diff options
Diffstat (limited to 'guides/source/upgrading_ruby_on_rails.md')
| -rw-r--r-- | guides/source/upgrading_ruby_on_rails.md | 70 |
1 files changed, 44 insertions, 26 deletions
diff --git a/guides/source/upgrading_ruby_on_rails.md b/guides/source/upgrading_ruby_on_rails.md index b8a5c39f39..f17955e022 100644 --- a/guides/source/upgrading_ruby_on_rails.md +++ b/guides/source/upgrading_ruby_on_rails.md @@ -134,6 +134,28 @@ Action Cable JavaScript API: + ActionCable.logger.enabled = false ``` +### `ActionDispatch::Response#content_type` now returns the Content-Type header without modification + +Previously, the return value of `ActionDispatch::Response#content_type` did NOT contain the charset part. +This behavior has changed to include the previously omitted charset part as well. + +If you want just the MIME type, please use `ActionDispatch::Response#media_type` instead. + +Before: + +```ruby +resp = ActionDispatch::Response.new(200, "Content-Type" => "text/csv; header=present; charset=utf-16") +resp.content_type #=> "text/csv; header=present" +``` + +After: + +```ruby +resp = ActionDispatch::Response.new(200, "Content-Type" => "text/csv; header=present; charset=utf-16") +resp.content_type #=> "text/csv; header=present; charset=utf-16" +resp.media_type #=> "text/csv" +``` + ### Autoloading The default configuration for Rails 6 @@ -162,41 +184,21 @@ That may be handy if you need to preload STIs or configure a custom inflector, f If the application being upgraded autoloads correctly, the project structure should be already mostly compatible. -However, `classic` mode infers file names from missing constant names (`underscore`), whereas `zeitwerk` mode infers constant names from file names (`camelize`). These helpers are not always inverse of each other, in particular if acronyms are involved. For instance, `"FOO".underscore` is `"foo"`, but `"foo".camelize` is `"Foo"`, not `"FOO"`. Compatibility can be checked by setting `classic` mode first temporarily: - -```ruby -# config/application.rb - -config.load_defaults "6.0" -config.autoloader = :classic -``` +However, `classic` mode infers file names from missing constant names (`underscore`), whereas `zeitwerk` mode infers constant names from file names (`camelize`). These helpers are not always inverse of each other, in particular if acronyms are involved. For instance, `"FOO".underscore` is `"foo"`, but `"foo".camelize` is `"Foo"`, not `"FOO"`. -and then running +Compatibility can be checked with the `zeitwerk:check` task: ``` -bin/rails zeitwerk:check +$ bin/rails zeitwerk:check +Hold on, I am eager loading the application. +All is good! ``` -When all is good, you can delete `config.autoloader = :classic`. - #### require_dependency All known use cases of `require_dependency` have been eliminated, you should grep the project and delete them. -In the case of STIs with a hierarchy of more than two levels, you can preload the leaves of the hierarchy in an initializer: - -```ruby -# config/initializers/preload_stis.rb - -# By preloading leaves, the hierarchy is loaded upwards following -# the references to superclasses in the class definitions. -sti_leaves = %w( - app/models/leaf1.rb - app/models/leaf2.rb - app/models/leaf3.rb -) -Rails.autoloaders.main.preload(sti_leaves) -``` +If your application has STIs, please check their section in the guide [Autoloading and Reloading Constants (Zeitwerk Mode)](autoloading_and_reloading_constants.html#single-table-inheritance). #### Qualified names in class and module definitions @@ -248,6 +250,16 @@ In that case, `app/models/concerns` is assumed to be a root directory (because i The `Concerns::` namespace worked with the classic autoloader as a side-effect of the implementation, but it was not really an intended behavior. An application using `Concerns::` needs to rename those classes and modules to be able to run in `zeitwerk` mode. +#### Having `app` in the autoload paths + +Some projects want something like `app/api/base.rb` to define `API::Base`, and add `app` to the autoload paths to accomplish that in `classic` mode. Since Rails adds all subdirectories of `app` to the autoload paths automatically, we have another situation in which there are nested root directories, so that setup no longer works. Similar principle we explained above with `concerns`. + +If you want to keep that structure, you'll need to delete the subdirectory from the autoload paths in an initializer: + +```ruby +ActiveSupport::Dependencies.autoload_paths.delete("#{Rails.root}/app/api") +``` + #### Autoloaded Constants and Explicit Namespaces If a namespace is defined in a file, as `Hotel` is here: @@ -369,6 +381,12 @@ To fix this, just remove the wildcards: config.autoload_paths << "#{config.root}/lib" ``` +#### Eager loading and autoloading are consistent + +In `classic` mode, if `app/models/foo.rb` defines `Bar`, you won't be able to autoload that file, but eager loading will work because it loads files recursively blindly. This can be a source of errors if you test things first eager loading, execution may fail later autoloading. + +In `zeitwerk` mode both loading modes are consistent, they fail and err in the same files. + #### How to Use the Classic Autoloader in Rails 6 Applications can load Rails 6 defaults and still use the classic autoloader by setting `config.autoloader` this way: |