From 9c65c539e2caa4590aded1975aead008f8135da4 Mon Sep 17 00:00:00 2001 From: claudiob Date: Wed, 24 Dec 2014 09:58:19 +0100 Subject: Add config to halt callback chain on return false This stems from [a comment](rails#17227 (comment)) by @dhh. In summary: * New Rails 5.0 apps will not accept `return false` as a way to halt callback chains, and will not display a deprecation warning. * Existing apps ported to Rails 5.0 will still accept `return false` as a way to halt callback chains, albeit with a deprecation warning. For this purpose, this commit introduces a Rails configuration option: ```ruby config.active_support.halt_callback_chains_on_return_false ``` For new Rails 5.0 apps, this option will be set to `false` by a new initializer `config/initializers/callback_terminator.rb`: ```ruby Rails.application.config.active_support.halt_callback_chains_on_return_false = false ``` For existing apps ported to Rails 5.0, the initializers above will not exist. Even running `rake rails:update` will not create this initializer. Since the default value of `halt_callback_chains_on_return_false` is set to `true`, these apps will still accept `return true` as a way to halt callback chains, displaying a deprecation warning. Developers will be able to switch to the new behavior (and stop the warning) by manually adding the line above to their `config/application.rb`. A gist with the suggested release notes to add to Rails 5.0 after this commit is available at https://gist.github.com/claudiob/614c59409fb7d11f2931 --- guides/source/configuring.md | 2 ++ guides/source/upgrading_ruby_on_rails.md | 22 ++++++++++++++++++++++ 2 files changed, 24 insertions(+) (limited to 'guides/source') diff --git a/guides/source/configuring.md b/guides/source/configuring.md index 0a375d7cb8..5baab8a4b5 100644 --- a/guides/source/configuring.md +++ b/guides/source/configuring.md @@ -507,6 +507,8 @@ There are a few configuration options available in Active Support: * `config.active_support.time_precision` sets the precision of JSON encoded time values. Defaults to `3`. +* `config.active_support.halt_callback_chains_on_return_false` specifies whether ActiveRecord, ActiveModel and ActiveModel::Validations callback chains can be halted by returning `false` in a 'before' callback. Defaults to `true`. + * `ActiveSupport::Logger.silencer` is set to `false` to disable the ability to silence logging in a block. The default is `true`. * `ActiveSupport::Cache::Store.logger` specifies the logger to use within cache store operations. diff --git a/guides/source/upgrading_ruby_on_rails.md b/guides/source/upgrading_ruby_on_rails.md index 0b9f59bb46..c0c94475e0 100644 --- a/guides/source/upgrading_ruby_on_rails.md +++ b/guides/source/upgrading_ruby_on_rails.md @@ -53,6 +53,28 @@ Don't forget to review the difference, to see if there were any unexpected chang Upgrading from Rails 4.2 to Rails 5.0 ------------------------------------- +### Halting callback chains by returning `false` + +In Rails 4.2, when a 'before' callback returns `false` in ActiveRecord, +ActiveModel and ActiveModel::Validations, then the entire callback chain +is halted. In other words, successive 'before' callbacks are not executed, +and neither is the action wrapped in callbacks. + +In Rails 5.0, returning `false` in a callback will not have this side effect +of halting the callback chain. Instead, callback chains must be explicitly +halted by calling `throw(:abort)`. + +When you upgrade from Rails 4.2 to Rails 5.0, returning `false` in a callback +will still halt the callback chain, but you will receive a deprecation warning +about this upcoming change. + +When you are ready, you can opt into the new behavior and remove the deprecation +warning by adding the following configuration to your `config/application.rb`: + + config.active_support.halt_callback_chains_on_return_false = false + +See [#17227](https://github.com/rails/rails/pull/17227) for more details. + Upgrading from Rails 4.1 to Rails 4.2 ------------------------------------- -- cgit v1.2.3