Fix "autosave: true" on belongs_to of join model causes invalid records to be saved

PostgreSQL: Fix GROUP BY with ORDER BY virtual count attribute

Fix sqlite3 collation parsing when using decimal columns.

* Make ActiveRecord `ConnectionPool.connections` thread-safe.

ConnectionPool documentation is clear on the need to synchronize
access to @connections but also states that public methods do not
require synchronization. Existing code exposed @connections
directly via attr_reader. The fix uses synchronize() to lock
@connections then returns a copy to the caller using Array.dup().

Includes comments on the connections method that thread-safe access
to the connections array does not imply thread-safety of accessing
methods on the actual connections.

Adds a test-case that modifies the pool using a supported method
in one thread  while a second thread accesses pool.connections.
The test fails without this patch.

Fixes #36465.

* Update activerecord/test/cases/connection_pool_test.rb

[jeffdoering + Rafael Mendonça França]

Fix callbacks on has_many :through associations

* Bump RAILS_VERSION
* Bundle
* rake update_versions
* rake changelog:header

Fix different `count` calculation when using `size` with DISTINCT `select`

Fix prepared statements caching to be enabled even when query caching is enabled

Don't allow `where` with invalid value matches to nil values

Restore an ability that class level `update` without giving ids

Fix join table column quoting with SQLite.

Ensure that `delete_all` on collection proxy returns affected count

Reset scope after collection delete

Fix the scoping with query methods in the scope block

Fix the scoping with query methods in the scope block

Allow aliased attributes in update

Allow aliased attributes in update

Allow spaces in postgres table names

Additional types of ResultSet should not contain keys of #attributes_to_define_after_schema_loads

Pluralized enum raises error when attempting to modify

Previosly, `update_columns` would just take whatever keys you gave it
and tried to run the update query. Most likely this would result in an
error from the database. However, if the column actually did exist, but
was in `ignored_columns`, this would result in the method returning
successfully when it should have raised, and an attribute that should
not exist written to `@attributes`.

Fix Collection cache key with limit and custom select

Make sure there are no duplicated nested records with create_with

* PostgreSQL 10 new relkind for partitioned tables

Starting with PostgreSQL 10, we can now have partitioned tables natively

* Add comment

* Remove extra space

* Add test for partition table in postgreSQL10

* Select 'p' for "BASE TABLE" and add a test case
to support PostgreSQL 10 partition tables

* Address RuboCop offense

* Addressed incorrect `postgresql_version`

Fixes #33008.

[Yannick Schutz & Yasuo Honda & Ryuta Kamizono]

Fix default value for mysql time types with specified precision

`touch` option was added to `increment!` (#27660) and `update_counters`
(#26995). But that option behaves inconsistently with
`Persistence#touch` method.

If `touch` option is passed attribute names, it won't update
update_at/on attributes unlike `Persistence#touch` method.

Due to changed from `Persistence#touch` to `increment!` with `touch`
option, #31405 has a regression that `counter_cache` with `touch` option
which is passed attribute names won't update update_at/on attributes.

I think that the inconsistency is not intended. To get back consistency,
ensure that `touch` option updates update_at/on attributes.

Since a record is already persisted in `after_create_commit`, so `save`
should invoke only `after_update_commit`.

This bug is caused by depending on `@_start_transaction_state` for
rollback to consider whether it was `new_record` before being committed.

If after commit callbacks caused another commit, the state before
last commit is no longer `new_record`.

Fixes #32831.
Closes #18367.
Closes #31106.

Fix logic on disabling afer_commit callbacks

Fix parent record should not get saved with duplicate children records

Since #31405, using `#increment!` with touch option instead of `#touch`
to touch belongs_to association if counter cache is enabled. It caused
the regression since `#increment!` won't invoke after_touch callbacks
even if touch option is given.
To fix the regression, make `#increment!` invokes after_touch callbacks
if touch option is given.

Fixes #31559.
Fixes #32408.

`becomes` creates new object and copies attributes from the receiver. If
new object has mutation tracker which is created in `after_initialize`,
it should be cleared since it is for discarded attributes.

But if the receiver doesn't have mutation tracker yet, it will not be
cleared properly.

It should be cleared regardless of whether the receiver has mutation
tracker or not.

Fixes #32867.

Allow a belonging to object to be created from a new record