Add a note when an Issue or Merge Request's title changes

4 files changed, 32 insertions, 0 deletions

diff --git a/app/services/issuable_base_service.rb b/app/services/issuable_base_service.rb
index 8960235b093..c5769a5ad27 100644
--- a/app/services/issuable_base_service.rb
+++ b/app/services/issuable_base_service.rb
@@ -15,4 +15,9 @@ class IssuableBaseService < BaseService
     SystemNoteService.change_label(
       issuable, issuable.project, current_user, added_labels, removed_labels)
   end
+
+  def create_title_change_note(issuable, old_title)
+    SystemNoteService.change_title(
+      issuable, issuable.project, current_user, old_title)
+  end
 end
diff --git a/app/services/issues/update_service.rb b/app/services/issues/update_service.rb
index 8f04a69287a..6af942a5ca4 100644
--- a/app/services/issues/update_service.rb
+++ b/app/services/issues/update_service.rb
@@ -37,6 +37,10 @@ module Issues
           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
+
         issue.notice_added_references(issue.project, current_user)
         execute_hooks(issue, 'update')
       end
diff --git a/app/services/merge_requests/update_service.rb b/app/services/merge_requests/update_service.rb
index 23af2656c37..34fd59d6927 100644
--- a/app/services/merge_requests/update_service.rb
+++ b/app/services/merge_requests/update_service.rb
@@ -50,6 +50,10 @@ 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
+
         merge_request.notice_added_references(merge_request.project, current_user)
         execute_hooks(merge_request, 'update')
       end
diff --git a/app/services/system_note_service.rb b/app/services/system_note_service.rb
index 0614f8689a4..1909ae0d6f1 100644
--- a/app/services/system_note_service.rb
+++ b/app/services/system_note_service.rb
@@ -130,6 +130,25 @@ class SystemNoteService
     create_note(noteable: noteable, project: project, author: author, note: body)
   end
 
+  # Called when the title of a Noteable is changed
+  #
+  # noteable  - Noteable object that responds to `title`
+  # project   - Project owning noteable
+  # author    - User performing the change
+  # old_title - Previous String title
+  #
+  # Example Note text:
+  #
+  #   "Title changed from **Old** to **New**"
+  #
+  # Returns the created Note object
+  def self.change_title(noteable, project, author, old_title)
+    return unless noteable.respond_to?(:title)
+
+    body = "Title changed from **#{old_title}** to **#{noteable.title}**"
+    create_note(noteable: noteable, project: project, author: author, note: body)
+  end
+
   # Called when a Mentionable references a Noteable
   #
   # noteable  - Noteable object being referenced