Merge branch 'fix-issue-2382' into 'master'

Create a "destroyed Milestone" event and keep Milestone events around in the DB for posterity

Also fix issue where destroying a Milestone would cause odd, transient messages like "created milestone" or "imported milestone".

Now if a milestone is destroyed, at least it will indicate in the activity feed even if it's not clear which milestone was destroyed:

![image](https://gitlab.com/gitlab-org/gitlab-ce/uploads/c89cc8a0a9fa549deac433f17b890913/image.png)

Closes #2382

See merge request !1227

2 files changed, 26 insertions, 0 deletions

diff --git a/app/services/event_create_service.rb b/app/services/event_create_service.rb
index 103d6b0a08b..07fc77001a5 100644
--- a/app/services/event_create_service.rb
+++ b/app/services/event_create_service.rb
@@ -46,6 +46,10 @@ class EventCreateService
     create_record_event(milestone, current_user, Event::REOPENED)
   end
 
+  def destroy_milestone(milestone, current_user)
+    create_record_event(milestone, current_user, Event::DESTROYED)
+  end
+
   def leave_note(note, current_user)
     create_record_event(note, current_user, Event::COMMENTED)
   end
diff --git a/app/services/milestones/destroy_service.rb b/app/services/milestones/destroy_service.rb
new file mode 100644
index 00000000000..7ce7d259d0b
--- /dev/null
+++ b/app/services/milestones/destroy_service.rb
@@ -0,0 +1,22 @@
+module Milestones
+  class DestroyService < Milestones::BaseService
+    def execute(milestone)
+
+      Milestone.transaction do
+        update_params = { milestone: nil }
+        milestone.issues.each do |issue|
+          Issues::UpdateService.new(project, current_user, update_params).execute(issue)
+        end
+
+        event_service.destroy_milestone(milestone, current_user)
+
+        Event.for_milestone_id(milestone.id).each do |event|
+          event.target_id = nil
+          event.save
+        end
+
+        milestone.destroy
+      end
+    end
+  end
+end