Mark pending tasks for the current user as done when he edit a note

app/services/notes/update_service.rb

@@ -7,6 +7,10 @@ module Notes
       note.create_new_cross_references!(current_user)
       note.reset_events_cache
+      if note.previous_changes.include?('note')
+        TaskService.new.update_note(note, current_user)
+      end
+
       note
     end
   end

app/services/task_service.rb

@@ -54,6 +54,17 @@ class TaskService
     end
   end
+  # When update a note we should:
+  #
+  #  * mark all pending tasks related to the noteable for the current user as done
+  #
+  def update_note(note, current_user)
+    # Skip system notes, like status changes and cross-references
+    unless note.system
+      mark_as_done(note.noteable, current_user)
+    end
+  end
+
   private
   def create_task(project, target, author, user, action)

spec/services/notes/update_service_spec.rb

+require 'spec_helper'
+
+describe Notes::UpdateService, services: true do
+  let(:project) { create(:empty_project) }
+  let(:user) { create(:user) }
+  let(:user2) { create(:user) }
+  let(:issue) { create(:issue, project: project) }
+  let(:note) { create(:note, project: project, noteable: issue, author: user, note: 'Old note') }
+
+  before do
+    project.team << [user, :master]
+    project.team << [user2, :developer]
+  end
+
+  describe '#execute' do
+    def update_note(opts)
+      @note = Notes::UpdateService.new(project, user, opts).execute(note)
+      @note.reload
+    end
+
+    context 'task queue' do
+      let!(:task) { create(:pending_assigned_task, user: user, project: project, target: issue, author: user2) }
+
+      context 'when the note change' do
+        before do
+          update_note({ note: 'New note' })
+        end
+
+        it 'marks pending tasks as done' do
+          expect(task.reload).to be_done
+        end
+      end
+
+      context 'when the note does not change' do
+        before do
+          update_note({ note: 'Old note' })
+        end
+
+        it 'keep pending tasks' do
+          expect(task.reload).to be_pending
+        end
+      end
+    end
+  end
+end