_editions = live_editions(content_references.uniq, locale)
     not_found_content_ids = content_references.map(&:content_id) - found_editions.map(&:content_id)
 
     if not_found_content_ids.any?
-      raise CommandError.new(
-        code: 422,
-        message: "Could not find any live editions in locale #{locale} for: #{not_found_content_ids.join(', ')}, ",
-      )
+      Sentry.capture_exception(CommandError.new(
+                                 code: 422,
+                                 message: "Could not find any live content blocks for content IDs: #{not_found_content_ids.join(', ')}",
+                               ))
     end
+    content_references.map(&:content_id) - not_found_content_ids
   end
 
   def live_editions(content_references, locale)

spec/services/embedded_content_finder_service_spec.rb

@@ -179,16 +179,20 @@
         expect(links).to eq([editions[0].content_id, editions[0].content_id, editions[1].content_id])
       end
 
-      it "errors when given a content ID that is still draft" do
+      it "does not return a content ID that is still draft" do
         details = { field_name => "{{embed:#{document_type}:#{draft_edition.content_id}}}" }
 
-        expect { EmbeddedContentFinderService.new.fetch_linked_content_ids(details, Edition::DEFAULT_LOCALE) }.to raise_error(CommandError)
+        links = EmbeddedContentFinderService.new.fetch_linked_content_ids(details, "foo")
+
+        expect(links).to eq([])
       end
 
-      it "errors when given a live content ID that is not available in the current locale" do
+      it "does not return a live content ID that is not available in the current locale" do
         details = { field_name => "{{embed:#{document_type}:#{editions[0].content_id}}}" }
 
-        expect { EmbeddedContentFinderService.new.fetch_linked_content_ids(details, "foo") }.to raise_error(CommandError)
+        links = EmbeddedContentFinderService.new.fetch_linked_content_ids(details, "foo")
+
+        expect(links).to eq([])
       end
     end
   end
@@ -208,10 +212,16 @@
       expect(links).to eq([])
     end
 
-    it "errors when given a content ID that has no live editions" do
+    it "alerts Sentry when there is are embeds without live editions" do
       details = { body: "{{embed:contact:00000000-0000-0000-0000-000000000000}}" }
+      expect(Sentry).to receive(:capture_exception).with(CommandError.new(
+                                                           code: 422,
+                                                           message: "Could not find any live content blocks for content IDs: 00000000-0000-0000-0000-000000000000",
+                                                         ))
 
-      expect { EmbeddedContentFinderService.new.fetch_linked_content_ids(details, Edition::DEFAULT_LOCALE) }.to raise_error(CommandError)
+      links = EmbeddedContentFinderService.new.fetch_linked_content_ids(details, "foo")
+
+      expect(links).to eq([])
     end
 
     context "when the field value is an array" do