Merge pull request #17227 from claudiob/explicitly-abort-callbacks

Introduce explicit way of halting callback chains by throwing :abort. Deprecate current implicit behavior of halting callback chains by returning `false` in apps ported to Rails 5.0. Completely remove that behavior in brand new Rails 5.0 apps.

Conflicts:
	railties/CHANGELOG.md

1 files changed, 15 insertions, 0 deletions

diff --git a/railties/CHANGELOG.md b/railties/CHANGELOG.md
index 588cea8886..5367a4dd0e 100644
--- a/railties/CHANGELOG.md
+++ b/railties/CHANGELOG.md
@@ -1,3 +1,18 @@
+*   Add `config/initializers/callback_terminator.rb`
+
+    Newly generated Rails apps have a new initializer called
+    `callback_terminator.rb` which sets the value of the configuration option
+    `config.active_support.halt_callback_chains_on_return_false` to `false`.
+
+    As a result, new Rails apps do not halt callback chains when a callback
+    returns `false`; only when they are explicitly halted with `throw(:abort)`.
+
+    The terminator is *not* added when running `rake rails:update`, so returning
+    `false` will still work on old apps ported to Rails 5, displaying a
+    deprecation warning to prompt users to update their code to the new syntax.
+
+    *claudiob*
+
 *   Generated fixtures won't use the id when generated with references attributes.
 
     *Pablo Olmos de Aguilera Corradini*