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Diffstat (limited to 'guides/source/upgrading_ruby_on_rails.md')
| -rw-r--r-- | guides/source/upgrading_ruby_on_rails.md | 51 |
1 files changed, 48 insertions, 3 deletions
diff --git a/guides/source/upgrading_ruby_on_rails.md b/guides/source/upgrading_ruby_on_rails.md index 596682bb1f..ca5623bf73 100644 --- a/guides/source/upgrading_ruby_on_rails.md +++ b/guides/source/upgrading_ruby_on_rails.md @@ -31,9 +31,9 @@ NOTE: This section is a work in progress. If you want to use Spring as your application preloader you need to: -1. add `gem 'spring', group: :development` to your `Gemfile`. -2. install spring using `bundle install`. -3. springify your binstubs with `bundle exec spring binstub --all`. +1. Add `gem 'spring', group: :development` to your `Gemfile`. +2. Install spring using `bundle install`. +3. Springify your binstubs with `bundle exec spring binstub --all`. NOTE: User defined rake tasks will run in the `development` environment by default. If you want them to run in other environments consult the @@ -93,6 +93,51 @@ If you application depends on one of these features, you can get them back by adding the [`activesupport-json_encoder`](https://github.com/rails/activesupport-json_encoder) gem to your Gemfile. +### Usage of `return` within inline callback blocks + +Previously, Rails allowed inline callback blocks to use `return` this way: + +```ruby +class ReadOnlyModel < ActiveRecord::Base + before_save { return false } # BAD +end +``` + +This behaviour was never intentionally supported. Due to a change in the internals +of `ActiveSupport::Callbacks`, this is no longer allowed in Rails 4.1. Using a +`return` statement in an inline callback block causes a `LocalJumpError` to +be raised when the callback is executed. + +Inline callback blocks using `return` can be refactored to evaluate to the +returned value: + +```ruby +class ReadOnlyModel < ActiveRecord::Base + before_save { false } # GOOD +end +``` + +Alternatively, if `return` is preferred it is recommended to explicitly define +a method: + +```ruby +class ReadOnlyModel < ActiveRecord::Base + before_save :before_save_callback # GOOD + + private + def before_save_callback + return false + end +end +``` + +This change applies to most places in Rails where callbacks are used, including +Active Record and Active Model callbacks, as well as filters in Action +Controller (e.g. `before_action`). + +See [this pull request](https://github.com/rails/rails/pull/13271) for more +details. + ### Methods defined in Active Record fixtures Rails 4.1 evaluates each fixture's ERB in a separate context, so helper methods |