- Remove
```
* Namespace error pages' CSS selectors to stop the styles from bleeding
into other pages when using Turbolinks.
([Pull Request](https://github.com/rails/rails/pull/28814))
```
since it was backported to
`5-1-stable` by 50d5baf7ed15908ce66c39cc62ce80ad99e313c3
and
`5-0-stable` by d1c4a39ed796a31efc51901e7e818609fb3cb7ec.
- Remove
```
* Allow irb options to be passed from `rails console` command.
([Pull Request](https://github.com/rails/rails/pull/29010))
```
since it was backported to
`5-1-stable` by e91b48348c9a33447bf1bff6e043c043cf36439f.
- Remove
```
* Load environment file in `dbconsole` command.
([Pull Request](https://github.com/rails/rails/pull/29725))
```
since it was backported to
`5-1-stable` by 7f9342877a80bc9a2a283462babf7b829902dc78.
- Remove
```
* Gemfile for new apps: upgrade redis-rb from ~> 3.0 to 4.0.
([Pull Request](https://github.com/rails/rails/pull/30748))
```
since it was backported to
`5-1-stable` by 37895311514a35333e5597018852eb0fe2c9eb28.
- Remove
```
* Fix minitest rails plugin.
The custom reporters are added only if needed.
This will fix conflicts with others plugins.
([Commit](ac99916fcf))
```
since it was backported to
`5-1-stable` by caa76956d396a6a9feae7aa17adce784127e92cc.
- Remove
```
* Add support for compatibility with redis-rb gem for 4.0 version.
([Pull Request](https://github.com/rails/rails/pull/30748))
```
since it was backported to
`5-1-stable` by 37895311514a35333e5597018852eb0fe2c9eb28.
- Remove
```
* Add `action_controller_api` and `action_controller_base` load hooks to be
called in `ActiveSupport.on_load`.
([Pull Request](https://github.com/rails/rails/pull/28402))
```
since it was backported to
`5-1-stable` by b9a5fd706a821401cbe3ce11d7a18daa8267588f.
- Remove
```
* `driven_by` now registers poltergeist and capybara-webkit.
([Pull Request](https://github.com/rails/rails/pull/29315))
```
since it was backported to
`5-1-stable` by c5dd45119a28fb1c41de6d27d63443480c86894e.
- Remove
```
* Fallback `ActionController::Parameters#to_s` to `Hash#to_s`.
([Pull Request](https://github.com/rails/rails/pull/29630))
```
since it was backported to
`5-1-stable` by c1014e435d26db867b2c15b74c9ef47ccff38edb
and
`5-0-stable` by 0e71fc3040edc3c28d12c07300f0162559bbe4e5.
- Remove
```
* Make `take_failed_screenshot` work within engine.
([Pull Request](https://github.com/rails/rails/pull/30421))
```
since it was backported to
`5-1-stable` by 595a231029ce402445da33eec62775cbe0da97de.
- Remove
```
* Fix optimized url helpers when using relative url root.
([Pull Request](https://github.com/rails/rails/pull/31261))
```
since it was backported to
`5-1-stable` by e9b77953a277a707ce1fb60e1f9963a833df9312.
- Remove
```
* Update `distance_of_time_in_words` helper to display better error messages
for bad input.
([Pull Request](https://github.com/rails/rails/pull/20701))
```
since it was backported to
`5-1-stable` by 2c97fbf6503c9199f3fe5ed06222e7226dc6fcd9.
- Remove
```
* Generate field ids in `collection_check_boxes` and
`collection_radio_buttons`.
([Pull Request](https://github.com/rails/rails/pull/29412))
```
since it was backported to
`5-1-stable` by 2d8c10a7b1066d6a577096b4a86e310f1b0d2c22.
- Remove
```
* Fix issues with scopes and engine on `current_page?` method.
([Pull Request](https://github.com/rails/rails/pull/29503))
```
since it was backported to
`5-1-stable` by 2135daf0d552bbb2eca4208f8c33fb015cf052ab.
- Remove
```
* Bring back proc with arity of 1 in `ActionMailer::Base.default` proc
since it was supported in Rails 5.0 but not deprecated.
([Pull Request](https://github.com/rails/rails/pull/30391))
```
since it was backported to
`5-1-stable` by b2bedb149274c8490c782c62dd8ab0bbae6a9730.
- Remove
```
* Add type caster to `RuntimeReflection#alias_name`.
([Pull Request](https://github.com/rails/rails/pull/28961))
```
since it was backported to
`5-1-stable` by f644e7a6fddf1b239dc1af0b0c6be8af9f776918.
- Remove
```
* Loading model schema from database is now thread-safe.
([Pull Request](https://github.com/rails/rails/pull/29216))
```
since it was backported to
`5-1-stable` by 02926cfff6a403d28f83903b08ae7375fad8e836.
and
`5-0-stable` by 84bcfe5a6a65d3c2998d14b85b9f02560d3f9e98
- Remove
```
* Fix destroying existing object does not work well when optimistic locking
enabled and `locking_column` is null in the database.
([Pull Request](https://github.com/rails/rails/pull/28926))
```
since it was backported to
`5-1-stable` by e498052c5210e886f46c61deadd161f8ea41666f.
- Remove
```
* `ActiveRecord::Persistence#touch` does not work well
when optimistic locking enabled and `locking_column`,
without default value, is null in the database.
([Pull Request](https://github.com/rails/rails/pull/28914))
```
since it was backported to
`5-1-stable` by 1e2f63db78b9089fb7011eb954c88136f324e7c0.
- Remove
```
* Previously, when building records using a `has_many :through` association,
if the child records were deleted before the parent was saved,
they would still be persisted. Now, if child records are deleted
before the parent is saved on a `has_many :through` association,
the child records will not be persisted.
([Pull Request](https://github.com/rails/rails/pull/29593))
```
since it was backported to
`5-1-stable` by a22c39e9cc08c052bb5c828b45533e5a01c896f1.
- Remove
```
* Query cache was unavailable when entering the `ActiveRecord::Base.cache`
block without being connected.
([Pull Request](https://github.com/rails/rails/pull/29609))
```
since it was backported to
`5-1-stable` by fd6c8cdfe69ed3a0763f0ff1dc41d2d2ee2e8752
and
`5-0-stable` by 9f2532bb16b49751fbdda51846b156c3eca09054.
- Remove
```
* `Relation#joins` is no longer affected by the target model's
`current_scope`, with the exception of `unscoped`.
([Commit](5c71000d08))
```
since it was backported to
`5-1-stable` by 3630d6354cab31bb233a1f1d7b1a4d2c24aef54d.
- Remove
```
* Fix `unscoped(where: [columns])` removing the wrong bind values.
([Pull Request](https://github.com/rails/rails/pull/29780))
```
since it was backported to
`5-1-stable` by d378fcb254462f9da8d921f0fa2e9b9868a7d34e.
- Remove
```
* When a `has_one` association is destroyed by `dependent: destroy`,
`destroyed_by_association` will now be set to the reflection, matching the
behaviour of `has_many` associations.
([Pull Request](https://github.com/rails/rails/pull/29855))
```
since it was backported to
`5-1-stable` by 8254a8be81c07dbdbc2a281bab72f23f93f6b12f.
- Remove
```
* Fix `COUNT(DISTINCT ...)` with `ORDER BY` and `LIMIT`
to keep the existing select list.
([Pull Request](https://github.com/rails/rails/pull/29848))
```
since it was backported to
`5-1-stable` by 0e8d4edd56f44b27f33bd214aa03af60cc5d39ae.
- Remove
```
* Ensure `sum` honors `distinct` on `has_many :through` associations.
([Commit](566f1fd068))
```
since it was backported to
`5-1-stable` by c0a1dc256144b91aee5241fad2121e85e6d8093f.
- Remove
```
* Fix `COUNT(DISTINCT ...)` for `GROUP BY` with `ORDER BY` and `LIMIT`.
([Commit](5668dc6b18))
```
since it was backported to
`5-1-stable` by 87ca68e76eec68ec61fc0d3d3bf315b4bfe45c42.
- Remove
```
* MySQL: Don't lose `auto_increment: true` in the `db/schema.rb`.
([Commit](9493d45535))
```
since it was backported to
`5-1-stable` by 8b6e694e5febdcb39f72d98ff9d5e7124cc0ca32.
- Remove
```
* Fix longer sequence name detection for serial columns.
([Pull Request](https://github.com/rails/rails/pull/28339))
```
since it was backported to
`5-1-stable` by af9c1707ad49eb421cf76c1367da3efbf3c39aea
and
`5-0-stable` by 7025b1d8ebf694c288c71878b5229394ba3c0580.
- Remove
```
* Fix `bin/rails db:setup` and `bin/rails db:test:prepare` create wrong
ar_internal_metadata's data for a test database.
([Pull Request](https://github.com/rails/rails/pull/30579))
```
since it was backported to
`5-1-stable` by bb67b5f278c2dbca65b9dd03038788a4dbb4a21f
and
`5-0-stable` by 60437e6d3c99cbbb95a01f31d44be19f7b63e3eb.
- Remove
```
* Fix conflicts `counter_cache` with `touch: true` by optimistic locking.
([Pull Request](https://github.com/rails/rails/pull/31405))
```
since it was backported to
`5-1-stable` by 5236ddaf35492513895d4a706435520e74ab723b.
- Remove
```
* Fix `count(:all)` to correctly work `distinct` with custom SELECT list.
([Commit](c6cd9a59f2))
```
since it was backported to
`5-1-stable` by 6beb4de7dd5205d9b08ce4eedbe383cb0b18540d.
- Remove
```
* Fix to invoke callbacks when using `update_attribute`.
([Commit](732aa34b6e))
```
since it was backported to
`5-1-stable` by 6346683bc58b79b2745e9305e65a6f1f1a63c288.
- Remove
```
* Use `count(:all)` in `HasManyAssociation#count_records` to prevent invalid
SQL queries for association counting.
([Pull Request](https://github.com/rails/rails/pull/27561))
```
since it was backported to
`5-1-stable` by eef3c89e3b38c99c79decb1ec5d6854f4ab9ea18.
- Remove
```
* Fix `count(:all)` with eager loading and having an order other than
the driving table.
([Commit](ebc09ed9ad))
```
since it was backported to
`5-1-stable` by 6df9b69b2363734175d8869393e83e6ce8b4d7b6.
- Remove
```
* PostgreSQL: Allow pg-1.0 gem to be used with Active Record.
([Pull Request](https://github.com/rails/rails/pull/31671))
```
since it was backported to
`5-1-stable` by a9c06f61d52c7cf03dc413dd50e9a9c5ab580703.
- Remove
```
* Fix that after commit callbacks on update does not triggered
when optimistic locking is enabled.
([Commit](7f9bd034c4))
```
since it was backported to
`5-1-stable` by aaee10e6e4fdfbc8bb7dc6169ed9deea3638c5a8.
- Remove
```
* Fix regression in numericality validator when comparing Decimal and Float
input values with more scale than the schema.
([Pull Request](https://github.com/rails/rails/pull/28584))
```
since it was backported to
`5-1-stable` by 5b1c3e5a8b02d0078bd2527ca0969b0d89fec433.
Note that there was incorrect link to PR,
original PR is https://github.com/rails/rails/pull/29249.
- Remove
```
* Fix to working before/after validation callbacks on multiple contexts.
([Pull Request](https://github.com/rails/rails/pull/31483))
```
since it was backported to
`5-1-stable` by 0f7046a7f820186fd6fbe19a6142002cb8537fe6.
- Remove
```
* Fix implicit coercion calculations with scalars and durations.
([Pull Request](https://github.com/rails/rails/pull/29163),
[Pull Request](https://github.com/rails/rails/pull/29971))
```
since it was backported to
`5-1-stable` by 51ea27c04c60373d97e212389d587821deae6fe0,
4d82e2aad98ddf7c1a54e588288dcf1f68ad7af4.
- Remove
```
* Fix modulo operations involving durations.
([Commit](a54e13bd2e))
```
since it was backported to
`5-1-stable` by 233fa7eab36e7d6fb515b2e55c699bff9858ea5f.
- Remove
```
* Return all mappings for a timezone identifier in `country_zones`.
([Commit](cdce6a709e))
```
since it was backported to
`5-1-stable` by 0222ebbe0695fd1fbaf98e64333d9d7b285a54ed.
- Remove
```
* Add support for compatibility with redis-rb gem for 4.0 version.
([Pull Request](https://github.com/rails/rails/pull/30748))
```
since it was backported to
`5-1-stable` by 37895311514a35333e5597018852eb0fe2c9eb28.
Related to #32252.
Related to #32222, https://github.com/rails/rails/pull/32222#discussion_r174256536.
Follow up a489cc81b6aa1187b169ddccc92f4c077fe0408f.
b5b179fb57