Merge pull request #15782 from sgrif/sg-column-defaults

Don't type cast the default on the column
Reconnect after possibly enabling hstore
Titling the model name in views generated by scaffold.
eg. rails g scaffold UserProfile will have in index.html.erb "Listing User Profiles"
rather than Listing user_profiles.
Merge pull request #15709 from zuhao/refactor_actionview_compiled_templates_test

Move cleanup into teardown, delete obsolete code.
Extract out with_env_tz helper method.

It’s used at so many places that extracting it out into a helper file
is worth doing.
Don't use `Column` for type casting in Relation calculations
Don't use column object when calculating type cast defaults

Moves towards removing type casting knowledge from the column entirely
Merge pull request #15799 from zuhao/refactor_activesupport_time_zone_test_helpers

Extract out with_env_tz helper method.
Don't use column object for type casting in `quoting`

We're never going to be able to use the attribute object here, however,
so let's just accept the ugly demeter violation here for now.

Remove test cases which were either redundant with other tests in the
file, or were actually testing the type objects (which are tested
elsewhere)
Don't rely on the column for type casting reflections
Merge pull request #15795 from amitsuryavanshi/master

Titling the model name in views generated by scaffold.
Added missing colon in asset manifest JSON.
Create custom errors page on ActionController guides

[ci skip]
this method is no longer being used
Remove unused block parameter from #gsub call in AM::MailHelper#block_format
Merge pull request #15812 from crankharder/remove_postgres_adapter_method

remove unused method from Postgresql::Adapter
Relpace `=~ Regexp.new str` with `.include? str` in AC::Base#_valid_action_name?

Because it is more natural way to test substring inclusion. Also, in
this particular case it is much faster.

In general, using `Regexp.new str` for such kind of things is dangerous.
The string must be escaped, unless you know what you're doing. Example:

    Regexp.new "\\" # HELLO WINDOWS
    # RegexpError: too short escape sequence: /\/

The right way to do this is escape the string

    Regexp.new Regexp.escape "\\"
    # => /\\/

Here is the benchmark showing how faster `include?` call is.

```
require 'benchmark/ips'

Benchmark.ips do |x|
  x.report('include?') { !"index".to_s.include? File::SEPARATOR }
  x.report('   !~   ') { "index" !~ Regexp.new(File::SEPARATOR) }
end

__END__
Calculating -------------------------------------
            include?     75754 i/100ms
               !~        21089 i/100ms
-------------------------------------------------
            include?  3172882.3 (±4.5%) i/s -   15832586 in   5.000659s
               !~      322918.8 (±8.6%) i/s -    1602764 in   4.999509s
```

Extra `.to_s` call is needed to handle the case when `action_name` is
`nil`. If it is omitted, some tests fail.
Further simplify `changed?` conditional for numeric types

`Type::Integer.new.type_cast('') # => nil`, we do not need a special
case to handle this, `nil => ''` already returns false. The only case we
need to handle is `0 => 'wibble'` should be changed, while `0 => '0'`
should not.
Add `logger.debug?` guard to `ActionMailer::LogSubscriber#process`

*TLDR*: The method is 4 times faster when log level is higher than DEBUG.
Also, the other two methods, `#deliver` and `#receive` have similar guard statements,
so this commit adds some symmetry to the code.

This is probably not the most critical part of ActionMailer in terms
of performance, but here are some benchmarks:

```
require 'benchmark/ips'
require 'action_mailer'

event = ActiveSupport::Notifications::Event.new(
            'process.action_mailer',
            Time.now,
            Time.now,
            'bf4e2b36ce085fd35b24',
            { mailer: "UserMailer", action: :welcome }
        )

ActionMailer::Base.logger = ActiveSupport::Logger.new '/dev/null'

subscriber = ActionMailer::LogSubscriber.new
def subscriber.process_with_guard(event)
  return unless logger.debug?
  mailer = event.payload[:mailer]
  action = event.payload[:action]
  debug("\n#{mailer}##{action}: processed outbound mail in #{event.duration.round(1)}ms")
end

Benchmark.ips do |r|
  ActionMailer::Base.logger.level = ::Logger::Severity::INFO
  r.report('no guard') { subscriber.process(event) }
  r.report('   guard') { subscriber.process_with_guard(event) }
end

__END__
Calculating -------------------------------------
            no guard      9640 i/100ms
               guard     38381 i/100ms
-------------------------------------------------
            no guard   169166.9 (±10.2%) i/s -     838680 in   5.007262s
               guard   728184.9 (±9.6%) i/s -    3607814 in   4.999218s
```

When log level is DEBUG, the _guarded_ method is a bit slower. This is a
good tradeoff for 4x improvement in production mode.

```
Benchmark.ips do |r|
  ActionMailer::Base.logger.level = ::Logger::Severity::DEBUG
  r.report('no guard') { subscriber.process(event) }
  r.report('   guard') { subscriber.process_with_guard(event) }
end

__END__
Calculating -------------------------------------
            no guard      4970 i/100ms
               guard      4564 i/100ms
-------------------------------------------------
            no guard    55617.4 (±3.5%) i/s -     278320 in   5.010523s
               guard    49452.1 (±5.6%) i/s -     251020 in   5.093358s

```
Merge pull request #15816 from DNNX/log-subscriber-add-debug-check

Add `logger.debug?` guard to `ActionMailer::LogSubscriber#process`