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| -rw-r--r-- | guides/source/upgrading_ruby_on_rails.md | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/guides/source/upgrading_ruby_on_rails.md b/guides/source/upgrading_ruby_on_rails.md index de06ab291f..9be48acb12 100644 --- a/guides/source/upgrading_ruby_on_rails.md +++ b/guides/source/upgrading_ruby_on_rails.md @@ -93,6 +93,39 @@ 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 you to `return` from an inline callback block: + +```ruby +class ReadOnlyModel < ActiveRecord::Base + before_save { return false } +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 will cause a `LocalJumpError` to +be raised when the callback is executed. If you need to use `return` statements +in your callbacks, it is recommended that you explicitly define them as methods +and pass the method name as a symbol instead: + +```ruby +class ReadOnlyModel < ActiveRecord::Base + before_save :before_save_callback + + 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 |