diff options
Diffstat (limited to 'guides/source')
| -rw-r--r-- | guides/source/6_0_release_notes.md | 245 | ||||
| -rw-r--r-- | guides/source/action_text_overview.md | 2 | ||||
| -rw-r--r-- | guides/source/active_record_migrations.md | 2 | ||||
| -rw-r--r-- | guides/source/active_support_instrumentation.md | 11 | ||||
| -rw-r--r-- | guides/source/configuring.md | 2 | ||||
| -rw-r--r-- | guides/source/contributing_to_ruby_on_rails.md | 2 | ||||
| -rw-r--r-- | guides/source/testing.md | 2 | ||||
| -rw-r--r-- | guides/source/upgrading_ruby_on_rails.md | 219 |
8 files changed, 459 insertions, 26 deletions
diff --git a/guides/source/6_0_release_notes.md b/guides/source/6_0_release_notes.md index 17d1132e73..1b37bf50e1 100644 --- a/guides/source/6_0_release_notes.md +++ b/guides/source/6_0_release_notes.md @@ -151,25 +151,44 @@ Please refer to the [Changelog][action-cable] for detailed changes. ### Removals +* Replace `ActionCable.startDebugging()` and `ActionCable.stopDebugging()` + with `ActionCable.logger.enabled`. + ([Pull Request](https://github.com/rails/rails/pull/34370)) + ### Deprecations +* There are no deprecations for Action Cable in Rails 6.0. + ### Notable changes -* The ActionCable javascript package has been converted from CoffeeScript - to ES2015, and we now publish the source code in the npm distribution. +* Add support for the `channel_prefix` option for PostgreSQL subscription adapters + in `cable.yml`. + ([Pull Request](https://github.com/rails/rails/pull/35276)) + +* Allow passing a custom configuration to `ActionCable::Server::Base`. + ([Pull Request](https://github.com/rails/rails/pull/34714)) + +* Add `:action_cable_connection` and `:action_cable_channel` load hooks. + ([Pull Request](https://github.com/rails/rails/pull/35094)) - This allows ActionCable users to depend on the javascript source code - rather than the compiled code, which can produce smaller javascript bundles. +* Add `Channel::Base#broadcast_to` and `Channel::Base.broadcasting_for`. + ([Pull Request](https://github.com/rails/rails/pull/35021)) - This change includes some breaking changes to optional parts of the - ActionCable javascript API: +* Close a connection when calling `reject_unauthorized_connection` from an + `ActionCable::Connection`. + ([Pull Request](https://github.com/rails/rails/pull/34194)) - - Configuration of the WebSocket adapter and logger adapter have been moved - from properties of `ActionCable` to properties of `ActionCable.adapters`. +* Convert the Action Cable JavaScript package from CoffeeScript to ES2015 and + publish the source code in the npm distribution. + ([Pull Request](https://github.com/rails/rails/pull/34370)) - - The `ActionCable.startDebugging()` and `ActionCable.stopDebugging()` - methods have been removed and replaced with the property - `ActionCable.logger.enabled`. +* Move the configuration of the WebSocket adapter and logger adapter + from properties of `ActionCable` to `ActionCable.adapters`. + ([Pull Request](https://github.com/rails/rails/pull/34370)) + +* Add an `id` option to the Redis adapter to distinguish Action Cable's Redis + connections. + ([Pull Request](https://github.com/rails/rails/pull/33798)) Action Pack ----------- @@ -183,7 +202,7 @@ Please refer to the [Changelog][action-pack] for detailed changes. * Remove deprecated methods in `ActionDispatch::TestResponse`: `#success?` in favor of `#successful?`, `#missing?` in favor of `#not_found?`, - `#error?` in favor of `#server_error?` + `#error?` in favor of `#server_error?`. ([Commit](https://github.com/rails/rails/commit/13ddc92e079e59a0b894e31bf5bb4fdecbd235d1)) ### Deprecations @@ -210,7 +229,7 @@ Please refer to the [Changelog][action-pack] for detailed changes. * Allow the use of `parsed_body` in `ActionController::TestCase`. ([Pull Request](https://github.com/rails/rails/pull/34717)) -* Raise an `ArgumentError` when multiple root routes exists in the same context +* Raise an `ArgumentError` when multiple root routes exist in the same context without `as:` naming specifications. ([Pull Request](https://github.com/rails/rails/pull/34494)) @@ -279,14 +298,14 @@ Please refer to the [Changelog][action-view] for detailed changes. ### Notable changes -* Clear ActionView cache in development only on file changes, speeding up +* Clear Action View cache in development only on file changes, speeding up development mode. ([Pull Request](https://github.com/rails/rails/pull/35629)) * Move all of the Rails npm packages into a `@rails` scope. ([Pull Request](https://github.com/rails/rails/pull/34905)) -* Only accept formats from registered Mime types. +* Only accept formats from registered MIME types. ([Pull Request](https://github.com/rails/rails/pull/35604), [Pull Request](https://github.com/rails/rails/pull/35753)) * Add allocations to the template and partial rendering server output. @@ -304,7 +323,7 @@ Please refer to the [Changelog][action-view] for detailed changes. enable `ActionView::Template` finalizers. ([Pull Request](https://github.com/rails/rails/pull/32418)) -* Extract the JS `confirm` call to its own, overridable method in `rails_ujs`. +* Extract the JavaScript `confirm` call to its own, overridable method in `rails_ujs`. ([Pull Request](https://github.com/rails/rails/pull/32404)) * Add a `action_controller.default_enforce_utf8` configuration option to handle @@ -383,7 +402,7 @@ Please refer to the [Changelog][active-record] for detailed changes. * Remove support for passing the column name to `count` when a block is passed. ([Commit](https://github.com/rails/rails/commit/67356f2034ab41305af7218f7c8b2fee2d614129)) -* Remove support for delegation of missing methods in a relation to arel. +* Remove support for delegation of missing methods in a relation to Arel. ([Commit](https://github.com/rails/rails/commit/d97980a16d76ad190042b4d8578109714e9c53d0)) * Remove support for delegating missing methods in a relation to private methods of the class. @@ -426,7 +445,7 @@ Please refer to the [Changelog][active-record] for detailed changes. ### Notable changes -* Bump the minimum sqlite3 version to 1.4. +* Bump the minimum version of the `sqlite3` gem to 1.4. ([Pull Request](https://github.com/rails/rails/pull/35844)) * Add `rails db:prepare` to create a database if it doesn't exist, and run its migrations. @@ -448,7 +467,7 @@ Please refer to the [Changelog][active-record] for detailed changes. ([Pull Request](https://github.com/rails/rails/pull/35631)) * Add `rails db:seed:replant` that truncates tables of each database - for ther current environment and loads the seeds. + for the current environment and loads the seeds. ([Pull Request](https://github.com/rails/rails/pull/34779)) * Add `reselect` method, which is a short-hand for `unscope(:select).select(fields)`. @@ -558,7 +577,7 @@ Please refer to the [Changelog][active-record] for detailed changes. * Allow the `:to_table` option of `remove_foreign_key` to be invertible. ([Pull Request](https://github.com/rails/rails/pull/33530)) -* Fix default value for mysql time types with specified precision. +* Fix default value for MySQL time types with specified precision. ([Pull Request](https://github.com/rails/rails/pull/33280)) * Fix the `touch` option to behave consistently with `Persistence#touch` method. @@ -723,10 +742,196 @@ Please refer to the [Changelog][active-support] for detailed changes. ### Removals +* Remove deprecated `#acronym_regex` method from `Inflections`. + ([Commit](https://github.com/rails/rails/commit/0ce67d3cd6d1b7b9576b07fecae3dd5b422a5689)) + +* Remove deprecated `Module#reachable?` method. + ([Commit](https://github.com/rails/rails/commit/6eb1d56a333fd2015610d31793ed6281acd66551)) + +* Remove `` Kernel#` `` without any replacement. + ([Pull Request](https://github.com/rails/rails/pull/31253)) + ### Deprecations +* Deprecate using negative integer arguments for `String#first` and + `String#last`. + ([Pull Request](https://github.com/rails/rails/pull/33058)) + +* Deprecate `ActiveSupport::Multibyte::Unicode#downcase/upcase/swapcase` + in favor of `String#downcase/upcase/swapcase`. + ([Pull Request](https://github.com/rails/rails/pull/34123)) + +* Deprecate `ActiveSupport::Multibyte::Unicode#normalize` + and `ActiveSupport::Multibyte::Chars#normalize` in favor of + `String#unicode_normalize`. + ([Pull Request](https://github.com/rails/rails/pull/34202)) + +* Deprecate `ActiveSupport::Multibyte::Chars.consumes?` in favor of + `String#is_utf8?`. + ([Pull Request](https://github.com/rails/rails/pull/34215)) + +* Deprecate `ActiveSupport::Multibyte::Unicode#pack_graphemes(array)` + and `ActiveSupport::Multibyte::Unicode#unpack_graphemes(string)` + in favor of `array.flatten.pack("U*")` and `string.scan(/\X/).map(&:codepoints)`, + respectively. + ([Pull Request](https://github.com/rails/rails/pull/34254)) + ### Notable changes +* Add support for parallel testing. + ([Pull Request](https://github.com/rails/rails/pull/31900)) + +* Make sure that `String#strip_heredoc` preserves frozen-ness of strings. + ([Pull Request](https://github.com/rails/rails/pull/32037)) + +* Add `String#truncate_bytes` to truncate a string to a maximum bytesize + without breaking multibyte characters or grapheme clusters. + ([Pull Request](https://github.com/rails/rails/pull/27319)) + +* Add `private` option to `delegate` method in order to delegate to + private methods. This option accepts `true/false` as the value. + ([Pull Request](https://github.com/rails/rails/pull/31944)) + +* Add support for translations through I18n for `ActiveSupport::Inflector#ordinal` + and `ActiveSupport::Inflector#ordinalize`. + ([Pull Request](https://github.com/rails/rails/pull/32168)) + +* Add `before?` and `after?` methods to `Date`, `DateTime`, + `Time`, and `TimeWithZone`. + ([Pull Request](https://github.com/rails/rails/pull/32185)) + +* Fix bug where `URI.unescape` would fail with mixed Unicode/escaped character + input. + ([Pull Request](https://github.com/rails/rails/pull/32183)) + +* Fix bug where `ActiveSupport::Cache` would massively inflate the storage + size when compression was enabled. + ([Pull Request](https://github.com/rails/rails/pull/32539)) + +* Redis cache store: `delete_matched` no longer blocks the Redis server. + ([Pull Request](https://github.com/rails/rails/pull/32614)) + +* Fix bug where `ActiveSupport::TimeZone.all` would fail when tzinfo data for + any timezone defined in `ActiveSupport::TimeZone::MAPPING` was missing. + ([Pull Request](https://github.com/rails/rails/pull/32613)) + +* Add `Enumerable#index_with` which allows creating a hash from an enumerable + with the value from a passed block or a default argument. + ([Pull Request](https://github.com/rails/rails/pull/32523)) + +* Allow `Range#===` and `Range#cover?` methods to work with `Range` argument. + ([Pull Request](https://github.com/rails/rails/pull/32938)) + +* Support key expiry in `increment/decrement` operations of RedisCacheStore. + ([Pull Request](https://github.com/rails/rails/pull/33254)) + +* Add cpu time, idle time, and allocations features to log subscriber events. + ([Pull Request](https://github.com/rails/rails/pull/33449)) + +* Add support for event object to the Active Support notification system. + ([Pull Request](https://github.com/rails/rails/pull/33451)) + +* Add support for not caching `nil` entries by introducing new option `skip_nil` + for `ActiveSupport::Cache#fetch`. + ([Pull Request](https://github.com/rails/rails/pull/25437)) + +* Add `Array#extract!` method which removes and returns the elements for which + block returns a true value. + ([Pull Request](https://github.com/rails/rails/pull/33137)) + +* Keep an HTML-safe string HTML-safe after slicing. + ([Pull Request](https://github.com/rails/rails/pull/33808)) + +* Add support for tracing constant autoloads via logging. + ([Commit](https://github.com/rails/rails/commit/c03bba4f1f03bad7dc034af555b7f2b329cf76f5)) + +* Define `unfreeze_time` as an alias of `travel_back`. + ([Pull Request](https://github.com/rails/rails/pull/33813)) + +* Change `ActiveSupport::TaggedLogging.new` to return a new logger instance + instead of mutating the one received as argument. + ([Pull Request](https://github.com/rails/rails/pull/27792)) + +* Treat `#delete_prefix`, `#delete_suffix` and `#unicode_normalize` methods + as non HTML-safe methods. + ([Pull Request](https://github.com/rails/rails/pull/33990)) + +* Fix bug where `#without` for `ActiveSupport::HashWithIndifferentAccess` + would fail with symbol arguments. + ([Pull Request](https://github.com/rails/rails/pull/34012)) + +* Rename `Module#parent`, `Module#parents`, and `Module#parent_name` to + `module_parent`, `module_parents`, and `module_parent_name`. + ([Pull Request](https://github.com/rails/rails/pull/34051)) + +* Add `ActiveSupport::ParameterFilter`. + ([Pull Request](https://github.com/rails/rails/pull/34039)) + +* Fix issue where duration was being rounded to a full second when a float + was added to the duration. + ([Pull Request](https://github.com/rails/rails/pull/34135)) + +* Make `#to_options` an alias for `#symbolize_keys` in + `ActiveSupport::HashWithIndifferentAccess`. + ([Pull Request](https://github.com/rails/rails/pull/34360)) + +* Don't raise an exception anymore if the same block is included multiple times + for a Concern. + ([Pull Request](https://github.com/rails/rails/pull/34553)) + +* Preserve key order passed to `ActiveSupport::CacheStore#fetch_multi`. + ([Pull Request](https://github.com/rails/rails/pull/34700)) + +* Fix `String#safe_constantize` to not throw a `LoadError` for incorrectly + cased constant references. + ([Pull Request](https://github.com/rails/rails/pull/34892)) + +* Add `Hash#deep_transform_values` and `Hash#deep_transform_values!`. + ([Commit](https://github.com/rails/rails/commit/b8dc06b8fdc16874160f61dcf58743fcc10e57db)) + +* Add `ActiveSupport::HashWithIndifferentAccess#assoc`. + ([Pull Request](https://github.com/rails/rails/pull/35080)) + +* Add `before_reset` callback to `CurrentAttributes` and define + `after_reset` as an alias of `resets` for symmetry. + ([Pull Request](https://github.com/rails/rails/pull/35063)) + +* Revise `ActiveSupport::Notifications.unsubscribe` to correctly + handle Regex or other multiple-pattern subscribers. + ([Pull Request](https://github.com/rails/rails/pull/32861)) + +* Add new autoloading mechanism using Zeitwerk. + ([Commit](https://github.com/rails/rails/commit/e53430fa9af239e21e11548499d814f540d421e5)) + +* Add `Array#including` and `Enumerable#including` to conveniently enlarge + a collection. + ([Commit](https://github.com/rails/rails/commit/bfaa3091c3c32b5980a614ef0f7b39cbf83f6db3)) + +* Rename `Array#without` and `Enumerable#without` to `Array#excluding` + and `Enumerable#excluding`. Old method names are retained as aliases. + ([Commit](https://github.com/rails/rails/commit/bfaa3091c3c32b5980a614ef0f7b39cbf83f6db3)) + +* Add support for supplying `locale` to `transliterate` and `parameterize`. + ([Pull Request](https://github.com/rails/rails/pull/35571)) + +* Fix `Time#advance` to work with dates before 1001-03-07. + ([Pull Request](https://github.com/rails/rails/pull/35659)) + +* Update `ActiveSupport::Notifications::Instrumenter#instrument` to allow + not passing block. + ([Pull Request](https://github.com/rails/rails/pull/35705)) + +* Use weak references in descendants tracker to allow anonymous subclasses to + be garbage collected. + ([Pull Request](https://github.com/rails/rails/pull/31442)) + +* Calling test methods with `with_info_handler` method to allow minitest-hooks + plugin to work. + ([Commit](https://github.com/rails/rails/commit/758ba117a008b6ea2d3b92c53b6a7a8d7ccbca69)) + +* Preserve `html_safe?` status on `ActiveSupport::SafeBuffer#*`. + ([Pull Request](https://github.com/rails/rails/pull/36012)) + Active Job ---------- diff --git a/guides/source/action_text_overview.md b/guides/source/action_text_overview.md index 08ec35e52a..07919775e2 100644 --- a/guides/source/action_text_overview.md +++ b/guides/source/action_text_overview.md @@ -91,7 +91,7 @@ end By default, the Action Text editor and content is styled by the Trix defaults. If you want to change these defaults, you'll want to remove -the `app/assets/stylesheets/actiontext.css` linker and base your stylings on +the `app/assets/stylesheets/actiontext.scss` linker and base your stylings on the [contents of that file](https://raw.githubusercontent.com/basecamp/trix/master/dist/trix.css). You can also style the HTML used for embedded images and other attachments (known as blobs). diff --git a/guides/source/active_record_migrations.md b/guides/source/active_record_migrations.md index 270e4a3bf9..9398244ccf 100644 --- a/guides/source/active_record_migrations.md +++ b/guides/source/active_record_migrations.md @@ -225,6 +225,8 @@ class CreateProducts < ActiveRecord::Migration[5.0] create_table :products do |t| t.string :name t.string :part_number + + t.timestamps end end end diff --git a/guides/source/active_support_instrumentation.md b/guides/source/active_support_instrumentation.md index 4868b00bbe..9f15e70da6 100644 --- a/guides/source/active_support_instrumentation.md +++ b/guides/source/active_support_instrumentation.md @@ -643,7 +643,16 @@ The block receives the following arguments: ```ruby ActiveSupport::Notifications.subscribe "process_action.action_controller" do |name, started, finished, unique_id, data| # your own custom stuff - Rails.logger.info "#{name} Received!" + Rails.logger.info "#{name} Received! (started: #{started}, finished: #{finished})" # process_action.action_controller Received (started: 2019-05-05 13:43:57 -0800, finished: 2019-05-05 13:43:58 -0800) +end +``` + +If you are concerned about the accuracy of `started` and `finished` to compute a precise elapsed time then use `ActiveSupport::Notifications.monotonic_subscribe`. The given block would receive the same arguments as above but the `started` and `finished` will have values with an accurate monotonic time instead of wall-clock time. + +```ruby +ActiveSupport::Notifications.monotonic_subscribe "process_action.action_controller" do |name, started, finished, unique_id, data| + # your own custom stuff + Rails.logger.info "#{name} Received! (started: #{started}, finished: #{finished})" # process_action.action_controller Received (started: 1560978.425334, finished: 1560979.429234) end ``` diff --git a/guides/source/configuring.md b/guides/source/configuring.md index 3863323bd2..3adc956ef9 100644 --- a/guides/source/configuring.md +++ b/guides/source/configuring.md @@ -145,7 +145,7 @@ defaults to `:debug` for all environments. The available log levels are: `:debug * `secret_key_base` is used for specifying a key which allows sessions for the application to be verified against a known secure key to prevent tampering. Applications get a random generated key in test and development environments, other environments should set one in `config/credentials.yml.enc`. -* `config.public_file_server.enabled` configures Rails to serve static files from the public directory. This option defaults to `true`, but in the production environment it is set to `false` because the server software (e.g. NGINX or Apache) used to run the application should serve static files instead. If you are running or testing your app in production mode using WEBrick (it is not recommended to use WEBrick in production) set the option to `true.` Otherwise, you won't be able to use page caching and request for files that exist under the public directory. +* `config.public_file_server.enabled` configures Rails to serve static files from the public directory. This option defaults to `true`, but in the production environment it is set to `false` because the server software (e.g. NGINX or Apache) used to run the application should serve static files instead. If you are running or testing your app in production mode using WEBrick (it is not recommended to use WEBrick in production) set the option to `true`. Otherwise, you won't be able to use page caching and request for files that exist under the public directory. * `config.session_store` specifies what class to use to store the session. Possible values are `:cookie_store` which is the default, `:mem_cache_store`, and `:disabled`. The last one tells Rails not to deal with sessions. Defaults to a cookie store with application name as the session key. Custom session stores can also be specified: diff --git a/guides/source/contributing_to_ruby_on_rails.md b/guides/source/contributing_to_ruby_on_rails.md index f86589bdf1..a6eb9907a0 100644 --- a/guides/source/contributing_to_ruby_on_rails.md +++ b/guides/source/contributing_to_ruby_on_rails.md @@ -340,7 +340,7 @@ $ TEST_DIR=generators bundle exec rake test You can run the tests for a particular file by using: ```bash -$ cd actionpack +$ cd actionview $ bundle exec ruby -w -Itest test/template/form_helper_test.rb ``` diff --git a/guides/source/testing.md b/guides/source/testing.md index 18eecf49fa..9540bb2af5 100644 --- a/guides/source/testing.md +++ b/guides/source/testing.md @@ -781,7 +781,7 @@ This can be helpful for viewing the browser at the point a test failed, or to view screenshots later for debugging. Two methods are provided: `take_screenshot` and `take_failed_screenshot`. -`take_failed_screenshot` is automatically included in `after_teardown` inside +`take_failed_screenshot` is automatically included in `before_teardown` inside Rails. The `take_screenshot` helper method can be included anywhere in your tests to diff --git a/guides/source/upgrading_ruby_on_rails.md b/guides/source/upgrading_ruby_on_rails.md index 7e4152aa51..76ee5c0c48 100644 --- a/guides/source/upgrading_ruby_on_rails.md +++ b/guides/source/upgrading_ruby_on_rails.md @@ -133,6 +133,223 @@ Action Cable JavaScript API: + ActionCable.logger.enabled = false ``` +### Autoloading + +The default configuration for Rails 6 + +```ruby +# config/application.rb + +config.load_defaults "6.0" +``` + +enables `zeitwerk` autoloading mode on CRuby. In that mode, autoloading, reloading, and eager loading are managed by [Zeitwerk](https://github.com/fxn/zeitwerk). + +#### Public API + +In general, applications do not need to use the API of Zeitwerk directly. Rails sets things up according to the existing contract: `config.autoload_paths`, `config.cache_classes`, etc. + +While applications should stick to that interface, the actual Zeitwerk loader object can be accessed as + +```ruby +Rails.autoloaders.main +``` + +That may be handy if you need to preload STIs or configure a custom inflector, for example. + +#### Project Structure + +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 +``` + +and then running + +``` +bin/rails zeitwerk:check +``` + +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 entire 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) +``` + +#### Qualified names in class and module definitions + +You can now robustly use constant paths in class and module definitions: + +```ruby +# Autoloading in this class' body matches Ruby semantics now. +class Admin::UsersController < ApplicationController + # ... +end +``` + +A gotcha to be aware of is that, depending on the order of execution, the classic autoloader could sometimes be able to autoload `Foo::Wadus` in + +```ruby +class Foo::Bar + Wadus +end +``` + +That does not match Ruby semantics because `Foo` is not in the nesting, and won't work at all in `zeitwerk` mode. If you find such corner case you can use the qualified name `Foo::Wadus`: + +```ruby +class Foo::Bar + Foo::Wadus +end +``` + +or add `Foo` to the nesting: + +```ruby +module Foo + class Bar + Wadus + end +end +``` + +#### Concerns + +You can autoload and eager load from a standard structure like + +``` +app/models +app/models/concerns +``` + +In that case, `app/models/concerns` is assumed to be a root directory (because it belongs to the autoload paths), and it is ignored as namespace. So, `app/models/concerns/foo.rb` should define `Foo`, not `Concerns::Foo`. + +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. + +#### Autoloaded Constants and Explicit Namespaces + +If a namespace is defined in a file, as `Hotel` is here: + +``` +app/models/hotel.rb # Defines Hotel. +app/models/hotel/pricing.rb # Defines Hotel::Pricing. +``` + +the `Hotel` constant has to be set using the `class` or `module` keywords. For example: + +```ruby +class Hotel +end +``` + +is good. + +Alternatives like + +```ruby +Hotel = Class.new +``` + +or + +```ruby +Hotel = Struct.new +``` + +won't work, child objects like `Hotel::Pricing` won't be found. + +This restriction only applies to explicit namespaces. Classes and modules not defining a namespace can be defined using those idioms. + +#### Spring and the `test` Environment + +Spring reloads the application code if something changes. In the `test` environment you need to enable reloading for that to work: + +```ruby +# config/environments/test.rb + +config.cache_classes = false +``` + +Otherwise you'll get this error: + +``` +reloading is disabled because config.cache_classes is true +``` + +#### Bootsnap + +Bootsnap should be at least version 1.4.2. + +In addition to that, Bootsnap needs to disable the iseq cache due to a bug in the interpreter if running Ruby 2.5. Please make sure to depend on at least Bootsnap 1.4.4 in that case. + +#### `config.add_autoload_paths_to_load_path` + +The new configuration point + +```ruby +config.add_autoload_paths_to_load_path +``` + +is `true` by default for backwards compatibility, but allows you to opt-out from adding the autoload paths to `$LOAD_PATH`. + +This makes sense in most applications, since you never should require a file in `app/models`, for example, and Zeitwerk only uses absolute file names internally. + +By opting-out you optimize `$LOAD_PATH` lookups (less directories to check), and save Bootsnap work and memory consumption, since it does not need to build an index for these directories. + +#### Thread-safety + +In classic mode, constant autoloading is not thread-safe, though Rails has locks in place for example to make web requests thread-safe when autoloading is enabled, as it is common in `development` mode. + +Constant autoloading is thread-safe in `zeitwerk` mode. For example, you can now autoload in multi-threaded scripts executed by the `runner` command. + +#### Globs in config.autoload_paths + +Beware of configurations like + +```ruby +config.autoload_paths += Dir["#{config.root}/lib/**/"] +``` + +Every element of `config.autoload_paths` should represent the top-level namespace (`Object`) and they cannot be nested in consequence (with the exception of `concerns` directories explained above). + +To fix this, just remove the wildcards: + +```ruby +config.autoload_paths << "#{config.root}/lib" +``` + +#### 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: + +```ruby +# config/application.rb + +config.load_defaults "6.0" +config.autoloader = :classic +``` + Upgrading from Rails 5.1 to Rails 5.2 ------------------------------------- @@ -1557,7 +1774,7 @@ config.assets.enabled = true config.assets.version = '1.0' ``` -If your application is using an "/assets" route for a resource you may want change the prefix used for assets to avoid conflicts: +If your application is using an "/assets" route for a resource you may want to change the prefix used for assets to avoid conflicts: ```ruby # Defaults to '/assets' |