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| -rw-r--r-- | guides/source/upgrading_ruby_on_rails.md | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/guides/source/upgrading_ruby_on_rails.md b/guides/source/upgrading_ruby_on_rails.md index 4192063e9b..123f8dce80 100644 --- a/guides/source/upgrading_ruby_on_rails.md +++ b/guides/source/upgrading_ruby_on_rails.md @@ -201,6 +201,29 @@ bin/rails zeitwerk:check When all is good, you can delete `config.autoloader = :classic`. +That checker may technically be fooled in some rare cases, but it works well in practice for projects that are running correctly in a previous versions of Rails and are being upgraded. This task tries to print a helpful report. + +If that check is good, we recommend to do a second one, more strict: Eager load the application in `zeitwerk` mode. In order to do that, enable eager loading in `development` mode: + +```ruby +# config/initializers/development.rb +config.eager_load = true +``` + +and boot the application: + +```ruby +bin/rails runner 1 +``` + +If a file does not match the constant it defines, you'll get a raw `NameError` explaining the discrepancy: + +``` +expected file ... to define constant ..., but didn't (NameError) +``` + +Once all is good, you'll just get a prompt back. Remember to disable `config.eager_load`, it it was false before. + #### require_dependency All known use cases of `require_dependency` have been eliminated, you should grep the project and delete them. |