has_many :through with dynamic condition merging

Fix typo in rdoc [ci skip]

Deprecated ActionMailer .deliver and updated ActionMailer / ActiveJob docs/guide

Require ActiveJob in case a skip_xxx option is given

Change position of require active_job

[ci skip] Format pass of Active Job Basics guide.

Zero has one digit, but Math.log10(0) returns -Infinity. The method
needs to special-case zero.

The patch adds a regression test that is not clearly related to the
underlying issue because digit_count is private and has no coverage.
Gray area.

This bug was uncovered by 60062cf3.

don't log errors when all is fine

Move as/test_test to as/test_case_test

Revert "Do not gsub non ASCII characters in header anchor.".

This reverts commit 699babe8.

Also change the upgrading_ruby_on_rails link back to original in 4_2_release_notes.

Updated the deprecation warnings to 5.0

Remove end-of-line spacing in development.rb, production.rb

Also moved comment for removal above `unless()` to not confuse RDoc with
the documentation for this method.

with dynamic conditions.

Fixes #16128

This bug was introduced in https://github.com/rails/rails/commit/c35e438620f2d56562251571377995359546393d
so it's present from 4.1.2-rc1 and after.

https://github.com/rails/rails/commit/c35e438620f2d56562251571377995359546393d
merges any relation scopes passed as proc objects to the relation,
but does *not* take into account the arity of the lambda.

To reproduce: https://gist.github.com/Agis-/5f1f0d664d2cd08dfb9b

Remove global helpers from the ActionMailer test suite.

Add `set_delivery_method` and `restore_delivery_method` to `ActionMailer::TestCase.

This way these methods are available outside the ActionMailer test suite, but
they are still duplicated inside `test/abstract_unit` for test cases that don't
inherit from the `ActionMailer::TestCase` class.

A combination of two commits led into these failures:

* The addition of a new active_record config in
  24bb8347
* The revert of the config to use config.x as options holder in
  43073b39

These tests remove activerecord from the load path, however the
configuration is still in the application file, and they blow up.