Support Todos REST API returning Todos for Designs
Problem to solve
Todo API should return
Designs were intentionally excluded from being returned in the
Todo REST API after issues were discovered with returning them.
- See discussion https://gitlab.com/gitlab-org/gitlab-ee/issues/13494#note_203518559.
- The MR that excluded design Todos from the REST API https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/15129.
The feature should be able to be toggled off with a feature flag.
Permissions and Security
Todos should avoid n+1 issues when returned from the REST API.