Fix Error 500s when viewing user or group Atom feeds

app/models/event.rb

@@ -83,6 +83,10 @@ class Event < ActiveRecord::Base
   self.inheritance_column = 'action'
 
   class << self
+    def model_name
+      ActiveModel::Name.new(self, nil, 'event')
+    end
+
     def find_sti_class(action)
       if action.to_i == PUSHED
         PushEvent
@@ -438,6 +442,12 @@ class Event < ActiveRecord::Base
     EventForMigration.create!(new_attributes)
   end
 
+  def to_partial_path
+    # We are intentionally using `Event` rather than `self.class` so that
+    # subclasses also use the `Event` implementation.
+    Event._to_partial_path
+  end
+
   private
 
   def recent_update?

spec/features/atom/users_spec.rb

@@ -41,6 +41,8 @@ describe "User Feed"  do
                target_project: project,
                description: "Here is the fix: ![an image](image.png)")
       end
+      let(:push_event) { create(:push_event, project: project, author: user) }
+      let!(:push_event_payload) { create(:push_event_payload, event: push_event) }
 
       before do
         project.team << [user, :master]
@@ -70,6 +72,10 @@ describe "User Feed"  do
       it 'has XHTML summaries in merge request descriptions' do
         expect(body).to match /Here is the fix: <a[^>]*><img[^>]*\/><\/a>/
       end
+
+      it 'has push event commit ID' do
+        expect(body).to have_content(Commit.truncate_sha(push_event.commit_id))
+      end
     end
   end