You can now configure custom digest for cookies in the same way as `serializer`:

config.action_dispatch.cookies_digest = \SHA256'

Full stack source extract

Fixes to TestCaseTest.

Originally introduced in f9086d63, the documentation of this method is
wrong as #const_regexp returns a string to easy the interpolation inside
regular expressions.

Fix typo in plugins doc

[ci skip] Changed 'first argument' to '+name+ argument'

Provide the ability to extract the source code of the entire exception stack
trace, not just the frame raising the error. This improves debugging
capability of the error page, especially for framework-related errors.

`#create!` regarding validations in contrast to the behavior of
`#create`. Also describe creating multiple objects using an array of
hashes as the +attributes+ parameter. [ci skip] /cc #16384

[ci skip] Added +object+ and +attributes+ to create! description for rdoc

Pull spring gem entry into the Gemfile template instead of gemfile_entries so it can be grouped with the other development tools

remove dead file_watcher code

Tables existence check query is executed in large quantities

Closes #16422

When Rails starts, tables existence check query is executed
number of models.
In case of mysql,

    SHOW TABLES LIKE 'table1';
    SHOW TABLES LIKE 'table2';
    SHOW TABLES LIKE 'table3';
    ...
    SHOW TABLES LIKE 'table999';

Add process to get the names of all tables by one query.

Fix in has_secure_password for passwords containing only spaces.

Remove ActionController::RaiseActionExceptions.

The latest modification to the code was done in https://github.com/rails/rails/commit/5e3517ea. In Rails 3.2,
`ActionController#rescue_action` was deprecated and `rescue_action_without_handler` is no longer being used.

Currently when we call id_was and we have a custom primary key name
Active Record will return the current value of the primary key. This
make impossible to correctly do an update operation if you change the
id.

Fixes #16413

See
https://github.com/rails/turbolinks/commit/153f1b0f04c718442cfd73365a2778dfe1a1c5c7

Fixes #16406

this means we can meaningfully override methods in the subclass

So this trick is not needed to be documented anymore.

Fixed #select form builder helper to support block without html output