The `:include_blank` option of various `<select>`-related helpers causes
an `<option>` element with no content to be rendered.  However, the
[HTML spec] says that unless an `<option>` element has a `label`
attribute (which must be non-empty), its content must be "Text that is
not inter-element whitespace."

In #24923, this issue was addressed for `select_tag` by adding a `label`
attribute to the `<option>`.  This commit addresses the issue in the
same manner for `FormBuilder#select` and various date / time select
helpers.

[HTML spec]: https://html.spec.whatwg.org/multipage/form-elements.html#the-option-element

Alter regexp on initialize to avoid extra ast pass

Refactor `process` method

Awhile back tenderlove and I worked to improve performance of
integration tests and remove controller tests. The second never
happened, we ended up soft deprecating them but never did that
completely.

Now that we're revisting that work we need a way to override these two
methods in tests so that we can convert tests in Rails to be integration
tests instead of controller tests. Splitting these two concerns into two
methods allows us to overwrite them to work for our needs while
refactoring the test harness code.

These methods are private because they should not be used by an
application or gems, they will be removed when the refactoring has been
completed.
Co-authored-by: NAaron Patterson <tenderlove@ruby-lang.org>

Along the same lines as #38901, #39903, and #39914, this commit removes
one pass through the journey ast in an attempt to improve application
boot time.

Before this commit, `Mapper#path` would iterate through the ast to alter
the regex for custom routes. With this commit we move the regex
alterations to initialize, where we were already iterating through the
ast.

The Benchmark for this change is similar to what we have been seeing in
the other PRs.

```
Warming up --------------------------------------
               after    13.121k i/100ms
              before     7.416k i/100ms
Calculating -------------------------------------
               after    128.469k (± 3.1%) i/s -    642.929k in 5.009391s
              before     76.561k (± 1.8%) i/s -    385.632k in 5.038677s

Comparison:
               after:   128469.4 i/s
              before:    76560.8 i/s - 1.68x  (± 0.00) slower

Calculating -------------------------------------
               after   160.000  memsize (     0.000  retained)
                         3.000  objects (     0.000  retained)
                         0.000  strings (     0.000  retained)
              before   360.000  memsize (     0.000  retained)
                         6.000  objects (     0.000  retained)
                         0.000  strings (     0.000  retained)

Comparison:
               after:        160 allocated
              before:        360 allocated - 2.25x more
```

Move Arel attribute normalization into `arel_table`

Use `arel_table` directly instead.

Consolidate passes through path ast

Along the same lines as https://github.com/rails/rails/pull/38901,
this commit makes a small performance enhancement by iterating through
the ast once instead of twice when initializing a Mapping.

This stemmed from work to improve the boot time of an application with
3500+ routes. This patch only shaves off about 70ms from our boot time,
and about 25000 allocations, but every little bit counts!

Benchmark
---

```rb

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"

  git_source(:github) { |repo| "https://github.com/#{repo}.git" }

  # Activate the gem you are reporting the issue against.
  gem "rails", path: "/Users/daniel/Desktop/oss/rails/rails"
  gem "benchmark-ips"
  gem "benchmark-memory", require: "benchmark/memory"
end

require "action_controller/railtie"

class TestApp < Rails::Application
  config.root = __dir__
  config.hosts << "example.org"
  config.session_store :cookie_store, key: "cookie_store_key"
  secrets.secret_key_base = "secret_key_base"

  config.logger = Logger.new($stdout)
  Rails.logger = config.logger

  routes.draw do
    get("/*wildcard", to: "controller#index")
  end
end
```

With the benchmarking code inserted into Mapper#initialize:

```rb
after = -> {
  path_params = []
  wildcard_options = {}
  ast.each do |node|
    if node.symbol?
      path_params << node.to_sym
    elsif node.star? && formatted != false
      # Add a constraint for wildcard route to make it non-greedy and match the
      # optional format part of the route by default.
      wildcard_options[node.name.to_sym] ||= /.+?/
    end
  end

  wildcard_options.merge(options)
}

before = -> {
  path_params = ast.find_all(&:symbol?).map(&:to_sym)

  add_wildcard_options(options, formatted, ast)
}

puts "IPS"

Benchmark.ips do |x|
  x.report("before") { before.call }
  x.report("after") { after.call }
  x.compare!
end

puts "MEMORY"

Benchmark.memory do |x|
  x.report("before") { before.call }
  x.report("after") { after.call }
  x.compare!
end
```

The results are:

```
IPS
Warming up --------------------------------------
              before    14.352k i/100ms
               after    30.852k i/100ms
Calculating -------------------------------------
              before    135.675k (± 3.7%) i/s -    688.896k in   5.084368s
               after    288.126k (± 3.3%) i/s -      1.450M in   5.038072s

Comparison:
               after:   288126.4 i/s
              before:   135675.1 i/s - 2.12x  (± 0.00) slower

MEMORY
Calculating -------------------------------------
              before   360.000  memsize (     0.000  retained)
                         7.000  objects (     0.000  retained)
                         0.000  strings (     0.000  retained)
               after   200.000  memsize (     0.000  retained)
                         4.000  objects (     0.000  retained)
                         0.000  strings (     0.000  retained)

comparison:
               after:        200 allocated
              before:        360 allocated - 1.80x more  end
```

Fix minor typos in i18n docs [ci-skip]

Added documentation for _default option added to ActiveRecord::Enum [ci skip]

Fix enum losing attribute type cast.

Sendgrid, like Mailgun, only passes BCC recipients as a parameter in the original JSON payload.

This PR adds code to prepend the recipients from the Sendgrid payload to the raw_email under the X-Original-To header.

References #38738.

Simplify attribute type decoration

This would have made the correct implementation for
894ed87a more obvious.

Bugfix for Mime::Type::MimeTypeInvalid handling in ActionDispatch::DebugExceptions

Co-authored-by: NEugene Kenny <elkenny@gmail.com>

Avoid double time zone converter decoration when user-defined timestamp attribute with implicit type

If type is given as a symbol, it will lookup a fresh type object via
`Type.lookup`, but if type is omitted, `type_for_attribute` will lookup
the database type which is already decorated by `define_attribute`.

To avoid the double decoration, skip extra decoration if its type is
already decorated.

The internal attribute decoration is almost covered by the `attribute`
with block, we don't need to have much code and extra class attribute.

Using `decorate_matching_attribute_type` is overkill to do that.

Revert "Fix test_any in relations_test.rb, which was failing when relations_test.rb is run on its own (it passes when the entire suite is run). This is a hacky fix for a problem I didn't quite get to the bottom of, so I'd welcome a better solution..."

This reverts commit d6289aad.

`assert_queries` ignores "SCHEMA" queries by default since #36153.

In Active Record internal, `arel_table` is not directly used but
`arel_attribute` is used, since `arel_table` doesn't normalize an
attribute name as a string, and doesn't resolve attribute aliases.

For the above reason, `arel_attribute` should be used rather than
`arel_table`, but most people directly use `arel_table`, both
`arel_table` and `arel_attribute` are private API though.

Although I'd not recommend using private API, `arel_table` is actually
widely used, and it is also problematic for unscopeable queries and
hash-like relation merging friendly, as I explained at #39863.

To resolve the issue, this change moves Arel attribute normalization
(attribute name as a string, and attribute alias resolution) into
`arel_table`.

Ensure principle tasks go before finish_template

Document how exceptions are handled in instrumentation [ci skip]

fix typo in Active Job exceptions docs [ci skip]

Fix typos in active support docs [ci-skip]

Revert "Merge pull request #39613 from kamipo/where_with_custom_operator"

This reverts commit b8064500, reversing
changes made to 8714b359.

Reason: This is not approved from the core team yet...

Merge pull request #39829 from tgxworld/remove_protect_from_forgery_from_application_controller_template

Remove `protect_from_forgery` in rails plugin template.

Switch regex for delete_suffix in normalize_path

References #39367.