Ignore error if mentioned account was not processable (#29215)

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

spec/lib/activitypub/activity/create_spec.rb

@@ -63,6 +63,24 @@ RSpec.describe ActivityPub::Activity::Create do
       }
     end
 
+    let(:invalid_mention_json) do
+      {
+        id: [ActivityPub::TagManager.instance.uri_for(sender), 'post2'].join('/'),
+        type: 'Note',
+        to: [
+          'https://www.w3.org/ns/activitystreams#Public',
+          ActivityPub::TagManager.instance.uri_for(follower),
+        ],
+        content: '@bob lorem ipsum',
+        published: 1.hour.ago.utc.iso8601,
+        updated: 1.hour.ago.utc.iso8601,
+        tag: {
+          type: 'Mention',
+          href: 'http://notexisting.dontexistingtld/actor',
+        },
+      }
+    end
+
     def activity_for_object(json)
       {
         '@context': 'https://www.w3.org/ns/activitystreams',
@@ -117,6 +135,25 @@ RSpec.describe ActivityPub::Activity::Create do
       # Creates two notifications
       expect(Notification.count).to eq 2
     end
+
+    it 'ignores unprocessable mention', :aggregate_failures do
+      stub_request(:get, invalid_mention_json[:tag][:href]).to_raise(HTTP::ConnectionError)
+      # When receiving the post that contains an invalid mention…
+      described_class.new(activity_for_object(invalid_mention_json), sender, delivery: true).perform
+
+      # NOTE: Refering explicitly to the workers is a bit awkward
+      DistributionWorker.drain
+      FeedInsertWorker.drain
+
+      # …it creates a status
+      status = Status.find_by(uri: invalid_mention_json[:id])
+
+      # Check the process did not crash
+      expect(status.nil?).to be false
+
+      # It has queued a mention resolve job
+      expect(MentionResolveWorker).to have_enqueued_sidekiq_job(status.id, invalid_mention_json[:tag][:href], anything)
+    end
   end
 
   describe '#perform' do