Remove j alias for ERB::Util.json_escape
Fix eagerly loading associations without primary keys
Unset association when existing record is destroyed.

To avoid foreign key errors (and invalid data) in the database, when a belongs_to association is destroyed, it should also be nil'd out on the parent object.
AR::Relation#model would be a better API than AR::Relation#klass
Change JoinPart test from an integration to a unit test
Document default_options configuration in ActionMailer guide [ci skip]
Add extra documentation to the locale file.
Refactored common date and time calculations.

* Added the `DateAndTime::Calculations` module that is included in Time
  and Date. It houses common calculations to reduce duplicated code.
* Simplified and cleaned-up the calculation code.
* Removed duplication in tests by adding a behavior module for shared
  tests. I also added some missing tests.
edit of previous content
 explains how to add/override engine classes in the main rails app via
1) Class#class_eval
2) ActiveSupport::Concern
AM::Validation#validates: ability to pass custom exception to `:strict` option
Update list of finder methods
For adding non css/js files to precompile array
Fix #7191. Remove unnecessary transaction when assigning has_one associations.
add around_create callback documentation for ActiveModel::Callbacks
Added a note for smtp_settings.enable_starttls_auto
Document the namespacing of controller actions per this discussion:

https://github.com/rails/journey/issues/40
RouteSet: refactor internals

No need to build valid_conditions array.
We can get all the data in place.
Add 'X-Frame-Options' => 'SAMEORIGIN' and 'X-XSS-Protection' => '1; mode=block' CHANGELOG entry
Merge pull request #7286 from kennyj/fix_7191

Fix #7191. Remove unnecessary transaction when assigning has_one associations.
Remove the dependent_restrict_raises option.

It's not really a good idea to have this as a global config option. We
should allow people to specify the behaviour per association.

There will now be two new values:

* :dependent => :restrict_with_exception implements the current
  behaviour of :restrict. :restrict itself is deprecated in favour of
  :restrict_with_exception.
* :dependent => :restrict_with_error implements the new behaviour - it
  adds an error to the owner if there are dependent records present

See #4727 for the original discussion of this.