{"id":78,"hash":"1aa83f3f3501545cb050c241638278aeb144b1b117459a59c4c88a2d4b325bd4","pattern":"NameError: uninitialized constant","full_message":"NameError: uninitialized constant User","ecosystem":"rubygems","package_name":"rails","package_version":null,"solution":"Rails autoloading (Zeitwerk) couldn't find a constant.\n1. File naming: `User` must live in `app/models/user.rb`. Nested: `Admin::User` -> `app/models/admin/user.rb`.\n2. Run `bin/rails zeitwerk:check` — it prints exactly which file-constant mapping is wrong.\n3. After adding a file, restart the dev server if eager_loading is off.","confidence":0.92,"source":"rails-docs","source_url":"https://guides.rubyonrails.org/autoloading_and_reloading_constants.html","votes":24,"created_at":"2026-04-19T03:37:14.149745+00:00","updated_at":"2026-04-19T03:37:14.149745+00:00"}