activerecord 6.0.0.beta1 on Ruby Gems

Active Support

Remove deprecated Module#reachable? method.
Rafael Mendonça França
Remove deprecated #acronym_regex method from Inflections.
Rafael Mendonça França
Fix String#safe_constantize throwing a LoadError for incorrectly cased constant references.
Keenan Brock
Preserve key order passed to ActiveSupport::CacheStore#fetch_multi.
fetch_multi(*names) now returns its results in the same order as the *names requested, rather than returning cache hits followed by cache misses.
Gannon McGibbon
If the same block is included multiple times for a Concern, an exception is no longer raised.
Mark J. Titorenko, Vlad Bokov
Fix bug where #to_options for ActiveSupport::HashWithIndifferentAccess
would not act as alias for #symbolize_keys.
Nick Weiland
Improve the logic that detects non-autoloaded constants.
Jan Habermann, Xavier Noria
Deprecate ActiveSupport::Multibyte::Unicode#pack_graphemes(array) and ActiveSuppport::Multibyte::Unicode#unpack_graphemes(string)
in favor of array.flatten.pack("U*") and string.scan(/\X/).map(&:codepoints), respectively.
Francesco Rodríguez
Deprecate ActiveSupport::Multibyte::Chars.consumes? in favor of String#is_utf8?.
Francesco Rodríguez
Fix duration being rounded to a full second.
```
  time = DateTime.parse("2018-1-1")
  time += 0.51.seconds
```
Will now correctly add 0.51 second and not 1 full second.
Edouard Chin
Deprecate ActiveSupport::Multibyte::Unicode#normalize and ActiveSuppport::Multibyte::Chars#normalize
in favor of String#unicode_normalize
Francesco Rodríguez
Deprecate ActiveSupport::Multibyte::Unicode#downcase/upcase/swapcase in favor of
String#downcase/upcase/swapcase.
Francesco Rodríguez
Add ActiveSupport::ParameterFilter.
Yoshiyuki Kinjo
Rename Module#parent, Module#parents, and Module#parent_name to
module_parent, module_parents, and module_parent_name.
Gannon McGibbon
Deprecate the use of LoggerSilence in favor of ActiveSupport::LoggerSilence
Edouard Chin
Deprecate using negative limits in String#first and String#last.
Gannon McGibbon, Eric Turner
Fix bug where #without for ActiveSupport::HashWithIndifferentAccess would fail
with symbol arguments
Abraham Chan
Treat #delete_prefix, #delete_suffix and #unicode_normalize results as non-html_safe.
Ensure safety of arguments for #insert, #[]= and #replace calls on html_safe Strings.
Janosch Müller
Changed ActiveSupport::TaggedLogging.new to return a new logger instance instead
of mutating the one received as parameter.
Thierry Joyal
Define unfreeze_time as an alias of travel_back in ActiveSupport::Testing::TimeHelpers.
The alias is provided for symmetry with freeze_time.
Ryan Davidson

Add support for tracing constant autoloads. Just throw

ActiveSupport::Dependencies.logger = Rails.logger
ActiveSupport::Dependencies.verbose = true

in an initializer.

Xavier Noria

Maintain html_safe? on html_safe strings when sliced.

string = "<div>test</div>".html_safe
string[-1..1].html_safe? # => true

Elom Gomez, Yumin Wong

Add Array#extract!.
The method removes and returns the elements for which the block returns a true value.
If no block is given, an Enumerator is returned instead.
```
numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
odd_numbers = numbers.extract! { |number| number.odd? } # => [1, 3, 5, 7, 9]
numbers # => [0, 2, 4, 6, 8]
```
bogdanvlviv

Support not to cache nil for ActiveSupport::Cache#fetch.

cache.fetch('bar', skip_nil: true) { nil }
cache.exist?('bar') # => false

Martin Hong

Add "event object" support to the notification system.
Before this change, end users were forced to create hand made artisanal
event objects on their own, like this:

ActiveSupport::Notifications.subscribe('wait') do |*args|
  @event = ActiveSupport::Notifications::Event.new(*args)
end

ActiveSupport::Notifications.instrument('wait') do
  sleep 1
end

@event.duration # => 1000.138

After this change, if the block passed to subscribe only takes one
parameter, the framework will yield an event object to the block. Now
end users are no longer required to make their own:

ActiveSupport::Notifications.subscribe('wait') do |event|
  @event = event
end

ActiveSupport::Notifications.instrument('wait') do
  sleep 1
end

p @event.allocations # => 7
p @event.cpu_time    # => 0.256
p @event.idle_time   # => 1003.2399

Now you can enjoy event objects without making them yourself. Neat!

Aaron "t.lo" Patterson

Add cpu_time, idle_time, and allocations to Event.
Eileen M. Uchitelle, Aaron Patterson
RedisCacheStore: support key expiry in increment/decrement.
Pass :expires_in to #increment and #decrement to set a Redis EXPIRE on the key.
If the key is already set to expire, RedisCacheStore won't extend its expiry.
```
Rails.cache.increment("some_key", 1, expires_in: 2.minutes)
```
Jason Lee
Allow Range#=== and Range#cover? on Range.
Range#cover? can now accept a range argument like Range#include? and
Range#===. Range#=== works correctly on Ruby 2.6. Range#include? is moved
into a new file, with these two methods.
Requiring active_support/core_ext/range/include_range is now deprecated.
Use require "active_support/core_ext/range/compare_range" instead.
utilum
Add index_with to Enumerable.
Allows creating a hash from an enumerable with the value from a passed block
or a default argument.
```
%i( title body ).index_with { |attr| post.public_send(attr) }
# => { title: "hey", body: "what's up?" }

%i( title body ).index_with(nil)
# => { title: nil, body: nil }
```
Closely linked with index_by, which creates a hash where the keys are extracted from a block.
Kasper Timm Hansen
Fix bug where ActiveSupport::Timezone.all would fail when tzinfo data for
any timezone defined in ActiveSupport::TimeZone::MAPPING is missing.
Dominik Sander
Redis cache store: delete_matched no longer blocks the Redis server.
(Switches from evaled Lua to a batched SCAN + DEL loop.)
Gleb Mazovetskiy
Fix bug where ActiveSupport::Cache will massively inflate the storage
size when compression is enabled (which is true by default). This patch
does not attempt to repair existing data: please manually flush the cache
to clear out the problematic entries.
Godfrey Chan

Fix bug where URI.unescape would fail with mixed Unicode/escaped character input:

URI.unescape("\xe3\x83\x90")  # => "バ"
URI.unescape("%E3%83%90")  # => "バ"
URI.unescape("\xe3\x83\x90%E3%83%90")  # => Encoding::CompatibilityError

Ashe Connor, Aaron Patterson

Add before? and after? methods to Date, DateTime,
Time, and TimeWithZone.
Nick Holden

ActiveSupport::Inflector#ordinal and ActiveSupport::Inflector#ordinalize now support
translations through I18n.

# locale/fr.rb

{
  fr: {
    number: {
      nth: {
        ordinals: lambda do |_key, number:, **_options|
          if number.to_i.abs == 1
            'er'
          else
            'e'
          end
        end,

        ordinalized: lambda do |_key, number:, **_options|
          "#{number}#{ActiveSupport::Inflector.ordinal(number)}"
        end
      }
    }
  }
}

Christian Blais

Add :private option to ActiveSupport's Module#delegate
in order to delegate methods as private:

class User < ActiveRecord::Base
  has_one :profile
  delegate :date_of_birth, to: :profile, private: true

  def age
    Date.today.year - date_of_birth.year
  end
end

# User.new.age  # => 29
# User.new.date_of_birth
# => NoMethodError: private method `date_of_birth' called for #<User:0x00000008221340>

Tomas Valent

String#truncate_bytes to truncate a string to a maximum bytesize without
breaking multibyte characters or grapheme clusters like 👩‍👩‍👦‍👦.
Jeremy Daer

String#strip_heredoc preserves frozenness.

"foo".freeze.strip_heredoc.frozen?  # => true

Fixes that frozen string literals would inadvertently become unfrozen:

# frozen_string_literal: true

foo = <<-MSG.strip_heredoc
  la la la
MSG

foo.frozen?  # => false !??

Jeremy Daer

Rails 6 requires Ruby 2.5.0 or newer.
Jeremy Daer, Kasper Timm Hansen
Adds parallel testing to Rails.
Parallelize your test suite with forked processes or threads.
Eileen M. Uchitelle, Aaron Patterson

Active Model

Add ActiveModel::Errors#of_kind?.
bogdanvlviv, Rafael Mendonça França
Fix numericality equality validation of BigDecimal and Float
by casting to BigDecimal on both ends of the validation.
Gannon McGibbon
Add #slice! method to ActiveModel::Errors.
Daniel López Prat
Fix numericality validator to still use value before type cast except Active Record.
Fixes #33651, #33686.
Ryuta Kamizono

Fix ActiveModel::Serializers::JSON#as_json method for timestamps.

Before:

contact = Contact.new(created_at: Time.utc(2006, 8, 1))
contact.as_json["created_at"] # => 2006-08-01 00:00:00 UTC

After:

contact = Contact.new(created_at: Time.utc(2006, 8, 1))
contact.as_json["created_at"] # => "2006-08-01T00:00:00.000Z"

Bogdan Gusiev

Allows configurable attribute name for #has_secure_password. This
still defaults to an attribute named 'password', causing no breaking
change. There is a new method #authenticate_XXX where XXX is the
configured attribute name, making the existing #authenticate now an
alias for this when the attribute is the default 'password'.
Example:
```
class User < ActiveRecord::Base
  has_secure_password :recovery_password, validations: false
end

user = User.new()
user.recovery_password = "42password"
user.recovery_password_digest # => "$2a$04$iOfhwahFymCs5weB3BNH/uX..."
user.authenticate_recovery_password('42password') # => user
```
Unathi Chonco
Add config.active_model.i18n_full_message in order to control whether
the full_message error format can be overridden at the attribute or model
level in the locale files. This is false by default.
Martin Larochelle
Rails 6 requires Ruby 2.5.0 or newer.
Jeremy Daer, Kasper Timm Hansen

Active Record

Remove deprecated #set_state from the transaction object.
Rafael Mendonça França
Remove deprecated #supports_statement_cache? from the database adapters.
Rafael Mendonça França
Remove deprecated #insert_fixtures from the database adapters.
Rafael Mendonça França
Remove deprecated ActiveRecord::ConnectionAdapters::SQLite3Adapter#valid_alter_table_type?.
Rafael Mendonça França
Do not allow passing the column name to sum when a block is passed.
Rafael Mendonça França
Do not allow passing the column name to count when a block is passed.
Rafael Mendonça França
Remove delegation of missing methods in a relation to arel.
Rafael Mendonça França
Remove delegation of missing methods in a relation to private methods of the class.
Rafael Mendonça França
Deprecate config.activerecord.sqlite3.represent_boolean_as_integer.
Rafael Mendonça França
Change SQLite3Adapter to always represent boolean values as integers.
Rafael Mendonça França
Remove ability to specify a timestamp name for #cache_key.
Rafael Mendonça França
Remove deprecated ActiveRecord::Migrator.migrations_path=.
Rafael Mendonça França
Remove deprecated expand_hash_conditions_for_aggregates.
Rafael Mendonça França
Set polymorphic type column to NULL on dependent: :nullify strategy.
On polymorphic associations both the foreign key and the foreign type columns will be set to NULL.
Laerti Papa
Allow permitted instance of ActionController::Parameters as argument of ActiveRecord::Relation#exists?.
Gannon McGibbon
Add support for endless ranges introduces in Ruby 2.6.
Greg Navis
Deprecate passing migrations_paths to connection.assume_migrated_upto_version.
Ryuta Kamizono
MySQL: ROW_FORMAT=DYNAMIC create table option by default.
Since MySQL 5.7.9, the innodb_default_row_format option defines the default row
format for InnoDB tables. The default setting is DYNAMIC.
The row format is required for indexing on varchar(255) with utf8mb4 columns.
Ryuta Kamizono
Fix join table column quoting with SQLite.
Gannon McGibbon
Allow disabling scopes generated by ActiveRecord.enum.
Alfred Dominic
Ensure that delete_all on collection proxy returns affected count.
Ryuta Kamizono
Reset scope after delete on collection association to clear stale offsets of removed records.
Gannon McGibbon
Add the ability to prevent writes to a database for the duration of a block.
Allows the application to prevent writes to a database. This can be useful when
you're building out multiple databases and want to make sure you're not sending
writes when you want a read.
If while_preventing_writes is called and the query is considered a write
query the database will raise an exception regardless of whether the database
user is able to write.
This is not meant to be a catch-all for write queries but rather a way to enforce
read-only queries without opening a second connection. One purpose of this is to
catch accidental writes, not all writes.
Eileen M. Uchitelle
Allow aliased attributes to be used in #update_columns and #update.
Gannon McGibbon
Allow spaces in postgres table names.
Fixes issue where "user post" is misinterpreted as ""user"."post"" when quoting table names with the postgres adapter.
Gannon McGibbon

Cached columns_hash fields should be excluded from ResultSet#column_types

PR #34528 addresses the inconsistent behaviour when attribute is defined for an ignored column. The following test
was passing for SQLite and MySQL, but failed for PostgreSQL:

class DeveloperName < ActiveRecord::Type::String
  def deserialize(value)
    "Developer: #{value}"
  end
end

class AttributedDeveloper < ActiveRecord::Base
  self.table_name = "developers"

  attribute :name, DeveloperName.new

  self.ignored_columns += ["name"]
end

developer = AttributedDeveloper.create
developer.update_column :name, "name"

loaded_developer = AttributedDeveloper.where(id: developer.id).select("*").first
puts loaded_developer.name # should be "Developer: name" but it's just "name"

Dmitry Tsepelev

Make the implicit order column configurable.
When calling ordered finder methods such as +first+ or +last+ without an
explicit order clause, ActiveRecord sorts records by primary key. This can
result in unpredictable and surprising behaviour when the primary key is
not an auto-incrementing integer, for example when it's a UUID. This change
makes it possible to override the column used for implicit ordering such
that +first+ and +last+ will return more predictable results.
Example:
```
class Project < ActiveRecord::Base
  self.implicit_order_column = "created_at"
end
```
Tekin Suleyman
Bump minimum PostgreSQL version to 9.3.
Yasuo Honda
Values of enum are frozen, raising an error when attempting to modify them.
Emmanuel Byrd
Move ActiveRecord::StatementInvalid SQL to error property and include binds as separate error property.
ActiveRecord::ConnectionAdapters::AbstractAdapter#translate_exception_class now requires binds to be passed as the last argument.
ActiveRecord::ConnectionAdapters::AbstractAdapter#translate_exception now requires message, sql, and binds to be passed as keyword arguments.
Subclasses of ActiveRecord::StatementInvalid must now provide sql: and binds: arguments to super.
Example:
```
class MySubclassedError < ActiveRecord::StatementInvalid
  def initialize(message, sql:, binds:)
    super(message, sql: sql, binds: binds)
  end
end
```
Gannon McGibbon
Add an :if_not_exists option to create_table.
Example:
```
create_table :posts, if_not_exists: true do |t|
  t.string :title
end
```
That would execute:
```
CREATE TABLE IF NOT EXISTS posts (
  ...
)
```
If the table already exists, if_not_exists: false (the default) raises an
exception whereas if_not_exists: true does nothing.
fatkodima, Stefan Kanev
Defining an Enum as a Hash with blank key, or as an Array with a blank value, now raises an ArgumentError.
Christophe Maximin
Adds support for multiple databases to rails db:schema:cache:dump and rails db:schema:cache:clear.
Gannon McGibbon
update_columns now correctly raises ActiveModel::MissingAttributeError
if the attribute does not exist.
Sean Griffin

Add support for hash and url configs in database hash of ActiveRecord::Base.connected_to.

User.connected_to(database: { writing: "postgres://foo" }) do
  User.create!(name: "Gannon")
end

config = { "adapter" => "sqlite3", "database" => "db/readonly.sqlite3" }
User.connected_to(database: { reading: config }) do
  User.count
end

Gannon McGibbon

Support default expression for MySQL.
MySQL 8.0.13 and higher supports default value to be a function or expression.
https://dev.mysql.com/doc/refman/8.0/en/create-table.html
Ryuta Kamizono
Support expression indexes for MySQL.
MySQL 8.0.13 and higher supports functional key parts that index
expression values rather than column or column prefix values.
https://dev.mysql.com/doc/refman/8.0/en/create-index.html
Ryuta Kamizono
Fix collection cache key with limit and custom select to avoid ambiguous timestamp column error.
Fixes #33056.
Federico Martinez

Add basic API for connection switching to support multiple databases.

Adds a connects_to method for models to connect to multiple databases. Example:

class AnimalsModel < ApplicationRecord
  self.abstract_class = true

  connects_to database: { writing: :animals_primary, reading: :animals_replica }
end

class Dog < AnimalsModel
  # connected to both the animals_primary db for writing and the animals_replica for reading
end

Adds a connected_to block method for switching connection roles or connecting to
a database that the model didn't connect to. Connecting to the database in this block is
useful when you have another defined connection, for example slow_replica that you don't
want to connect to by default but need in the console, or a specific code block.

ActiveRecord::Base.connected_to(role: :reading) do
  Dog.first # finds dog from replica connected to AnimalsBase
  Book.first # doesn't have a reading connection, will raise an error
end

ActiveRecord::Base.connected_to(database: :slow_replica) do
  SlowReplicaModel.first # if the db config has a slow_replica configuration this will be used to do the lookup, otherwise this will throw an exception
end

Eileen M. Uchitelle

Enum raises on invalid definition values
When defining a Hash enum it can be easy to use [] instead of {}. This
commit checks that only valid definition values are provided, those can
be a Hash, an array of Symbols or an array of Strings. Otherwise it
raises an ArgumentError.
Fixes #33961
Alberto Almagro

Reloading associations now clears the Query Cache like Persistence#reload does.

class Post < ActiveRecord::Base
  has_one :category
  belongs_to :author
  has_many :comments
end

# Each of the following will now clear the query cache.
post.reload_category
post.reload_author
post.comments.reload

Christophe Maximin

Added index option for change_table migration helpers.
With this change you can create indexes while adding new
columns into the existing tables.
Example:
```
change_table(:languages) do |t|
  t.string :country_code, index: true
end
```
Mehmet Emin İNAÇ
Fix transaction reverting for migrations.
Before: Commands inside a transaction in a reverted migration ran uninverted.
Now: This change fixes that by reverting commands inside transaction block.
fatkodima, David Verhasselt
Raise an error instead of scanning the filesystem root when fixture_path is blank.
Gannon McGibbon, Max Albrecht
Allow ActiveRecord::Base.configurations= to be set with a symbolized hash.
Gannon McGibbon
Don't update counter cache unless the record is actually saved.
Fixes #31493, #33113, #33117.
Ryuta Kamizono
Deprecate ActiveRecord::Result#to_hash in favor of ActiveRecord::Result#to_a.
Gannon McGibbon, Kevin Cheng

SQLite3 adapter supports expression indexes.

create_table :users do |t|
  t.string :email
end

add_index :users, 'lower(email)', name: 'index_users_on_email', unique: true

Gray Kemmey

Allow subclasses to redefine autosave callbacks for associated records.
Fixes #33305.
Andrey Subbota
Bump minimum MySQL version to 5.5.8.
Yasuo Honda
Use MySQL utf8mb4 character set by default.
utf8mb4 character set with 4-Byte encoding supports supplementary characters including emoji.
The previous default 3-Byte encoding character set utf8 is not enough to support them.
Yasuo Honda
Fix duplicated record creation when using nested attributes with create_with.
Darwin Wu

Configuration item config.filter_parameters could also filter out
sensitive values of database columns when call #inspect.
We also added ActiveRecord::Base::filter_attributes/= in order to
specify sensitive attributes to specific model.

Rails.application.config.filter_parameters += [:credit_card_number, /phone/]
Account.last.inspect # => #<Account id: 123, name: "DHH", credit_card_number: [FILTERED], telephone_number: [FILTERED] ...>
SecureAccount.filter_attributes += [:name]
SecureAccount.last.inspect # => #<SecureAccount id: 42, name: [FILTERED], credit_card_number: [FILTERED] ...>

Zhang Kang, Yoshiyuki Kinjo

Deprecate column_name_length, table_name_length, columns_per_table,
indexes_per_table, columns_per_multicolumn_index, sql_query_length,
and joins_per_query methods in DatabaseLimits.
Ryuta Kamizono
ActiveRecord::Base.configurations now returns an object.
ActiveRecord::Base.configurations used to return a hash, but this
is an inflexible data model. In order to improve multiple-database
handling in Rails, we've changed this to return an object. Some methods
are provided to make the object behave hash-like in order to ease the
transition process. Since most applications don't manipulate the hash
we've decided to add backwards-compatible functionality that will throw
a deprecation warning if used, however calling ActiveRecord::Base.configurations
will use the new version internally and externally.
For example, the following database.yml:
```
development:
  adapter: sqlite3
  database: db/development.sqlite3
```
Used to become a hash:
```
{ "development" => { "adapter" => "sqlite3", "database" => "db/development.sqlite3" } }
```
Is now converted into the following object:
```
#<ActiveRecord::DatabaseConfigurations:0x00007fd1acbdf800 @configurations=[
  #<ActiveRecord::DatabaseConfigurations::HashConfig:0x00007fd1acbded10 @env_name="development",
    @spec_name="primary", @config={"adapter"=>"sqlite3", "database"=>"db/development.sqlite3"}>
  ]
```
Iterating over the database configurations has also changed. Instead of
calling hash methods on the configurations hash directly, a new method configs_for has
been provided that allows you to select the correct configuration. env_name, and
spec_name arguments are optional. For example these return an array of
database config objects for the requested environment and a single database config object
will be returned for the requested environment and specification name respectively.
```
ActiveRecord::Base.configurations.configs_for(env_name: "development")
ActiveRecord::Base.configurations.configs_for(env_name: "development", spec_name: "primary")
```
Eileen M. Uchitelle, Aaron Patterson
Add database configuration to disable advisory locks.
```
production:
  adapter: postgresql
  advisory_locks: false
```
Guo Xiang
SQLite3 adapter alter_table method restores foreign keys.
Yasuo Honda
Allow :to_table option to invert_remove_foreign_key.
Example:
remove_foreign_key :accounts, to_table: :owners
Nikolay Epifanov, Rich Chen
Add environment & load_config dependency to bin/rake db:seed to enable
seed load in environments without Rails and custom DB configuration
Tobias Bielohlawek
Fix default value for mysql time types with specified precision.
Nikolay Kondratyev
Fix touch option to behave consistently with Persistence#touch method.
Ryuta Kamizono
Migrations raise when duplicate column definition.
Fixes #33024.
Federico Martinez
Bump minimum SQLite version to 3.8
Yasuo Honda
Fix parent record should not get saved with duplicate children records.
Fixes #32940.
Santosh Wadghule
Fix logic on disabling commit callbacks so they are not called unexpectedly when errors occur.
Brian Durand
Ensure Associations::CollectionAssociation#size and Associations::CollectionAssociation#empty?
use loaded association ids if present.
Graham Turner
Add support to preload associations of polymorphic associations when not all the records have the requested associations.
Dana Sherson

Add touch_all method to ActiveRecord::Relation.

Example:

Person.where(name: "David").touch_all(time: Time.new(2020, 5, 16, 0, 0, 0))

fatkodima, duggiefresh

Add ActiveRecord::Base.base_class? predicate.
Bogdan Gusiev
Add custom prefix/suffix options to ActiveRecord::Store.store_accessor.
Tan Huynh, Yukio Mizuta
Rails 6 requires Ruby 2.5.0 or newer.
Jeremy Daer, Kasper Timm Hansen
Deprecate update_attributes/! in favor of update/!.
Eddie Lebow
Add ActiveRecord::Base.create_or_find_by/! to deal with the SELECT/INSERT race condition in
ActiveRecord::Base.find_or_create_by/! by leaning on unique constraints in the database.
DHH
Add Relation#pick as short-hand for single-value plucks.
DHH

Action View

Remove deprecated image_alt helper.
Rafael Mendonça França
Fix the need of #protect_against_forgery? method defined in
ActionView::Base subclasses. This prevents the use of forms and buttons.
Genadi Samokovarov
Fix UJS permanently showing disabled text in a[data-remote][data-disable-with] elements within forms.
Fixes #33889
Wolfgang Hobmaier
Prevent non-primary mouse keys from triggering Rails UJS click handlers.
Firefox fires click events even if the click was triggered by non-primary mouse keys such as right- or scroll-wheel-clicks.
For example, right-clicking a link such as the one described below (with an underlying ajax request registered on click) should not cause that request to occur.
```
<%= link_to 'Remote', remote_path, class: 'remote', remote: true, data: { type: :json } %>
```
Fixes #34541
Wolfgang Hobmaier
Prevent ActionView::TextHelper#word_wrap from unexpectedly stripping white space from the left side of lines.
For example, given input like this:
```
    This is a paragraph with an initial indent,
followed by additional lines that are not indented,
and finally terminated with a blockquote:
  "A pithy saying"
```
Calling word_wrap should not trim the indents on the first and last lines.
Fixes #34487
Lyle Mullican

Add allocations to template rendering instrumentation.

Adds the allocations for template and partial rendering to the server output on render.

  Rendered posts/_form.html.erb (Duration: 7.1ms | Allocations: 6004)
  Rendered posts/new.html.erb within layouts/application (Duration: 8.3ms | Allocations: 6654)
Completed 200 OK in 858ms (Views: 848.4ms | ActiveRecord: 0.4ms | Allocations: 1539564)

Eileen M. Uchitelle, Aaron Patterson

Respect the only_path option passed to url_for when the options are passed in as an array
Fixes #33237.
Joel Ambass
Deprecate calling private model methods from view helpers.
For example, in methods like options_from_collection_for_select
and collection_select it is possible to call private methods from
the objects used.
Fixes #33546.
Ana María Martínez Gómez
Fix issue with button_to's to_form_params
button_to was throwing exception when invoked with params hash that
contains symbol and string keys. The reason for the exception was that
to_form_params was comparing the given symbol and string keys.
The issue is fixed by turning all keys to strings inside
to_form_params before comparing them.
Georgi Georgiev

Mark arrays of translations as trusted safe by using the _html suffix.

Example:

en:
  foo_html:
    - "One"
    - "<strong>Two</strong>"
    - "Three &#128075; &#128578;"

Juan Broullon

Add year_format option to date_select tag. This option makes it possible to customize year
names. Lambda should be passed to use this option.

Example:

date_select('user_birthday', '', start_year: 1998, end_year: 2000, year_format: ->year { "Heisei #{year - 1988}" })

The HTML produced:

<select id="user_birthday__1i" name="user_birthday[(1i)]">
<option value="1998">Heisei 10</option>
<option value="1999">Heisei 11</option>
<option value="2000">Heisei 12</option>
</select>
/* The rest is omitted */

Koki Ryu

Fix JavaScript views rendering does not work with Firefox when using
Content Security Policy.
Fixes #32577.
Yuji Yaginuma
Add the nonce: true option for javascript_include_tag helper to
support automatic nonce generation for Content Security Policy.
Works the same way as javascript_tag nonce: true does.
Yaroslav Markin
Remove ActionView::Helpers::RecordTagHelper.
Yoshiyuki Hirano
Disable ActionView::Template finalizers in test environment.
Template finalization can be expensive in large view test suites.
Add a configuration option,
action_view.finalize_compiled_template_methods, and turn it off in
the test environment.
Simon Coffey

Extract the confirm call in its own, overridable method in rails_ujs.

Example:

Rails.confirm = function(message, element) {
  return (my_bootstrap_modal_confirm(message));
}

Mathieu Mahé

Enable select tag helper to mark prompt option as selected and/or disabled for required
field.

Example:

select :post,
       :category,
       ["lifestyle", "programming", "spiritual"],
       { selected: "", disabled: "", prompt: "Choose one" },
       { required: true }

Placeholder option would be selected and disabled.

The HTML produced:

<select required="required" name="post[category]" id="post_category">
<option disabled="disabled" selected="selected" value="">Choose one</option>
<option value="lifestyle">lifestyle</option>
<option value="programming">programming</option>
<option value="spiritual">spiritual</option></select>

Sergey Prikhodko

Don't enforce UTF-8 by default.
With the disabling of TLS 1.0 by most major websites, continuing to run
IE8 or lower becomes increasingly difficult so default to not enforcing
UTF-8 encoding as it's not relevant to other browsers.
Andrew White
Change translation key of submit_tag from module_name_class_name to module_name/class_name.
Rui Onodera
Rails 6 requires Ruby 2.5.0 or newer.
Jeremy Daer, Kasper Timm Hansen

Action Pack

Remove deprecated fragment_cache_key helper in favor of combined_fragment_cache_key.
Rafael Mendonça França
Remove deprecated methods in ActionDispatch::TestResponse.
#success?, missing? and error? were deprecated in Rails 5.2 in favor of
#successful?, not_found? and server_error?.
Rafael Mendonça França
Ensure external redirects are explicitly allowed
Add fallback_location and allow_other_host options to redirect_to.
Gannon McGibbon
Introduce ActionDispatch::HostAuthorization
This is a new middleware that guards against DNS rebinding attacks by
white-listing the allowed hosts a request can be made to.
Each host is checked with the case operator (#===) to support RegExp,
Proc, IPAddr and custom objects as host allowances.
Genadi Samokovarov

Allow using parsed_body in ActionController::TestCase.

In addition to ActionDispatch::IntegrationTest, allow using
parsed_body in ActionController::TestCase:

class SomeControllerTest < ActionController::TestCase
  def test_some_action
    post :action, body: { foo: 'bar' }
    assert_equal({ "foo" => "bar" }, response.parsed_body)
  end
end

Fixes #34676.

Tobias Bühlmann

Raise an error on root route naming conflicts.
Raises an ArgumentError when multiple root routes are defined in the
same context instead of assigning nil names to subsequent roots.
Gannon McGibbon

Allow rescue from parameter parse errors:

rescue_from ActionDispatch::Http::Parameters::ParseError do
  head :unauthorized
end

Gannon McGibbon, Josh Cheek

Reset Capybara sessions if failed system test screenshot raising an exception.
Reset Capybara sessions if take_failed_screenshot raise exception
in system test after_teardown.
Maxim Perepelitsa
Use request object for context if there's no controller
There is no controller instance when using a redirect route or a
mounted rack application so pass the request object as the context
when resolving dynamic CSP sources in this scenario.
Fixes #34200.
Andrew White
Apply mapping to symbols returned from dynamic CSP sources
Previously if a dynamic source returned a symbol such as :self it
would be converted to a string implicity, e.g:
```
policy.default_src -> { :self }
```
would generate the header:
```
Content-Security-Policy: default-src self
```
and now it generates:
```
Content-Security-Policy: default-src 'self'
```
Andrew White
Add ActionController::Parameters#each_value.
Lukáš Zapletal
Deprecate ActionDispatch::Http::ParameterFilter in favor of ActiveSupport::ParameterFilter.
Yoshiyuki Kinjo
Encode Content-Disposition filenames on send_data and send_file.
Previously, send_data 'data', filename: "\u{3042}.txt" sends
"filename=\"\u{3042}.txt\"" as Content-Disposition and it can be
garbled.
Now it follows RFC 2231 and
RFC 5987 and sends
"filename=\"%3F.txt\"; filename*=UTF-8''%E3%81%82.txt".
Most browsers can find filename correctly and old browsers fallback to ASCII
converted name.
Fumiaki Matsushima
Expose ActionController::Parameters#each_key which allows iterating over
keys without allocating an array.
Richard Schneeman
Purpose metadata for signed/encrypted cookies.
Rails can now thwart attacks that attempt to copy signed/encrypted value
of a cookie and use it as the value of another cookie.
It does so by stashing the cookie-name in the purpose field which is
then signed/encrypted along with the cookie value. Then, on a server-side
read, we verify the cookie-names and discard any attacked cookies.
Enable action_dispatch.use_cookies_with_metadata to use this feature, which
writes cookies with the new purpose and expiry metadata embedded.
Assain Jaleel
Raises ActionController::RespondToMismatchError with confliciting respond_to invocations.
respond_to can match multiple types and lead to undefined behavior when
multiple invocations are made and the types do not match:
```
respond_to do |outer_type|
  outer_type.js do
    respond_to do |inner_type|
      inner_type.html { render body: "HTML" }
    end
  end
end
```
Patrick Toomey
ActionDispatch::Http::UploadedFile now delegates to_path to its tempfile.
This allows uploaded file objects to be passed directly to File.read
without raising a TypeError:
```
uploaded_file = ActionDispatch::Http::UploadedFile.new(tempfile: tmp_file)
File.read(uploaded_file)
```
Aaron Kromer
Pass along arguments to underlying get method in follow_redirect!.
Now all arguments passed to follow_redirect! are passed to the underlying
get method. This for example allows to set custom headers for the
redirection request to the server.
```
follow_redirect!(params: { foo: :bar })
```
Remo Fritzsche
Introduce a new error page to when the implicit render page is accessed in the browser.
Now instead of showing an error page that with exception and backtraces we now show only
one informative page.
Vinicius Stock
Introduce ActionDispatch::DebugExceptions.register_interceptor.
Exception aware plugin authors can use the newly introduced
.register_interceptor method to get the processed exception, instead of
monkey patching DebugExceptions.
```
ActionDispatch::DebugExceptions.register_interceptor do |request, exception|
  HypoteticalPlugin.capture_exception(request, exception)
end
```
Genadi Samokovarov
Output only one Content-Security-Policy nonce header value per request.
Fixes #32597.
Andrey Novikov, Andrew White
Move default headers configuration into their own module that can be included in controllers.
Kevin Deisz
Add method dig to session.
claudiob, Takumi Shotoku
Controller level force_ssl has been deprecated in favor of
config.force_ssl.
Derek Prior
Rails 6 requires Ruby 2.5.0 or newer.
Jeremy Daer, Kasper Timm Hansen

Active Job

Return false instead of the job instance when enqueue is aborted.
This will be the behavior in Rails 6.1 but it can be controlled now with
config.active_job.return_false_on_aborted_enqueue.
Kir Shatrov
Keep executions for each specific declaration
Each retry_on declaration has now its own specific executions counter. Before it was
shared between all executions of a job.
Alberto Almagro
Allow all assertion helpers that have a only and except keyword to accept
Procs.
Edouard Chin
Restore HashWithIndifferentAccess support to ActiveJob::Arguments.deserialize.
Gannon McGibbon
Include deserialized arguments in job instances returned from
assert_enqueued_with and assert_performed_with
Alan Wu
Allow assert_enqueued_with/assert_performed_with methods to accept
a proc for the args argument. This is useful to check if only a subset of arguments
matches your expectations.
Edouard Chin
ActionDispatch::IntegrationTest includes ActiveJob::TestHelper module by default.
Ricardo Díaz
Added enqueue_retry.active_job, retry_stopped.active_job, and discard.active_job hooks.
steves
Allow assert_performed_with to be called without a block.
bogdanvlviv
Execution of assert_performed_jobs, and assert_no_performed_jobs
without a block should respect passed :except, :only, and :queue options.
bogdanvlviv
Allow :queue option to job assertions and helpers.
bogdanvlviv
Allow perform_enqueued_jobs to be called without a block.
Performs all of the jobs that have been enqueued up to this point in the test.
Kevin Deisz
Move enqueue/enqueue_at notifications to an around callback.
Improves timing accuracy over the old after callback by including
time spent writing to the adapter's IO implementation.
Zach Kemp

Allow call assert_enqueued_with with no block.

Example:

def test_assert_enqueued_with
  MyJob.perform_later(1,2,3)
  assert_enqueued_with(job: MyJob, args: [1,2,3], queue: 'low')

  MyJob.set(wait_until: Date.tomorrow.noon).perform_later
  assert_enqueued_with(job: MyJob, at: Date.tomorrow.noon)
end

bogdanvlviv

Allow passing multiple exceptions to retry_on, and discard_on.
George Claghorn
Pass the error instance as the second parameter of block executed by discard_on.
Fixes #32853.
Yuji Yaginuma
Remove support for Qu gem.
Reasons are that the Qu gem wasn't compatible since Rails 5.1,
gem development was stopped in 2014 and maintainers have
confirmed its demise. See issue #32273
Alberto Almagro
Add support for timezones to Active Job.
Record what was the current timezone in effect when the job was
enqueued and then restore when the job is executed in same way
that the current locale is recorded and restored.
Andrew White
Rails 6 requires Ruby 2.5.0 or newer.
Jeremy Daer, Kasper Timm Hansen
Add support to define custom argument serializers.
Evgenii Pecherkin, Rafael Mendonça França

Action Mailer

Deprecate ActionMailer::Base.receive in favor of Action Mailbox.
George Claghorn
Add MailDeliveryJob for delivering both regular and parameterized mail. Deprecate using DeliveryJob and Parameterized::DeliveryJob.
Gannon McGibbon
Fix ActionMailer assertions not working when a Mail defines
a custom delivery job class
Edouard Chin
Mails with multipart format blocks with implicit render now also check for
a template name in options hash instead of only using the action name.
Marcus Ilgner
ActionDispatch::IntegrationTest includes ActionMailer::TestHelper module by default.
Ricardo Díaz
Add perform_deliveries to a payload of deliver.action_mailer notification.
Yoshiyuki Kinjo
Change delivery logging message when perform_deliveries is false.
Yoshiyuki Kinjo

Allow call assert_enqueued_email_with with no block.

Example:

def test_email
  ContactMailer.welcome.deliver_later
  assert_enqueued_email_with ContactMailer, :welcome
end

def test_email_with_arguments
  ContactMailer.welcome("Hello", "Goodbye").deliver_later
  assert_enqueued_email_with ContactMailer, :welcome, args: ["Hello", "Goodbye"]
end

bogdanvlviv

Ensure mail gem is eager autoloaded when eager load is true to prevent thread deadlocks.
Samuel Cochran
Perform email jobs in assert_emails.
Gannon McGibbon
Add Base.unregister_observer, Base.unregister_observers,
Base.unregister_interceptor, Base.unregister_interceptors,
Base.unregister_preview_interceptor and Base.unregister_preview_interceptors.
This makes it possible to dynamically add and remove email observers and
interceptors at runtime in the same way they're registered.
Claudio Ortolina, Kota Miyake
Rails 6 requires Ruby 2.5.0 or newer.
Jeremy Daer, Kasper Timm Hansen

Action Cable

Merge action-cable-testing to Rails.
Vladimir Dementyev
The JavaScript WebSocket client will no longer try to reconnect
when you call reject_unauthorized_connection on the connection.
Mick Staugaard
ActionCable.Connection#getState now references the configurable
ActionCable.adapters.WebSocket property rather than the WebSocket global
variable, matching the behavior of ActionCable.Connection#open.
Richard Macklin
The ActionCable javascript package has been converted from CoffeeScript
to ES2015, and we now publish the source code in the npm distribution.
This allows ActionCable users to depend on the javascript source code
rather than the compiled code, which can produce smaller javascript bundles.
This change includes some breaking changes to optional parts of the
ActionCable javascript API:
- Configuration of the WebSocket adapter and logger adapter have been moved
  from properties of ActionCable to properties of ActionCable.adapters.
  If you are currently configuring these adapters you will need to make
  these changes when upgrading:
```
-    ActionCable.WebSocket = MyWebSocket
+    ActionCable.adapters.WebSocket = MyWebSocket
```
```
-    ActionCable.logger = myLogger
+    ActionCable.adapters.logger = myLogger
```
- The ActionCable.startDebugging() and ActionCable.stopDebugging()
  methods have been removed and replaced with the property
  ActionCable.logger.enabled. If you are currently using these methods you
  will need to make these changes when upgrading:
```
-    ActionCable.startDebugging()
+    ActionCable.logger.enabled = true
```
```
-    ActionCable.stopDebugging()
+    ActionCable.logger.enabled = false
```
Richard Macklin

Add id option to redis adapter so now you can distinguish
ActionCable's redis connections among others. Also, you can set
custom id in options.

Before:

$ redis-cli client list
id=669 addr=127.0.0.1:46442 fd=8 name= age=18 ...

After:

$ redis-cli client list
id=673 addr=127.0.0.1:46516 fd=8 name=ActionCable-PID-19413 age=2 ...

Ilia Kasianenko

Rails 6 requires Ruby 2.5.0 or newer.
Jeremy Daer, Kasper Timm Hansen

Active Storage

Replace config.active_storage.queue with two options that indicate which
queues analysis and purge jobs should use, respectively:
- config.active_storage.queues.analysis
- config.active_storage.queues.purge
config.active_storage.queue is preferred over the new options when it's
set, but it is deprecated and will be removed in Rails 6.1.
George Claghorn
Permit generating variants of TIFF images.
Luciano Sousa
Use base36 (all lowercase) for all new Blob keys to prevent
collisions and undefined behavior with case-insensitive filesystems and
database indices.
Julik Tarkhanov
It doesn’t include an X-CSRF-Token header if a meta tag is not found on
the page. It previously included one with a value of undefined.
Cameron Bothner
Fix ArgumentError when uploading to amazon s3
Hiroki Sanpei
Add progressive JPG to default list of variable content types
Maurice Kühlborn
Add ActiveStorage.routes_prefix for configuring generated routes.
Chris Bisnett
ActiveStorage::Service::AzureStorageService only handles specifically
relevant types of Azure::Core::Http::HTTPError. It previously obscured
other types of HTTPError, which is the azure-storage gem’s catch-all
exception class.
Cameron Bothner
ActiveStorage::DiskController#show generates a 404 Not Found response when
the requested file is missing from the disk service. It previously raised
Errno::ENOENT.
Cameron Bothner
ActiveStorage::Blob#download and ActiveStorage::Blob#open raise
ActiveStorage::FileNotFoundError when the corresponding file is missing
from the storage service. Services translate service-specific missing object
exceptions (e.g. Google::Cloud::NotFoundError for the GCS service and
Errno::ENOENT for the disk service) into
ActiveStorage::FileNotFoundError.
Cameron Bothner
Added the ActiveStorage::SetCurrent concern for custom Active Storage
controllers that can't inherit from ActiveStorage::BaseController.
George Claghorn
Active Storage error classes like ActiveStorage::IntegrityError and
ActiveStorage::UnrepresentableError now inherit from ActiveStorage::Error
instead of StandardError. This permits rescuing ActiveStorage::Error to
handle all Active Storage errors.
Andrei Makarov, George Claghorn
Uploaded files assigned to a record are persisted to storage when the record
is saved instead of immediately.
In Rails 5.2, the following causes an uploaded file in params[:avatar] to
be stored:
```
@user.avatar = params[:avatar]
```
In Rails 6, the uploaded file is stored when @user is successfully saved.
George Claghorn
Add the ability to reflect on defined attachments using the existing
ActiveRecord reflection mechanism.
Kevin Deisz
Variant arguments of false or nil will no longer be passed to the
processor. For example, the following will not have the monochrome
variation applied:
```
  avatar.variant(monochrome: false)
```
Jacob Smith
Generated attachment getter and setter methods are created
within the model's GeneratedAssociationMethods module to
allow overriding and composition using super.
Josh Susser, Jamon Douglas
Add ActiveStorage::Blob#open, which downloads a blob to a tempfile on disk
and yields the tempfile. Deprecate ActiveStorage::Downloading.
David Robertson, George Claghorn
Pass in identify: false as an argument when providing a content_type for
ActiveStorage::Attached::{One,Many}#attach to bypass automatic content
type inference. For example:
```
  @message.image.attach(
    io: File.open('/path/to/file'),
    filename: 'file.pdf',
    content_type: 'application/pdf',
    identify: false
  )
```
Ryan Davidson
The Google Cloud Storage service properly supports streaming downloads.
It now requires version 1.11 or newer of the google-cloud-storage gem.
George Claghorn
Use the ImageProcessing gem
for Active Storage variants, and deprecate the MiniMagick backend.
This means that variants are now automatically oriented if the original
image was rotated. Also, in addition to the existing ImageMagick
operations, variants can now use :resize_to_fit, :resize_to_fill, and
other ImageProcessing macros. These are now recommended over raw :resize,
as they also sharpen the thumbnail after resizing.
The ImageProcessing gem also comes with a backend implemented on
libvips, an alternative to
ImageMagick which has significantly better performance than
ImageMagick in most cases, both in terms of speed and memory usage. In
Active Storage it's now possible to switch to the libvips backend by
changing Rails.application.config.active_storage.variant_processor to
:vips.
Janko Marohnić
Rails 6 requires Ruby 2.5.0 or newer.
Jeremy Daer, Kasper Timm Hansen

Action Mailbox

Added to Rails.
DHH

Action Text

Added to Rails.
DHH

Railties

Remove deprecated after_bundle helper inside plugins templates.
Rafael Mendonça França
Remove deprecated support to old config.ru that use the application class as argument of run.
Rafael Mendonça França
Remove deprecated environment argument from the rails commands.
Rafael Mendonça França
Remove deprecated capify!.
Rafael Mendonça França
Remove deprecated config.secret_token.
Rafael Mendonça França
Seed database with inline ActiveJob job adapter.
Gannon McGibbon
Add rails db:system:change command for changing databases.
```
bin/rails db:system:change --to=postgresql
   force  config/database.yml
    gsub  Gemfile
```
The change command copies a template config/database.yml with the target database adapter into your app, and replaces your database gem with the target database gem.
Gannon McGibbon
Add rails test:channels.
bogdanvlviv
Use original bundler environment variables during the process of generating a new rails project.
Marco Costa
Send Active Storage analysis and purge jobs to dedicated queues by default.
Analysis jobs now use the :active_storage_analysis queue, and purge jobs
now use the :active_storage_purge queue. This matches Action Mailbox,
which sends its jobs to dedicated queues by default.
George Claghorn
Add rails test:mailboxes.
George Claghorn
Introduce guard against DNS rebinding attacks
The ActionDispatch::HostAuthorization is a new middleware that prevent
against DNS rebinding and other Host header attacks. It is included in
the development environment by default with the following configuration:
```
Rails.application.config.hosts = [
  IPAddr.new("0.0.0.0/0"), # All IPv4 addresses.
  IPAddr.new("::/0"),      # All IPv6 addresses.
  "localhost"              # The localhost reserved domain.
]
```
In other environments Rails.application.config.hosts is empty and no
Host header checks will be done. If you want to guard against header
attacks on production, you have to manually whitelist the allowed hosts
with:
```
Rails.application.config.hosts << "product.com"
```
The host of a request is checked against the hosts entries with the case
operator (#===), which lets hosts support entries of type RegExp,
Proc and IPAddr to name a few. Here is an example with a regexp.
```
# Allow requests from subdomains like `www.product.com` and
# `beta1.product.com`.
Rails.application.config.hosts << /.*\.product\.com/
```
A special case is supported that allows you to whitelist all sub-domains:
```
# Allow requests from subdomains like `www.product.com` and
# `beta1.product.com`.
Rails.application.config.hosts << ".product.com"
```
Genadi Samokovarov
Remove redundant suffixes on generated helpers.
Gannon McGibbon
Remove redundant suffixes on generated integration tests.
Gannon McGibbon
Fix boolean interaction in scaffold system tests.
Gannon McGibbon
Remove redundant suffixes on generated system tests.
Gannon McGibbon
Add an abort_on_failure boolean option to the generator method that shell
out (generate, rake, rails_command) to abort the generator if the
command fails.
David Rodríguez
Remove app/assets and app/javascript from eager_load_paths and autoload_paths.
Gannon McGibbon
Use Ids instead of memory addresses when displaying references in scaffold views.
Fixes #29200.
Rasesh Patel
Adds support for multiple databases to rails db:migrate:status.
Subtasks are also added to get the status of individual databases (eg. rails db:migrate:status:animals).
Gannon McGibbon
Use Webpacker by default to manage app-level JavaScript through the new app/javascript directory.
Sprockets is now solely in charge, by default, of compiling CSS and other static assets.
Action Cable channel generators will create ES6 stubs rather than use CoffeeScript.
Active Storage, Action Cable, Turbolinks, and Rails-UJS are loaded by a new application.js pack.
Generators no longer generate JavaScript stubs.
DHH, Lachlan Sylvester
Add database (aliased as db) option to model generator to allow
setting the database. This is useful for applications that use
multiple databases and put migrations per database in their own directories.
```
bin/rails g model Room capacity:integer --database=kingston
      invoke  active_record
      create    db/kingston_migrate/20180830151055_create_rooms.rb
```
Because rails scaffolding uses the model generator, you can
also specify a database with the scaffold generator.
Gannon McGibbon
Raise an error when "recyclable cache keys" are being used by a cache store
that does not explicitly support it. Custom cache keys that do support this feature
can bypass this error by implementing the supports_cache_versioning? method on their
class and returning a truthy value.
Richard Schneeman
Support environment specific credentials overrides.
So any environment will look for config/credentials/#{Rails.env}.yml.enc and fall back
to config/credentials.yml.enc.
The encryption key can be in ENV["RAILS_MASTER_KEY"] or config/credentials/production.key.
Environment credentials overrides can be edited with rails credentials:edit --environment production.
If no override is setup for the passed environment, it will be created.
Additionally, the default lookup paths can be overwritten with these configs:
- config.credentials.content_path
- config.credentials.key_path
Wojciech Wnętrzak
Make ActiveSupport::Cache::NullStore the default cache store in the test environment.
Michael C. Nelson
Emit warning for unknown inflection rule when generating model.
Yoshiyuki Kinjo
Add database (aliased as db) option to migration generator.
If you're using multiple databases and have a folder for each database
for migrations (ex db/migrate and db/new_db_migrate) you can now pass the
--database option to the generator to make sure the the migration
is inserted into the correct folder.
```
rails g migration CreateHouses --database=kingston
  invoke  active_record
  create    db/kingston_migrate/20180830151055_create_houses.rb
```
Eileen M. Uchitelle
Deprecate rake routes in favor of rails routes.
Yuji Yaginuma
Deprecate rake initializers in favor of rails initializers.
Annie-Claude Côté
Deprecate rake dev:cache in favor of rails dev:cache.
Annie-Claude Côté
Deprecate rails notes subcommands in favor of passing an annotations argument to rails notes.
The following subcommands are replaced by passing --annotations or -a to rails notes:
- rails notes:custom ANNOTATION=custom is deprecated in favor of using rails notes -a custom.
- rails notes:optimize is deprecated in favor of using rails notes -a OPTIMIZE.
- rails notes:todo is deprecated in favor of usingrails notes -a TODO.
- rails notes:fixme is deprecated in favor of using rails notes -a FIXME.
Annie-Claude Côté
Deprecate SOURCE_ANNOTATION_DIRECTORIES environment variable used by rails notes
through Rails::SourceAnnotationExtractor::Annotation in favor of using config.annotations.register_directories.
Annie-Claude Côté
Deprecate rake notes in favor of rails notes.
Annie-Claude Côté
Don't generate unused files in app:update task.
Skip the assets' initializer when sprockets isn't loaded.
Skip config/spring.rb when spring isn't loaded.
Skip yarn's contents when yarn integration isn't used.
Tsukuru Tanimichi

Make the master.key file read-only for the owner upon generation on
POSIX-compliant systems.

Previously:

$ ls -l config/master.key
-rw-r--r--   1 owner  group      32 Jan 1 00:00 master.key

Now:

$ ls -l config/master.key
-rw-------   1 owner  group      32 Jan 1 00:00 master.key

Fixes #32604.

Jose Luis Duran

Deprecate support for using the HOST environment to specify the server IP.
The BINDING environment should be used instead.
Fixes #29516.
Yuji Yaginuma
Deprecate passing Rack server name as a regular argument to rails server.
Previously:
```
$ bin/rails server thin
```
There wasn't an explicit option for the Rack server to use, now we have the
--using option with the -u short switch.
Now:
```
$ bin/rails server -u thin
```
This change also improves the error message if a missing or mistyped rack
server is given.
Genadi Samokovarov

Add "rails routes --expanded" option to output routes in expanded mode like
"psql --expanded". Result looks like:

$ rails routes --expanded
--[ Route 1 ]------------------------------------------------------------
Prefix            | high_scores
Verb              | GET
URI               | /high_scores(.:format)
Controller#Action | high_scores#index
--[ Route 2 ]------------------------------------------------------------
Prefix            | new_high_score
Verb              | GET
URI               | /high_scores/new(.:format)
Controller#Action | high_scores#new

Benoit Tigeot

Rails 6 requires Ruby 2.5.0 or newer.
Jeremy Daer, Kasper Timm Hansen