It appears that Oracle does not allow using aliases in GROUP BY clause
unlike ORDER BY clause.

Fixes #36613.

Set process title of parallelized test workers

Fix Browser#preload for older Selenium

MySQL: Fix schema dumping `enum` and `set` columns correctly

Update docs on dirty.rb

[ci skip]

`previously_changed` seems to actually be `previous_changes`

`enum` and `set` are typed cast as `:string`, but currently the
`:string` type is incorrectly reused for schema dumping.

A cast type on columns is not always the same with `sql_type`, this
fixes schema dumping `enum` and `set` columns to use `sql_type` instead
of `type` correctly.

Since #36424, we need an newer version in order to pass.

Older versions of selenium had driver_path on
::Selenium::WebDriver::Chrome directly, not on Service. This avoids
errors on those old versions and will preload properly if webdrivers is
installed.

Preload browser driver_path to fix system testing under parallelism

Update docs regarding skipping CI tests [ci skip]

The phrasing of this struck we as odd, "To help our CI servers..." So I
feel it would be more useful if we explain more explicitly that ci skip
cuts down on usage by not running CI.

The webdrivers gem configures Selenium::WebDriver::Service.driver_path
as a proc which updates the web drivers and returns their path.

This commit introduces SystemTesting::Browser#preload, which runs this
proc early. This ensures that webdrivers update is run before forking
for parallel testing, but doesn't explicitly tie us to that gem (and I
think anything configured as driver_path probably makes sense to
eager-load).

Fix swapped replica/primary in multi-db docs [ci skip]

Add the ability to set the CSP nonce only to the specified directives

Replace replica with primary in automatic connection switching after write in multi-db docs [ci skip]

Reads after write should be from the primary database.

This reverts commit 60e19c6d, reversing
changes made to 72e257b4.

The method signature is different between `create_file` and `template`.

https://www.rubydoc.info/github/erikhuda/thor/master/Thor/Actions#create_file-instance_method
https://www.rubydoc.info/github/erikhuda/thor/master/Thor/Actions#template-instance_method

[skip ci] use 'template' instead of 'create_file' for erb templates in generators guide

This version makes eager loading and autoloading consistent,
as documented in the upgrading guide.

This makes to be able to ignore the query in `assert_queries` even if
accidentally reconnected a connection.

https://buildkite.com/rails/rails/builds/61917#4c49187a-3173-4d5c-8a8d-d65768f5bfc9/1000-1799

Introduced in bba7c63a

Before:

```
$ TESTOPTS="-n=/test_yaml_dump_and_load/" bundle exec rake
test:postgresql

:scisors: ... :scisors:

Using postgresql
Run options: -n=/test_yaml_dump_and_load/ --seed 36896

/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
/home/u/code/rails/activerecord/lib/active_record/connection_adapters/postgresql/column.rb:15:
warning: instance variable @serial not initialized
.

Finished in 0.195325s, 5.1197 runs/s, 35.8376 assertions/s.
1 runs, 7 assertions, 0 failures, 0 errors, 0 skips

```
Co-authored-by: NRyuta Kamizono <kamipo@gmail.com>

Fix broken url configs

This PR is to fix #36559 but I also found other issues that haven't been
reported.

The check for `(config.size == 1 && config.values.all? { |v| v.is_a?
String })` was naive. The only reason this passed was because we had
tests that had single hash size configs, but that doesn't mean we don't
want to create a hash config in other cases. So this now checks for
`config["database"] || config["adapter"] || ENV["DATABASE_URL"]`. In the
end for url configs we still get a UrlConfig but we need to pass through
the HashConfig to create the right kind of UrlConfig. The UrlConfig's
are really complex and I don't necessarily understand everything that's
needed in order to act the same as Rails 5.2.

I edited the connection handler test to demonstrate how the previous
implementation was broken when checking config size. Now old and new
tests pass so I think this is closer to 5.2.

Fixes #36559

Address to "DEPRECATION WARNING: Uniqueness validator will no longer enforce case sensitive comparison in Rails 6.1"

Caused by #36210.

Warn if we can't read the yaml to create database tasks

For multiple databases we attempt to generate the tasks by reading the
database.yml before the Rails application is booted. This means that we
need to strip out ERB since it could be reading Rails configs.

In some cases like https://github.com/rails/rails/issues/36540 the ERB
is too complex and we can't overwrite with the DummyCompilier we used in
https://github.com/rails/rails/pull/35497. For the complex causes we
simply issue a warning that says we couldn't infer the database tasks
from the database.yml.

While working on this I decided to update the code to only load the
database.yml once initially so that we avoid having to issue the same
warning multiple times. Note that this had no performance impact in my
testing and is merely for not having to save the error off somewhere.
Also this feels cleaner.

Note that this will not break running tasks that exist, it will just
mean that tasks for multi-db like `db:create:other_db` will not be
generated. If the database.yml is actually unreadable it will blow up
during normal rake task calls.

Fixes #36540

https://github.com/vhf/free-programming-books seems to have moved to
https://github.com/EbookFoundation/free-programming-books

[ci skip] Refer actionmailbox and actiontext in the guide

Replace the www.robotstxt.org URL with https one [ci skip]

The robots.txt site is moved permanently to https URL.

Rely on Kernel require instead of self require

Merge pull request #36210 from vishaltelangre/raise-record-invalid-when-associations-fail-to-save-due-to-uniqueness-failure

Fix: ActiveRecord::RecordInvalid is not raised when an associated record fails to #save! due to uniqueness validation failure