Add system note with link to diff comparison when MR discussion becomes outdated

1 files changed, 23 insertions, 1 deletions

diff --git a/app/services/system_note_service.rb b/app/services/system_note_service.rb
index 93bf1fb1615..0837c07e6aa 100644
--- a/app/services/system_note_service.rb
+++ b/app/services/system_note_service.rb
@@ -258,7 +258,7 @@ module SystemNoteService
     create_note(NoteSummary.new(noteable, project, author, body, action: 'title'))
   end
 
-  def self.resolve_all_discussions(merge_request, project, author)
+  def resolve_all_discussions(merge_request, project, author)
     body = "resolved all discussions"
 
     create_note(NoteSummary.new(merge_request, project, author, body, action: 'discussion'))
@@ -274,6 +274,28 @@ module SystemNoteService
     note
   end
 
+  def diff_discussion_outdated(discussion, project, author, change_position)
+    merge_request = discussion.noteable
+    diff_refs = change_position.diff_refs
+    version_index = merge_request.merge_request_diffs.viewable.count
+
+    body = "changed this line in"
+    if version_params = merge_request.version_params_for(diff_refs)
+      line_code = change_position.line_code(project.repository)
+      url = url_helpers.diffs_namespace_project_merge_request_url(project.namespace, project, merge_request, version_params.merge(anchor: line_code))
+
+      body << " [version #{version_index} of the diff](#{url})"
+    else
+      body << " version #{version_index} of the diff"
+    end
+
+    note_attributes = discussion.reply_attributes.merge(project: project, author: author, note: body)
+    note = Note.create(note_attributes.merge(system: true))
+    note.system_note_metadata = SystemNoteMetadata.new(action: 'outdated')
+
+    note
+  end
+
   # Called when the title of a Noteable is changed
   #
   # noteable  - Noteable object that responds to `title`