Generate system note after Task item has been updated on Issue or Merge Request. #2296

Everytime the User check or uncheck a Task Item from the Issue or
Merge Request description, a new update is going to be
added to the activity logs of the Issue or Merge Request.

Note that when using the edit form, you can only update the Task item
status or add/delete/modify existing ones. Doing both actions is not
fully supported.

4 files changed, 34 insertions, 8 deletions

diff --git a/app/services/issuable_base_service.rb b/app/services/issuable_base_service.rb
index 11d2b08bba7..19055fb67ff 100644
--- a/app/services/issuable_base_service.rb
+++ b/app/services/issuable_base_service.rb
@@ -27,6 +27,12 @@ class IssuableBaseService < BaseService
       old_branch, new_branch)
   end
 
+  def create_task_status_note(issuable)
+    issuable.updated_tasks.each do |task|
+      SystemNoteService.change_task_status(issuable, issuable.project, current_user, task)
+    end
+  end
+
   def filter_params(issuable_ability_name = :issue)
     params[:assignee_id]  = "" if params[:assignee_id] == IssuableFinder::NONE
     params[:milestone_id] = "" if params[:milestone_id] == IssuableFinder::NONE
@@ -55,6 +61,7 @@ class IssuableBaseService < BaseService
           old_labels - issuable.labels)
       end
 
+      handle_common_system_notes(issuable)
       handle_changes(issuable)
       issuable.create_new_cross_references!(current_user)
       execute_hooks(issuable, 'update')
@@ -71,4 +78,14 @@ class IssuableBaseService < BaseService
       close_service.new(project, current_user, {}).execute(issuable)
     end
   end
+
+  def handle_common_system_notes(issuable)
+    if issuable.previous_changes.include?('title')
+      create_title_change_note(issuable, issuable.previous_changes['title'].first)
+    end
+
+    if issuable.previous_changes.include?('description') && issuable.tasks?
+      create_task_status_note(issuable)
+    end
+  end
 end
diff --git a/app/services/issues/update_service.rb b/app/services/issues/update_service.rb
index 7c112f731a7..a55a04dd5e0 100644
--- a/app/services/issues/update_service.rb
+++ b/app/services/issues/update_service.rb
@@ -13,10 +13,6 @@ module Issues
         create_assignee_note(issue)
         notification_service.reassigned_issue(issue, current_user)
       end
-
-      if issue.previous_changes.include?('title')
-        create_title_change_note(issue, issue.previous_changes['title'].first)
-      end
     end
 
     def reopen_service
diff --git a/app/services/merge_requests/update_service.rb b/app/services/merge_requests/update_service.rb
index a5db3776eb6..5ff2cc03dda 100644
--- a/app/services/merge_requests/update_service.rb
+++ b/app/services/merge_requests/update_service.rb
@@ -30,10 +30,6 @@ module MergeRequests
         notification_service.reassigned_merge_request(merge_request, current_user)
       end
 
-      if merge_request.previous_changes.include?('title')
-        create_title_change_note(merge_request, merge_request.previous_changes['title'].first)
-      end
-
       if merge_request.previous_changes.include?('target_branch') ||
           merge_request.previous_changes.include?('source_branch')
         merge_request.mark_as_unchecked
diff --git a/app/services/system_note_service.rb b/app/services/system_note_service.rb
index 708c2f00486..7c5d523ef39 100644
--- a/app/services/system_note_service.rb
+++ b/app/services/system_note_service.rb
@@ -341,4 +341,21 @@ class SystemNoteService
 
     "* #{commit_ids} - #{commits_text} from branch `#{branch}`\n"
   end
+
+  # Called when the status of a Task has changed
+  #
+  # noteable  - Noteable object.
+  # project   - Project owning noteable
+  # author    - User performing the change
+  # new_task  - TaskList::Item object.
+  #
+  # Example Note text:
+  #
+  #   "Soandso marked the task Whatever as completed."
+  #
+  # Returns the created Note object
+  def self.change_task_status(noteable, project, author, new_task)
+    body = "Marked the task **#{new_task.source}** as #{new_task.status_label}"
+    create_note(noteable: noteable, project: project, author: author, note: body)
+  end
 end