Toggling a task in a description with mentions doesn't creates a Todo

app/services/todo_service.rb

@@ -20,7 +20,7 @@ class TodoService
   #  * mark all pending todos related to the issue for the current user as done
   #
   def update_issue(issue, current_user)
-    create_mention_todos(issue.project, issue, current_user)
+    update_issuable(issue, current_user)
   end
 
   # When close an issue we should:
@@ -53,7 +53,7 @@ class TodoService
   #  * create a todo for each mentioned user on merge request
   #
   def update_merge_request(merge_request, current_user)
-    create_mention_todos(merge_request.project, merge_request, current_user)
+    update_issuable(merge_request, current_user)
   end
 
   # When close a merge request we should:
@@ -153,6 +153,13 @@ class TodoService
     create_mention_todos(issuable.project, issuable, author)
   end
 
+  def update_issuable(issuable, author)
+    # Skip toggling a task list item in a description
+    return if issuable.tasks? && issuable.updated_tasks.any?
+
+    create_mention_todos(issuable.project, issuable, author)
+  end
+
   def handle_note(note, author)
     # Skip system notes, and notes on project snippet
     return if note.system? || note.for_snippet?

spec/services/todo_service_spec.rb

@@ -18,7 +18,7 @@ describe TodoService, services: true do
   end
 
   describe 'Issues' do
-    let(:issue) { create(:issue, project: project, assignee: john_doe, author: author, description: mentions) }
+    let(:issue) { create(:issue, project: project, assignee: john_doe, author: author, description: "- [ ] Task 1\n- [ ] Task 2 #{mentions}") }
     let(:unassigned_issue) { create(:issue, project: project, assignee: nil) }
     let(:confidential_issue) { create(:issue, :confidential, project: project, author: author, assignee: assignee, description: mentions) }
 
@@ -101,6 +101,19 @@ describe TodoService, services: true do
         should_create_todo(user: admin, target: confidential_issue, author: john_doe, action: Todo::MENTIONED)
         should_not_create_todo(user: john_doe, target: confidential_issue, author: john_doe, action: Todo::MENTIONED)
       end
+
+      it 'does not create todo when when tasks are marked as completed' do
+        issue.update(description: "- [x] Task 1\n- [X] Task 2 #{mentions}")
+
+        service.update_issue(issue, author)
+
+        should_not_create_todo(user: admin, target: issue, action: Todo::MENTIONED)
+        should_not_create_todo(user: assignee, target: issue, action: Todo::MENTIONED)
+        should_not_create_todo(user: author, target: issue, action: Todo::MENTIONED)
+        should_not_create_todo(user: john_doe, target: issue, action: Todo::MENTIONED)
+        should_not_create_todo(user: member, target: issue, action: Todo::MENTIONED)
+        should_not_create_todo(user: non_member, target: issue, action: Todo::MENTIONED)
+      end
     end
 
     describe '#close_issue' do
@@ -210,7 +223,7 @@ describe TodoService, services: true do
   end
 
   describe 'Merge Requests' do
-    let(:mr_assigned) { create(:merge_request, source_project: project, author: author, assignee: john_doe, description: mentions) }
+    let(:mr_assigned) { create(:merge_request, source_project: project, author: author, assignee: john_doe, description: "- [ ] Task 1\n- [ ] Task 2 #{mentions}") }
     let(:mr_unassigned) { create(:merge_request, source_project: project, author: author, assignee: nil) }
 
     describe '#new_merge_request' do
@@ -253,6 +266,19 @@ describe TodoService, services: true do
 
         expect { service.update_merge_request(mr_assigned, author) }.not_to change(member.todos, :count)
       end
+
+      it 'does not create todo when when tasks are marked as completed' do
+        mr_assigned.update(description: "- [x] Task 1\n- [X] Task 2 #{mentions}")
+
+        service.update_merge_request(mr_assigned, author)
+
+        should_not_create_todo(user: admin, target: mr_assigned, action: Todo::MENTIONED)
+        should_not_create_todo(user: assignee, target: mr_assigned, action: Todo::MENTIONED)
+        should_not_create_todo(user: author, target: mr_assigned, action: Todo::MENTIONED)
+        should_not_create_todo(user: john_doe, target: mr_assigned, action: Todo::MENTIONED)
+        should_not_create_todo(user: member, target: mr_assigned, action: Todo::MENTIONED)
+        should_not_create_todo(user: non_member, target: mr_assigned, action: Todo::MENTIONED)
+      end
     end
 
     describe '#close_merge_request' do