CHANGELOG.md

• Allow Sqlite3Adapter to use sqlite3 gem version 2.x

  Mike Dalessio

• Strict loading using :n_plus_one_only does not eagerly load child associations.

  With this change, child associations are no longer eagerly loaded, to match intended behavior and to prevent non-deterministic order issues caused by calling methods like first or last. As first and last don't cause an N+1 by themselves, calling child associations will no longer raise. Fixes #49473.

  Before:

  person = Person.find(1)
  person.strict_loading!(mode: :n_plus_one_only)
  person.posts.first
  # SELECT * FROM posts WHERE person_id = 1; -- non-deterministic order
  person.posts.first.firm # raises ActiveRecord::StrictLoadingViolationError

  After:

  person = Person.find(1)
  person.strict_loading!(mode: :n_plus_one_only)
  person.posts.first # this is 1+1, not N+1
  # SELECT * FROM posts WHERE person_id = 1 ORDER BY id LIMIT 1;
  person.posts.first.firm # no longer raises

  Reid Lynch

• Using Model.query_constraints with a single non-primary-key column used to raise as expected, but with an incorrect error message. This has been fixed to raise with a more appropriate error message.

  Joshua Young

• Fix has_one association autosave setting the foreign key attribute when it is unchanged.

  This behaviour is also inconsistent with autosaving belongs_to and can have unintended side effects like raising an ActiveRecord::ReadOnlyAttributeError when the foreign key attribute is marked as read-only.

  Joshua Young

• Fix an issue where ActiveRecord::Encryption configurations are not ready before the loading of Active Record models, when an application is eager loaded. As a result, encrypted attributes could be misconfigured in some cases.

  Maxime Réty

• Properly synchronize Mysql2Adapter#active? and TrilogyAdapter#active?

  As well as disconnect! and verify!.

  This generally isn't a big problem as connections must not be shared between threads, but is required when running transactional tests or system tests and could lead to a SEGV.

  Jean Boussier

• Fix counter caches when the foreign key is composite.

  If the model holding the counter cache had a composite primary key, inserting a dependent record would fail with an ArgumentError Expected corresponding value for...

  fatkodima

• Fix loading of schema cache for multiple databases.

  Before this change, if you have multiple databases configured in your application, and had schema cache present, Rails would load the same cache to all databases.

  Rafael Mendonça França

• Fix eager loading of composite primary key associations.

  relation.eager_load(:other_model) could load the wrong records if other_model had a composite primary key.

  Nikita Vasilevsky

• Fix async queries returning a doubly wrapped result when hitting the query cache.

  fatkodima

• Fix single quote escapes on default generated MySQL columns

  MySQL 5.7.5+ supports generated columns, which can be used to create a column that is computed from an expression.

  Previously, the schema dump would output a string with double escapes for generated columns with single quotes in the default expression.

  This would result in issues when importing the schema on a fresh instance of a MySQL database.

  Now, the string will not be escaped and will be valid Ruby upon importing of the schema.

  Yash Kapadia

• Fix Migrations with versions older than 7.1 validating options given to t.references.

  Hartley McGuire

Rails 7.1.3.2 (February 21, 2024)

• No changes.

Rails 7.1.3.1 (February 21, 2024)

• No changes.

Rails 7.1.3 (January 16, 2024)

• Fix Migrations with versions older than 7.1 validating options given to add_reference.

  Hartley McGuire

• Ensure reload sets correct owner for each association.

  Dmytro Savochkin

• Fix view runtime for controllers with async queries.

  fatkodima

• Fix load_async to work with query cache.

  fatkodima

• Fix polymorphic belongs_to to correctly use parent's query_constraints.

  fatkodima

• Fix Preloader to not generate a query for already loaded association with query_constraints.

  fatkodima

• Fix multi-database polymorphic preloading with equivalent table names.

  When preloading polymorphic associations, if two models pointed to two tables with the same name but located in different databases, the preloader would only load one.

  Ari Summer

• Fix encrypted_attribute? to take into account context properties passed to encrypts.

  Maxime Réty

• Fix find_by to work correctly in presence of composite primary keys.

  fatkodima

• Fix async queries sometimes returning a raw result if they hit the query cache.

  ShipPart.async_count could return a raw integer rather than a Promise if it found the result in the query cache.

  fatkodima

• Fix Relation#transaction to not apply a default scope.

  The method was incorrectly setting a default scope around its block:

  Post.where(published: true).transaction do
    Post.count # SELECT COUNT(*) FROM posts WHERE published = FALSE;
  end

  Jean Boussier

• Fix calling async_pluck on a none relation.

  Model.none.async_pluck(:id) was returning a naked value instead of a promise.

  Jean Boussier

• Fix calling load_async on a none relation.

  Model.none.load_async was returning a broken result.

  Lucas Mazza

• TrilogyAdapter: ignore host if socket parameter is set.

  This allows to configure a connection on a UNIX socket via DATABASE_URL:

  DATABASE_URL=trilogy://does-not-matter/my_db_production?socket=/var/run/mysql.sock
  

  Jean Boussier

• Fix has_secure_token calls the setter method on initialize.

  Abeid Ahmed

• Allow using object_id as a database column name. It was available before rails 7.1 and may be used as a part of polymorphic relationship to object where object can be any other database record.

  Mikhail Doronin

• Fix rails db:create:all to not touch databases before they are created.

  fatkodima

Rails 7.1.2 (November 10, 2023)

• Fix renaming primary key index when renaming a table with a UUID primary key in PostgreSQL.

  fatkodima

• Fix where(field: values) queries when field is a serialized attribute (for example, when field uses ActiveRecord::Base.serialize or is a JSON column).

  João Alves

• Prevent marking broken connections as verified.

  Daniel Colson

• Don't mark Float::INFINITY as changed when reassigning it

  When saving a record with a float infinite value, it shouldn't mark as changed

  Maicol Bentancor

• ActiveRecord::Base.table_name now returns nil instead of raising "undefined method abstract_class? for Object:Class".

  a5-stable

• Fix upserting for custom :on_duplicate and :unique_by consisting of all inserts keys.

  fatkodima

• Fixed an issue where saving a record could innappropriately dup its attributes.

  Jonathan Hefner

• Dump schema only for a specific db for rollback/up/down tasks for multiple dbs.

  fatkodima

• Fix NoMethodError when casting a PostgreSQL money value that uses a comma as its radix point and has no leading currency symbol. For example, when casting "3,50".

  Andreas Reischuck and Jonathan Hefner

• Re-enable support for using enum with non-column-backed attributes. Non-column-backed attributes must be previously declared with an explicit type. For example:

  class Post < ActiveRecord::Base
    attribute :topic, :string
    enum topic: %i[science tech engineering math]
  end

  Jonathan Hefner

• Raise on foreign_key: being passed as an array in associations

  Nikita Vasilevsky

• Return back maximum allowed PostgreSQL table name to 63 characters.

  fatkodima

• Fix detecting IDENTITY columns for PostgreSQL < 10.

  fatkodima

Rails 7.1.1 (October 11, 2023)

• Fix auto populating IDENTITY columns for PostgreSQL.

  fatkodima

• Fix "ArgumentError: wrong number of arguments (given 3, expected 2)" when down migrating rename_table in older migrations.

  fatkodima

• Do not require the Action Text, Active Storage and Action Mailbox tables to be present when running when running test on CI.

  Rafael Mendonça França

Rails 7.1.0 (October 05, 2023)

• No changes.

Rails 7.1.0.rc2 (October 01, 2023)

• Remove -shm and -wal SQLite files when rails db:drop is run.

  Niklas Häusele

• Revert the change to raise an ArgumentError when #accepts_nested_attributes_for is declared more than once for an association in the same class.

  The reverted behavior broke the case where the #accepts_nested_attributes_for was defined in a concern and where overridden in the class that included the concern.

  Rafael Mendonça França

Rails 7.1.0.rc1 (September 27, 2023)

• Better naming for unique constraints support.

  Naming unique keys leads to misunderstanding it's a short-hand of unique indexes. Just naming it unique constraints is not misleading.

  In Rails 7.1.0.beta1 or before:

  add_unique_key :sections, [:position], deferrable: :deferred, name: "unique_section_position"
  remove_unique_key :sections, name: "unique_section_position"

  Now:

  add_unique_constraint :sections, [:position], deferrable: :deferred, name: "unique_section_position"
  remove_unique_constraint :sections, name: "unique_section_position"

  Ryuta Kamizono

• Fix duplicate quoting for check constraint expressions in schema dump when using MySQL

  A check constraint with an expression, that already contains quotes, lead to an invalid schema dump with the mysql2 adapter.

  Fixes #42424.

  Felix Tscheulin

• Performance tune the SQLite3 adapter connection configuration

  For Rails applications, the Write-Ahead-Log in normal syncing mode with a capped journal size, a healthy shared memory buffer and a shared cache will perform, on average, 2× better.

  Stephen Margheim

• Allow SQLite3 busy_handler to be configured with simple max number of retries

  Retrying busy connections without delay is a preferred practice for performance-sensitive applications. Add support for a database.yml retries integer, which is used in a simple busy_handler function to retry busy connections without exponential backoff up to the max number of retries.

  Stephen Margheim

• The SQLite3 adapter now supports supports_insert_returning?

  Implementing the full supports_insert_returning? contract means the SQLite3 adapter supports auto-populated columns (#48241) as well as custom primary keys.

  Stephen Margheim

• Ensure the SQLite3 adapter handles default functions with the || concatenation operator

  Previously, this default function would produce the static string "'Ruby ' || 'on ' || 'Rails'". Now, the adapter will appropriately receive and use "Ruby on Rails".

  change_column_default "test_models", "ruby_on_rails", -> { "('Ruby ' || 'on ' || 'Rails')" }

  Stephen Margheim

• Dump PostgreSQL schemas as part of the schema dump.

  Lachlan Sylvester

Rails 7.1.0.beta1 (September 13, 2023)

• Encryption now supports support_unencrypted_data being set per-attribute.

  You can now opt out of support_unencrypted_data on a specific encrypted attribute. This only has an effect if ActiveRecord::Encryption.config.support_unencrypted_data == true.

  class User < ActiveRecord::Base
    encrypts :name, deterministic: true, support_unencrypted_data: false
    encrypts :email, deterministic: true
  end

  Alex Ghiculescu

• Add instrumentation for Active Record transactions

  Allows subscribing to transaction events for tracking/instrumentation. The event payload contains the connection and the outcome (commit, rollback, restart, incomplete), as well as timing details.

  ActiveSupport::Notifications.subscribe("transaction.active_record") do |event|
    puts "Transaction event occurred!"
    connection = event.payload[:connection]
    puts "Connection: #{connection.inspect}"
  end

  Daniel Colson, Ian Candy

• Support composite foreign keys via migration helpers.

  # Assuming "carts" table has "(shop_id, user_id)" as a primary key.
  
  add_foreign_key(:orders, :carts, primary_key: [:shop_id, :user_id])
  
  remove_foreign_key(:orders, :carts, primary_key: [:shop_id, :user_id])
  foreign_key_exists?(:orders, :carts, primary_key: [:shop_id, :user_id])

  fatkodima

• Adds support for if_not_exists when adding a check constraint.

  add_check_constraint :posts, "post_type IN ('blog', 'comment', 'share')", if_not_exists: true

  Cody Cutrer

• Raise an ArgumentError when #accepts_nested_attributes_for is declared more than once for an association in the same class. Previously, the last declaration would silently override the previous one. Overriding in a subclass is still allowed.

  Joshua Young

• Deprecate rewhere argument on #merge.

  The rewhere argument on #mergeis deprecated without replacement and will be removed in Rails 7.2.

  Adam Hess

• Deprecate aliasing non-attributes with alias_attribute.

  Ian Candy

• Fix unscope is not working in specific case

  Before:

  Post.where(id: 1...3).unscope(where: :id).to_sql # "SELECT `posts`.* FROM `posts` WHERE `posts`.`id` >= 1 AND `posts`.`id` < 3"

  After:

  Post.where(id: 1...3).unscope(where: :id).to_sql # "SELECT `posts`.* FROM `posts`"

  Fixes #48094.

  Kazuya Hatanaka

• Change has_secure_token default to on: :initialize

  Change the new default value from on: :create to on: :initialize

  Can be controlled by the config.active_record.generate_secure_token_on configuration:

  config.active_record.generate_secure_token_on = :create

  Sean Doyle

• Fix change_column not setting precision: 6 on datetime columns when using 7.0+ Migrations and SQLite.

  Hartley McGuire

• Support composite identifiers in to_key

  to_key avoids wrapping #id value into an Array if #id already an array

  Nikita Vasilevsky

• Add validation option for enum

  class Contract < ApplicationRecord
    enum :status, %w[in_progress completed], validate: true
  end
  Contract.new(status: "unknown").valid? # => false
  Contract.new(status: nil).valid? # => false
  Contract.new(status: "completed").valid? # => true
  
  class Contract < ApplicationRecord
    enum :status, %w[in_progress completed], validate: { allow_nil: true }
  end
  Contract.new(status: "unknown").valid? # => false
  Contract.new(status: nil).valid? # => true
  Contract.new(status: "completed").valid? # => true

  Edem Topuzov, Ryuta Kamizono

• Allow batching methods to use already loaded relation if available

  Calling batch methods on already loaded relations will use the records previously loaded instead of retrieving them from the database again.

  Adam Hess

• Deprecate read_attribute(:id) returning the primary key if the primary key is not :id.

  Starting in Rails 7.2, read_attribute(:id) will return the value of the id column, regardless of the model's primary key. To retrieve the value of the primary key, use #id instead. read_attribute(:id) for composite primary key models will now return the value of the id column.

  Adrianna Chang

• Fix change_table setting datetime precision for 6.1 Migrations

  Hartley McGuire

• Fix change_column setting datetime precision for 6.1 Migrations

  Hartley McGuire

• Add ActiveRecord::Base#id_value alias to access the raw value of a record's id column.

  This alias is only provided for models that declare an :id column.

  Adrianna Chang

• Fix previous change tracking for ActiveRecord::Store when using a column with JSON structured database type

  Before, the methods to access the changes made during the last save #saved_change_to_key?, #saved_change_to_key, and #key_before_last_save did not work if the store was defined as a store_accessor on a column with a JSON structured database type

  Robert DiMartino

• Fully support NULLS [NOT] DISTINCT for PostgreSQL 15+ indexes.

  Previous work was done to allow the index to be created in a migration, but it was not supported in schema.rb. Additionally, the matching for NULLS [NOT] DISTINCT was not in the correct order, which could have resulted in inconsistent schema detection.

  Gregory Jones

• Allow escaping of literal colon characters in sanitize_sql_* methods when named bind variables are used

  Justin Bull

• Fix #previously_new_record? to return true for destroyed records.

  Before, if a record was created and then destroyed, #previously_new_record? would return true. Now, any UPDATE or DELETE to a record is considered a change, and will result in #previously_new_record? returning false.

  Adrianna Chang

• Specify callback in has_secure_token

  class User < ApplicationRecord
    has_secure_token on: :initialize
  end
  
  User.new.token # => "abc123...."

  Sean Doyle

• Fix incrementation of in memory counter caches when associations overlap

  When two associations had a similarly named counter cache column, Active Record could sometime increment the wrong one.

  Jacopo Beschi, Jean Boussier

• Don't show secrets for Active Record's Cipher::Aes256Gcm#inspect.

  Before:

  ActiveRecord::Encryption::Cipher::Aes256Gcm.new(secret).inspect
  "#<ActiveRecord::Encryption::Cipher::Aes256Gcm:0x0000000104888038 ... @secret=\"\\xAF\\bFh]LV}q\\nl\\xB2U\\xB3 ... >"

  After:

  ActiveRecord::Encryption::Cipher::Aes256Gcm(secret).inspect
  "#<ActiveRecord::Encryption::Cipher::Aes256Gcm:0x0000000104888038>"

  Petrik de Heus

• Bring back the historical behavior of committing transaction on non-local return.

  Model.transaction do
    model.save
    return
    other_model.save # not executed
  end

  Historically only raised errors would trigger a rollback, but in Ruby 2.3, the timeout library started using throw to interrupt execution which had the adverse effect of committing open transactions.

  To solve this, in Active Record 6.1 the behavior was changed to instead rollback the transaction as it was safer than to potentially commit an incomplete transaction.

  Using return, break or throw inside a transaction block was essentially deprecated from Rails 6.1 onwards.

  However with the release of timeout 0.4.0, Timeout.timeout now raises an error again, and Active Record is able to return to its original, less surprising, behavior.

  This historical behavior can now be opt-ed in via:

  Rails.application.config.active_record.commit_transaction_on_non_local_return = true
  

  And is the default for new applications created in Rails 7.1.

  Jean Boussier

• Deprecate name argument on #remove_connection.

  The name argument is deprecated on #remove_connection without replacement. #remove_connection should be called directly on the class that established the connection.

  Eileen M. Uchitelle

• Fix has_one through singular building with inverse.

  Allows building of records from an association with a has_one through a singular association with inverse. For belongs_to through associations, linking the foreign key to the primary key model isn't needed. For has_one, we cannot build records due to the association not being mutable.

  Gannon McGibbon

• Disable database prepared statements when query logs are enabled

  Prepared Statements and Query Logs are incompatible features due to query logs making every query unique.

  zzak, Jean Boussier

• Support decrypting data encrypted non-deterministically with a SHA1 hash digest.

  This adds a new Active Record encryption option to support decrypting data encrypted non-deterministically with a SHA1 hash digest:

  Rails.application.config.active_record.encryption.support_sha1_for_non_deterministic_encryption = true
  

  The new option addresses a problem when upgrading from 7.0 to 7.1. Due to a bug in how Active Record Encryption was getting initialized, the key provider used for non-deterministic encryption were using SHA-1 as its digest class, instead of the one configured globally by Rails via Rails.application.config.active_support.key_generator_hash_digest_class.

  Cadu Ribeiro and Jorge Manrubia

• Added PostgreSQL migration commands for enum rename, add value, and rename value.

  rename_enum and rename_enum_value are reversible. Due to Postgres limitation, add_enum_value is not reversible since you cannot delete enum values. As an alternative you should drop and recreate the enum entirely.

  rename_enum :article_status, to: :article_state

  add_enum_value :article_state, "archived" # will be at the end of existing values
  add_enum_value :article_state, "in review", before: "published"
  add_enum_value :article_state, "approved", after: "in review"

  rename_enum_value :article_state, from: "archived", to: "deleted"

  Ray Faddis

• Allow composite primary key to be derived from schema

  Booting an application with a schema that contains composite primary keys will not issue warning and won't nilify the ActiveRecord::Base#primary_key value anymore.

  Given a travel_routes table definition and a TravelRoute model like:

  create_table :travel_routes, primary_key: [:origin, :destination], force: true do |t|
    t.string :origin
    t.string :destination
  end
  
  class TravelRoute < ActiveRecord::Base; end

  The TravelRoute.primary_key value will be automatically derived to ["origin", "destination"]

  Nikita Vasilevsky

• Include the connection_pool with exceptions raised from an adapter.

  The connection_pool provides added context such as the connection used that led to the exception as well as which role and shard.

  Luan Vieira

• Support multiple column ordering for find_each, find_in_batches and in_batches.

  When find_each/find_in_batches/in_batches are performed on a table with composite primary keys, ascending or descending order can be selected for each key.

  Person.find_each(order: [:desc, :asc]) do |person|
    person.party_all_night!
  end

  Takuya Kurimoto

• Fix where on association with has_one/has_many polymorphic relations.

  Before:

  Treasure.where(price_estimates: PriceEstimate.all)
  #=> SELECT (...) WHERE "treasures"."id" IN (SELECT "price_estimates"."estimate_of_id" FROM "price_estimates")

  Later:

  Treasure.where(price_estimates: PriceEstimate.all)
  #=> SELECT (...) WHERE "treasures"."id" IN (SELECT "price_estimates"."estimate_of_id" FROM "price_estimates" WHERE "price_estimates"."estimate_of_type" = 'Treasure')

  Lázaro Nixon

• Assign auto populated columns on Active Record record creation.

  Changes record creation logic to allow for the auto_increment column to be assigned immediately after creation regardless of it's relation to the model's primary key.

  The PostgreSQL adapter benefits the most from the change allowing for any number of auto-populated columns to be assigned on the object immediately after row insertion utilizing the RETURNING statement.

  Nikita Vasilevsky

• Use the first key in the shards hash from connected_to for the default_shard.

  Some applications may not want to use :default as a shard name in their connection model. Unfortunately Active Record expects there to be a :default shard because it must assume a shard to get the right connection from the pool manager. Rather than force applications to manually set this, connects_to can infer the default shard name from the hash of shards and will now assume that the first shard is your default.

  For example if your model looked like this:

  class ShardRecord < ApplicationRecord
    self.abstract_class = true
  
    connects_to shards: {
      shard_one: { writing: :shard_one },
      shard_two: { writing: :shard_two }
    }

  Then the default_shard for this class would be set to shard_one.

  Fixes: #45390

  Eileen M. Uchitelle

• Fix mutation detection for serialized attributes backed by binary columns.

  Jean Boussier

• Add ActiveRecord.disconnect_all! method to immediately close all connections from all pools.

  Jean Boussier

• Discard connections which may have been left in a transaction.

  There are cases where, due to an error, within_new_transaction may unexpectedly leave a connection in an open transaction. In these cases the connection may be reused, and the following may occur:

  • Writes appear to fail when they actually succeed.
  • Writes appear to succeed when they actually fail.
  • Reads return stale or uncommitted data.

  Previously, the following case was detected:

  • An error is encountered during the transaction, then another error is encountered while attempting to roll it back.

  Now, the following additional cases are detected:

  • An error is encountered just after successfully beginning a transaction.
  • An error is encountered while committing a transaction, then another error is encountered while attempting to roll it back.
  • An error is encountered while rolling back a transaction.

  Nick Dower

• Active Record query cache now evicts least recently used entries

  By default it only keeps the 100 most recently used queries.

  The cache size can be configured via database.yml

  development:
    adapter: mysql2
    query_cache: 200

  It can also be entirely disabled:

  development:
    adapter: mysql2
    query_cache: false

  Jean Boussier

• Deprecate check_pending! in favor of check_all_pending!.

  check_pending! will only check for pending migrations on the current database connection or the one passed in. This has been deprecated in favor of check_all_pending! which will find all pending migrations for the database configurations in a given environment.

  Eileen M. Uchitelle

• Make increment_counter/decrement_counter accept an amount argument

  Post.increment_counter(:comments_count, 5, by: 3)

  fatkodima

• Add support for Array#intersect? to ActiveRecord::Relation.

  Array#intersect? is only available on Ruby 3.1 or later.

  This allows the Rubocop Style/ArrayIntersect cop to work with ActiveRecord::Relation objects.

  John Harry Kelly

• The deferrable foreign key can be passed to t.references.

  Hiroyuki Ishii

• Deprecate deferrable: true option of add_foreign_key.

  deferrable: true is deprecated in favor of deferrable: :immediate, and will be removed in Rails 7.2.

  Because deferrable: true and deferrable: :deferred are hard to understand. Both true and :deferred are truthy values. This behavior is the same as the deferrable option of the add_unique_key method, added in #46192.

  Hiroyuki Ishii

• AbstractAdapter#execute and #exec_query now clear the query cache

  If you need to perform a read only SQL query without clearing the query cache, use AbstractAdapter#select_all.

  Jean Boussier

• Make .joins / .left_outer_joins work with CTEs.

  For example:

  Post
   .with(commented_posts: Comment.select(:post_id).distinct)
   .joins(:commented_posts)
  #=> WITH (...) SELECT ... INNER JOIN commented_posts on posts.id = commented_posts.post_id

  Vladimir Dementyev

• Add a load hook for ActiveRecord::ConnectionAdapters::Mysql2Adapter (named active_record_mysql2adapter) to allow for overriding aspects of the ActiveRecord::ConnectionAdapters::Mysql2Adapter class. This makes Mysql2Adapter consistent with PostgreSQLAdapter and SQLite3Adapter that already have load hooks.

  fatkodima

• Introduce adapter for Trilogy database client

  Trilogy is a MySQL-compatible database client. Rails applications can use Trilogy by configuring their config/database.yml:

  development:
  adapter: trilogy
  database: blog_development
  pool: 5

  Or by using the DATABASE_URL environment variable:

  ENV['DATABASE_URL'] # => "trilogy://localhost/blog_development?pool=5"

  Adrianna Chang

• after_commit callbacks defined on models now execute in the correct order.

  class User < ActiveRecord::Base
    after_commit { puts("this gets called first") }
    after_commit { puts("this gets called second") }
  end

  Previously, the callbacks executed in the reverse order. To opt in to the new behaviour:

  config.active_record.run_after_transaction_callbacks_in_order_defined = true

  This is the default for new apps.

  Alex Ghiculescu

• Infer foreign_key when inverse_of is present on has_one and has_many associations.

  has_many :citations, foreign_key: "book1_id", inverse_of: :book

  can be simplified to

  has_many :citations, inverse_of: :book

  and the foreign_key will be read from the corresponding belongs_to association.

  Daniel Whitney

• Limit max length of auto generated index names

  Auto generated index names are now limited to 62 bytes, which fits within the default index name length limits for MySQL, Postgres and SQLite.

  Any index name over the limit will fallback to the new short format.

  Before (too long):

  index_testings_on_foo_and_bar_and_first_name_and_last_name_and_administrator
  

  After (short format):

  idx_on_foo_bar_first_name_last_name_administrator_5939248142
  

  The short format includes a hash to ensure the name is unique database-wide.

  Mike Coutermarsh

• Introduce a more stable and optimized Marshal serializer for Active Record models.

  Can be enabled with config.active_record.marshalling_format_version = 7.1.

  Jean Boussier

• Allow specifying where clauses with column-tuple syntax.

  Querying through #where now accepts a new tuple-syntax which accepts, as a key, an array of columns and, as a value, an array of corresponding tuples. The key specifies a list of columns, while the value is an array of ordered-tuples that conform to the column list.

  For instance:

  # Cpk::Book => Cpk::Book(author_id: integer, number: integer, title: string, revision: integer)
  # Cpk::Book.primary_key => ["author_id", "number"]
  
  book = Cpk::Book.create!(author_id: 1, number: 1)
  Cpk::Book.where(Cpk::Book.primary_key => [[1, 2]]) # => [book]
  
  # Topic => Topic(id: integer, title: string, author_name: string...)
  
  Topic.where([:title, :author_name] => [["The Alchemist", "Paulo Coelho"], ["Harry Potter", "J.K Rowling"]])

  Paarth Madan

• Allow warning codes to be ignore when reporting SQL warnings.

  Active Record config that can ignore warning codes

  # Configure allowlist of warnings that should always be ignored
  config.active_record.db_warnings_ignore = [
    "1062", # MySQL Error 1062: Duplicate entry
  ]

  This is supported for the MySQL and PostgreSQL adapters.

  Nick Borromeo

• Introduce :active_record_fixtures lazy load hook.

  Hooks defined with this name will be run whenever TestFixtures is included in a class.

  ActiveSupport.on_load(:active_record_fixtures) do
    self.fixture_paths << "test/fixtures"
  end
  
  klass = Class.new
  klass.include(ActiveRecord::TestFixtures)
  
  klass.fixture_paths # => ["test/fixtures"]

  Andrew Novoselac

• Introduce TestFixtures#fixture_paths.

  Multiple fixture paths can now be specified using the #fixture_paths accessor. Apps will continue to have test/fixtures as their one fixture path by default, but additional fixture paths can be specified.

  ActiveSupport::TestCase.fixture_paths << "component1/test/fixtures"
  ActiveSupport::TestCase.fixture_paths << "component2/test/fixtures"

  TestFixtures#fixture_path is now deprecated.

  Andrew Novoselac

• Adds support for deferrable exclude constraints in PostgreSQL.

  By default, exclude constraints in PostgreSQL are checked after each statement. This works for most use cases, but becomes a major limitation when replacing records with overlapping ranges by using multiple statements.

  exclusion_constraint :users, "daterange(valid_from, valid_to) WITH &&", deferrable: :immediate

  Passing deferrable: :immediate checks constraint after each statement, but allows manually deferring the check using SET CONSTRAINTS ALL DEFERRED within a transaction. This will cause the excludes to be checked after the transaction.

  It's also possible to change the default behavior from an immediate check (after the statement), to a deferred check (after the transaction):

  exclusion_constraint :users, "daterange(valid_from, valid_to) WITH &&", deferrable: :deferred

  Hiroyuki Ishii

• Respect foreign_type option to delegated_type for {role}_class method.

  Usage of delegated_type with non-conventional {role}_type column names can now be specified with foreign_type option. This option is the same as foreign_type as forwarded to the underlying belongs_to association that delegated_type wraps.

  Jason Karns

• Add support for unique constraints (PostgreSQL-only).

  add_unique_key :sections, [:position], deferrable: :deferred, name: "unique_section_position"
  remove_unique_key :sections, name: "unique_section_position"

  See PostgreSQL's Unique Constraints documentation for more on unique constraints.

  By default, unique constraints in PostgreSQL are checked after each statement. This works for most use cases, but becomes a major limitation when replacing records with unique column by using multiple statements.

  An example of swapping unique columns between records.

  # position is unique column
  old_item = Item.create!(position: 1)
  new_item = Item.create!(position: 2)
  
  Item.transaction do
    old_item.update!(position: 2)
    new_item.update!(position: 1)
  end

  Using the default behavior, the transaction would fail when executing the first UPDATE statement.

  By passing the :deferrable option to the add_unique_key statement in migrations, it's possible to defer this check.

  add_unique_key :items, [:position], deferrable: :immediate

  Passing deferrable: :immediate does not change the behaviour of the previous example, but allows manually deferring the check using SET CONSTRAINTS ALL DEFERRED within a transaction. This will cause the unique constraints to be checked after the transaction.

  It's also possible to adjust the default behavior from an immediate check (after the statement), to a deferred check (after the transaction):

  add_unique_key :items, [:position], deferrable: :deferred

  If you want to change an existing unique index to deferrable, you can use :using_index to create deferrable unique constraints.

  add_unique_key :items, deferrable: :deferred, using_index: "index_items_on_position"

  Hiroyuki Ishii

• Remove deprecated Tasks::DatabaseTasks.schema_file_type.

  Rafael Mendonça França

• Remove deprecated config.active_record.partial_writes.

  Rafael Mendonça França

• Remove deprecated ActiveRecord::Base config accessors.

  Rafael Mendonça França

• Remove the :include_replicas argument from configs_for. Use :include_hidden argument instead.

  Eileen M. Uchitelle

• Allow applications to lookup a config via a custom hash key.

  If you have registered a custom config or want to find configs where the hash matches a specific key, now you can pass config_key to configs_for. For example if you have a db_config with the key vitess you can look up a database configuration hash by matching that key.

  ActiveRecord::Base.configurations.configs_for(env_name: "development", name: "primary", config_key: :vitess)
  ActiveRecord::Base.configurations.configs_for(env_name: "development", config_key: :vitess)

  Eileen M. Uchitelle

• Allow applications to register a custom database configuration handler.

  Adds a mechanism for registering a custom handler for cases where you want database configurations to respond to custom methods. This is useful for non-Rails database adapters or tools like Vitess that you may want to configure differently from a standard HashConfig or UrlConfig.

  Given the following database YAML we want the animals db to create a CustomConfig object instead while the primary database will be a UrlConfig:

  development:
    primary:
      url: postgres://localhost/primary
    animals:
      url: postgres://localhost/animals
      custom_config:
        sharded: 1

  To register a custom handler first make a class that has your custom methods:

  class CustomConfig < ActiveRecord::DatabaseConfigurations::UrlConfig
    def sharded?
      custom_config.fetch("sharded", false)
    end
  
    private
      def custom_config
        configuration_hash.fetch(:custom_config)
      end
  end

  Then register the config in an initializer:

  ActiveRecord::DatabaseConfigurations.register_db_config_handler do |env_name, name, url, config|
    next unless config.key?(:custom_config)
    CustomConfig.new(env_name, name, url, config)
  end

  When the application is booted, configuration hashes with the :custom_config key will be CustomConfig objects and respond to sharded?. Applications must handle the condition in which Active Record should use their custom handler.

  Eileen M. Uchitelle and John Crepezzi

• ActiveRecord::Base.serialize no longer uses YAML by default.

  YAML isn't particularly performant and can lead to security issues if not used carefully.

  Unfortunately there isn't really any good serializers in Ruby's stdlib to replace it.

  The obvious choice would be JSON, which is a fine format for this use case, however the JSON serializer in Ruby's stdlib isn't strict enough, as it fallback to casting unknown types to strings, which could lead to corrupted data.

  Some third party JSON libraries like Oj have a suitable strict mode.

  So it's preferable that users choose a serializer based on their own constraints.

  The original default can be restored by setting config.active_record.default_column_serializer = YAML.

  Jean Boussier

• ActiveRecord::Base.serialize signature changed.

  Rather than a single positional argument that accepts two possible types of values, serialize now accepts two distinct keyword arguments.

  Before:

  serialize :content, JSON
  serialize :backtrace, Array

  After:

  serialize :content, coder: JSON
  serialize :backtrace, type: Array

  Jean Boussier

• YAML columns use YAML.safe_dump if available.

  As of psych 5.1.0, YAML.safe_dump can now apply the same permitted types restrictions than YAML.safe_load.

  It's preferable to ensure the payload only use allowed types when we first try to serialize it, otherwise you may end up with invalid records in the database.

  Jean Boussier

• ActiveRecord::QueryLogs better handle broken encoding.

  It's not uncommon when building queries with BLOB fields to contain binary data. Unless the call carefully encode the string in ASCII-8BIT it generally end up being encoded in UTF-8, and QueryLogs would end up failing on it.

  ActiveRecord::QueryLogs no longer depend on the query to be properly encoded.

  Jean Boussier

• Fix a bug where ActiveRecord::Generators::ModelGenerator would not respect create_table_migration template overrides.

  rails g model create_books title:string content:text
  

  will now read from the create_table_migration.rb.tt template in the following locations in order:

  lib/templates/active_record/model/create_table_migration.rb
  lib/templates/active_record/migration/create_table_migration.rb
  

  Spencer Neste

• ActiveRecord::Relation#explain now accepts options.

  For databases and adapters which support them (currently PostgreSQL and MySQL), options can be passed to explain to provide more detailed query plan analysis:

  Customer.where(id: 1).joins(:orders).explain(:analyze, :verbose)

  Reid Lynch

• Multiple Arel::Nodes::SqlLiteral nodes can now be added together to form Arel::Nodes::Fragments nodes. This allows joining several pieces of SQL.

  Matthew Draper, Ole Friis

• ActiveRecord::Base#signed_id raises if called on a new record.

  Previously it would return an ID that was not usable, since it was based on id = nil.

  Alex Ghiculescu

• Allow SQL warnings to be reported.

  Active Record configs can be set to enable SQL warning reporting.

  # Configure action to take when SQL query produces warning
  config.active_record.db_warnings_action = :raise
  
  # Configure allowlist of warnings that should always be ignored
  config.active_record.db_warnings_ignore = [
    /Invalid utf8mb4 character string/,
    "An exact warning message",
  ]

  This is supported for the MySQL and PostgreSQL adapters.

  Adrianna Chang, Paarth Madan

• Add #regroup query method as a short-hand for .unscope(:group).group(fields)

  Example:

  Post.group(:title).regroup(:author)
  # SELECT `posts`.`*` FROM `posts` GROUP BY `posts`.`author`

  Danielius Visockas

• PostgreSQL adapter method enable_extension now allows parameter to be [schema_name.]<extension_name> if the extension must be installed on another schema.

  Example: enable_extension('heroku_ext.hstore')

  Leonardo Luarte

• Add :include option to add_index.

  Add support for including non-key columns in indexes for PostgreSQL with the INCLUDE parameter.

  add_index(:users, :email, include: [:id, :created_at])

  will result in:

  CREATE INDEX index_users_on_email USING btree (email) INCLUDE (id, created_at)

  Steve Abrams

• ActiveRecord::Relation’s #any?, #none?, and #one? methods take an optional pattern argument, more closely matching their Enumerable equivalents.

  George Claghorn

• Add ActiveRecord::Base.normalizes for declaring attribute normalizations.

  An attribute normalization is applied when the attribute is assigned or updated, and the normalized value will be persisted to the database. The normalization is also applied to the corresponding keyword argument of query methods, allowing records to be queried using unnormalized values.

  For example:

  class User < ActiveRecord::Base
    normalizes :email, with: -> email { email.strip.downcase }
    normalizes :phone, with: -> phone { phone.delete("^0-9").delete_prefix("1") }
  end
  
  user = User.create(email: " CRUISE-CONTROL@EXAMPLE.COM\n")
  user.email                  # => "cruise-control@example.com"
  
  user = User.find_by(email: "\tCRUISE-CONTROL@EXAMPLE.COM ")
  user.email                  # => "cruise-control@example.com"
  user.email_before_type_cast # => "cruise-control@example.com"
  
  User.where(email: "\tCRUISE-CONTROL@EXAMPLE.COM ").count         # => 1
  User.where(["email = ?", "\tCRUISE-CONTROL@EXAMPLE.COM "]).count # => 0
  
  User.exists?(email: "\tCRUISE-CONTROL@EXAMPLE.COM ")         # => true
  User.exists?(["email = ?", "\tCRUISE-CONTROL@EXAMPLE.COM "]) # => false
  
  User.normalize_value_for(:phone, "+1 (555) 867-5309") # => "5558675309"

  Jonathan Hefner

• Hide changes to before_committed! callback behaviour behind flag.

  In #46525, behavior around before_committed! callbacks was changed so that callbacks would run on every enrolled record in a transaction, not just the first copy of a record. This change in behavior is now controlled by a configuration option, config.active_record.before_committed_on_all_records. It will be enabled by default on Rails 7.1.

  Adrianna Chang

• The namespaced_controller Query Log tag now matches the controller format

  For example, a request processed by NameSpaced::UsersController will now log as:

  :controller # "users"
  :namespaced_controller # "name_spaced/users"
  

  Alex Ghiculescu

• Return only unique ids from ActiveRecord::Calculations#ids

  Updated ActiveRecord::Calculations#ids to only return the unique ids of the base model when using eager_load, preload and includes.

  Post.find_by(id: 1).comments.count
  # => 5
  Post.includes(:comments).where(id: 1).pluck(:id)
  # => [1, 1, 1, 1, 1]
  Post.includes(:comments).where(id: 1).ids
  # => [1]

  Joshua Young

• Stop using LOWER() for case-insensitive queries on citext columns

  Previously, LOWER() was added for e.g. uniqueness validations with case_sensitive: false. It wasn't mentioned in the documentation that the index without LOWER() wouldn't be used in this case.

  Phil Pirozhkov

• Extract #sync_timezone_changes method in AbstractMysqlAdapter to enable subclasses to sync database timezone changes without overriding #raw_execute.

  Adrianna Chang, Paarth Madan

• Do not write additional new lines when dumping sql migration versions

  This change updates the insert_versions_sql function so that the database insert string containing the current database migration versions does not end with two additional new lines.

  Misha Schwartz

• Fix composed_of value freezing and duplication.

  Previously composite values exhibited two confusing behaviors:

  • When reading a compositve value it'd NOT be frozen, allowing it to get out of sync with its underlying database columns.
  • When writing a compositve value the argument would be frozen, potentially confusing the caller.

  Currently, composite values instantiated based on database columns are frozen (addressing the first issue) and assigned compositve values are duplicated and the duplicate is frozen (addressing the second issue).

  Greg Navis

• Fix redundant updates to the column insensitivity cache

  Fixed redundant queries checking column capability for insensitive comparison.

  Phil Pirozhkov

• Allow disabling methods generated by ActiveRecord.enum.

  Alfred Dominic

• Avoid validating belongs_to association if it has not changed.

  Previously, when updating a record, Active Record will perform an extra query to check for the presence of belongs_to associations (if the presence is configured to be mandatory), even if that attribute hasn't changed.

  Currently, only belongs_to-related columns are checked for presence. It is possible to have orphaned records with this approach. To avoid this problem, you need to use a foreign key.

  This behavior can be controlled by configuration:

  config.active_record.belongs_to_required_validates_foreign_key = false

  and will be disabled by default with config.load_defaults 7.1.

  fatkodima

• has_one and belongs_to associations now define a reset_association method on the owner model (where association is the name of the association). This method unloads the cached associate record, if any, and causes the next access to query it from the database.

  George Claghorn

• Allow per attribute setting of YAML permitted classes (safe load) and unsafe load.

  Carlos Palhares

• Add a build persistence method

  Provides a wrapper for new, to provide feature parity with creates ability to create multiple records from an array of hashes, using the same notation as the build method on associations.

  Sean Denny

• Raise on assignment to readonly attributes

  class Post < ActiveRecord::Base
    attr_readonly :content
  end
  Post.create!(content: "cannot be updated")
  post.content # "cannot be updated"
  post.content = "something else" # => ActiveRecord::ReadonlyAttributeError

  Previously, assignment would succeed but silently not write to the database.

  This behavior can be controlled by configuration:

  config.active_record.raise_on_assign_to_attr_readonly = true

  and will be enabled by default with config.load_defaults 7.1.

  Alex Ghiculescu, Hartley McGuire

• Allow unscoping of preload and eager_load associations

  Added the ability to unscope preload and eager_load associations just like includes, joins, etc. See ActiveRecord::QueryMethods::VALID_UNSCOPING_VALUES for the full list of supported unscopable scopes.

  query.unscope(:eager_load, :preload).group(:id).select(:id)

  David Morehouse

• Add automatic filtering of encrypted attributes on inspect

  This feature is enabled by default but can be disabled with

  config.active_record.encryption.add_to_filter_parameters = false

  Hartley McGuire

• Clear locking column on #dup

  This change fixes not to duplicate locking_column like id and timestamps.

  car = Car.create!
  car.touch
  car.lock_version #=> 1
  car.dup.lock_version #=> 0
  

  Shouichi Kamiya, Seonggi Yang, Ryohei UEDA

• Invalidate transaction as early as possible

  After rescuing a TransactionRollbackError exception Rails invalidates transactions earlier in the flow allowing the framework to skip issuing the ROLLBACK statement in more cases. Only affects adapters that have savepoint_errors_invalidate_transactions? configured as true, which at this point is only applicable to the mysql2 adapter.

  Nikita Vasilevsky

• Allow configuring columns list to be used in SQL queries issued by an ActiveRecord::Base object

  It is now possible to configure columns list that will be used to build an SQL query clauses when updating, deleting or reloading an ActiveRecord::Base object

  class Developer < ActiveRecord::Base
    query_constraints :company_id, :id
  end
  developer = Developer.first.update(name: "Bob")
  # => UPDATE "developers" SET "name" = 'Bob' WHERE "developers"."company_id" = 1 AND "developers"."id" = 1

  Nikita Vasilevsky

• Adds validate to foreign keys and check constraints in schema.rb

  Previously, schema.rb would not record if validate: false had been used when adding a foreign key or check constraint, so restoring a database from the schema could result in foreign keys or check constraints being incorrectly validated.

  Tommy Graves

• Adapter #execute methods now accept an allow_retry option. When set to true, the SQL statement will be retried, up to the database's configured connection_retries value, upon encountering connection-related errors.

  Adrianna Chang

• Only trigger after_commit :destroy callbacks when a database row is deleted.

  This prevents after_commit :destroy callbacks from being triggered again when destroy is called multiple times on the same record.

  Ben Sheldon

• Fix ciphertext_for for yet-to-be-encrypted values.

  Previously, ciphertext_for returned the cleartext of values that had not yet been encrypted, such as with an unpersisted record:

  Post.encrypts :body
  
  post = Post.create!(body: "Hello")
  post.ciphertext_for(:body)
  # => "{\"p\":\"abc..."
  
  post.body = "World"
  post.ciphertext_for(:body)
  # => "World"

  Now, ciphertext_for will always return the ciphertext of encrypted attributes:

  Post.encrypts :body
  
  post = Post.create!(body: "Hello")
  post.ciphertext_for(:body)
  # => "{\"p\":\"abc..."
  
  post.body = "World"
  post.ciphertext_for(:body)
  # => "{\"p\":\"xyz..."

  Jonathan Hefner

• Fix a bug where using groups and counts with long table names would return incorrect results.

  Shota Toguchi, Yusaku Ono

• Fix encryption of column default values.

  Previously, encrypted attributes that used column default values appeared to be encrypted on create, but were not:

  Book.encrypts :name
  
  book = Book.create!
  book.name
  # => "<untitled>"
  book.name_before_type_cast
  # => "{\"p\":\"abc..."
  book.reload.name_before_type_cast
  # => "<untitled>"

  Now, attributes with column default values are encrypted:

  Book.encrypts :name
  
  book = Book.create!
  book.name
  # => "<untitled>"
  book.name_before_type_cast
  # => "{\"p\":\"abc..."
  book.reload.name_before_type_cast
  # => "{\"p\":\"abc..."

  Jonathan Hefner

• Deprecate delegation from Base to connection_handler.

  Calling Base.clear_all_connections!, Base.clear_active_connections!, Base.clear_reloadable_connections! and Base.flush_idle_connections! is deprecated. Please call these methods on the connection handler directly. In future Rails versions, the delegation from Base to the connection_handler will be removed.

  Eileen M. Uchitelle

• Allow ActiveRecord::QueryMethods#reselect to receive hash values, similar to ActiveRecord::QueryMethods#select

  Sampat Badhe

• Validate options when managing columns and tables in migrations.

  If an invalid option is passed to a migration method like create_table and add_column, an error will be raised instead of the option being silently ignored. Validation of the options will only be applied for new migrations that are created.

  Guo Xiang Tan, George Wambold

• Update query log tags to use the SQLCommenter format by default. See #46179

  To opt out of SQLCommenter-formatted query log tags, set config.active_record.query_log_tags_format = :legacy. By default, this is set to :sqlcommenter.

  Modulitos and Iheanyi

• Allow any ERB in the database.yml when creating rake tasks.

  Any ERB can be used in database.yml even if it accesses environment configurations.

  Deprecates config.active_record.suppress_multiple_database_warning.

  Eike Send

• Add table to error for duplicate column definitions.

  If a migration defines duplicate columns for a table, the error message shows which table it concerns.

  Petrik de Heus

• Fix erroneous nil default precision on virtual datetime columns.

  Prior to this change, virtual datetime columns did not have the same default precision as regular datetime columns, resulting in the following being erroneously equivalent:

  t.virtual :name, type: datetime,                 as: "expression"
  t.virtual :name, type: datetime, precision: nil, as: "expression"
  

  This change fixes the default precision lookup, so virtual and regular datetime column default precisions match.

  Sam Bostock

• Use connection from #with_raw_connection in #quote_string.

  This ensures that the string quoting is wrapped in the reconnect and retry logic that #with_raw_connection offers.

  Adrianna Chang

• Add expires_at option to signed_id.

  Shouichi Kamiya

• Allow applications to set retry deadline for query retries.

  Building on the work done in #44576 and #44591, we extend the logic that automatically reconnects database connections to take into account a timeout limit. We won't retry a query if a given amount of time has elapsed since the query was first attempted. This value defaults to nil, meaning that all retryable queries are retried regardless of time elapsed, but this can be changed via the retry_deadline option in the database config.

  Adrianna Chang

• Fix a case where the query cache can return wrong values. See #46044

  Aaron Patterson

• Support MySQL's ssl-mode option for MySQLDatabaseTasks.

  Verifying the identity of the database server requires setting the ssl-mode option to VERIFY_CA or VERIFY_IDENTITY. This option was previously ignored for MySQL database tasks like creating a database and dumping the structure.

  Petrik de Heus

• Move ActiveRecord::InternalMetadata to an independent object.

  ActiveRecord::InternalMetadata no longer inherits from ActiveRecord::Base and is now an independent object that should be instantiated with a connection. This class is private and should not be used by applications directly. If you want to interact with the schema migrations table, please access it on the connection directly, for example: ActiveRecord::Base.connection.schema_migration.

  Eileen M. Uchitelle

• Deprecate quoting ActiveSupport::Duration as an integer

  Using ActiveSupport::Duration as an interpolated bind parameter in a SQL string template is deprecated. To avoid this warning, you should explicitly convert the duration to a more specific database type. For example, if you want to use a duration as an integer number of seconds:

  Record.where("duration = ?", 1.hour.to_i)
  

  If you want to use a duration as an ISO 8601 string:

  Record.where("duration = ?", 1.hour.iso8601)
  

  Aram Greenman

• Allow QueryMethods#in_order_of to order by a string column name.

  Post.in_order_of("id", [4,2,3,1]).to_a
  Post.joins(:author).in_order_of("authors.name", ["Bob", "Anna", "John"]).to_a

  Igor Kasyanchuk

• Move ActiveRecord::SchemaMigration to an independent object.

  ActiveRecord::SchemaMigration no longer inherits from ActiveRecord::Base and is now an independent object that should be instantiated with a connection. This class is private and should not be used by applications directly. If you want to interact with the schema migrations table, please access it on the connection directly, for example: ActiveRecord::Base.connection.schema_migration.

  Eileen M. Uchitelle

• Deprecate all_connection_pools and make connection_pool_list more explicit.

  Following on #45924 all_connection_pools is now deprecated. connection_pool_list will either take an explicit role or applications can opt into the new behavior by passing :all.

  Eileen M. Uchitelle

• Fix connection handler methods to operate on all pools.

  active_connections?, clear_active_connections!, clear_reloadable_connections!, clear_all_connections!, and flush_idle_connections! now operate on all pools by default. Previously they would default to using the current_role or :writing role unless specified.

  Eileen M. Uchitelle

• Allow ActiveRecord::QueryMethods#select to receive hash values.

  Currently, select might receive only raw sql and symbols to define columns and aliases to select.

  With this change we can provide hash as argument, for example:

  Post.joins(:comments).select(posts: [:id, :title, :created_at], comments: [:id, :body, :author_id])
  #=> "SELECT \"posts\".\"id\", \"posts\".\"title\", \"posts\".\"created_at\", \"comments\".\"id\", \"comments\".\"body\", \"comments\".\"author_id\"
  #   FROM \"posts\" INNER JOIN \"comments\" ON \"comments\".\"post_id\" = \"posts\".\"id\""
  
  Post.joins(:comments).select(posts: { id: :post_id, title: :post_title }, comments: { id: :comment_id, body: :comment_body })
  #=> "SELECT posts.id as post_id, posts.title as post_title, comments.id as comment_id, comments.body as comment_body
  #    FROM \"posts\" INNER JOIN \"comments\" ON \"comments\".\"post_id\" = \"posts\".\"id\""

  Oleksandr Holubenko, Josef Šimánek, Jean Boussier

• Adapts virtual attributes on ActiveRecord::Persistence#becomes.

  When source and target classes have a different set of attributes adapts attributes such that the extra attributes from target are added.

  class Person < ApplicationRecord
  end
  
  class WebUser < Person
    attribute :is_admin, :boolean
    after_initialize :set_admin
  
    def set_admin
      write_attribute(:is_admin, email =~ /@ourcompany\.com$/)
    end
  end
  
  person = Person.find_by(email: "email@ourcompany.com")
  person.respond_to? :is_admin
  # => false
  person.becomes(WebUser).is_admin?
  # => true

  Jacopo Beschi, Sampson Crowley

• Fix ActiveRecord::QueryMethods#in_order_of to include nils, to match the behavior of Enumerable#in_order_of.

  For example, Post.in_order_of(:title, [nil, "foo"]) will now include posts with nil titles, the same as Post.all.to_a.in_order_of(:title, [nil, "foo"]).

  fatkodima

• Optimize add_timestamps to use a single SQL statement.

  add_timestamps :my_table

  Now results in the following SQL:

  ALTER TABLE "my_table" ADD COLUMN "created_at" datetime(6) NOT NULL, ADD COLUMN "updated_at" datetime(6) NOT NULL

  Iliana Hadzhiatanasova

• Add drop_enum migration command for PostgreSQL

  This does the inverse of create_enum. Before dropping an enum, ensure you have dropped columns that depend on it.

  Alex Ghiculescu

• Adds support for if_exists option when removing a check constraint.

  The remove_check_constraint method now accepts an if_exists option. If set to true an error won't be raised if the check constraint doesn't exist.

  Margaret Parsa and Aditya Bhutani

• find_or_create_by now try to find a second time if it hits a unicity constraint.

  find_or_create_by always has been inherently racy, either creating multiple duplicate records or failing with ActiveRecord::RecordNotUnique depending on whether a proper unicity constraint was set.

  create_or_find_by was introduced for this use case, however it's quite wasteful when the record is expected to exist most of the time, as INSERT require to send more data than SELECT and require more work from the database. Also on some databases it can actually consume a primary key increment which is undesirable.

  So for case where most of the time the record is expected to exist, find_or_create_by can be made race-condition free by re-trying the find if the create failed with ActiveRecord::RecordNotUnique. This assumes that the table has the proper unicity constraints, if not, find_or_create_by will still lead to duplicated records.

  Jean Boussier, Alex Kitchens

• Introduce a simpler constructor API for ActiveRecord database adapters.

  Previously the adapter had to know how to build a new raw connection to support reconnect, but also expected to be passed an initial already- established connection.

  When manually creating an adapter instance, it will now accept a single config hash, and only establish the real connection on demand.

  Matthew Draper

• Avoid redundant SELECT 1 connection-validation query during DB pool checkout when possible.

  If the first query run during a request is known to be idempotent, it can be used directly to validate the connection, saving a network round-trip.

  Matthew Draper

• Automatically reconnect broken database connections when safe, even mid-request.

  When an error occurs while attempting to run a known-idempotent query, and not inside a transaction, it is safe to immediately reconnect to the database server and try again, so this is now the default behavior.

  This new default should always be safe -- to support that, it's consciously conservative about which queries are considered idempotent -- but if necessary it can be disabled by setting the connection_retries connection option to 0.

  Matthew Draper

• Avoid removing a PostgreSQL extension when there are dependent objects.

  Previously, removing an extension also implicitly removed dependent objects. Now, this will raise an error.

  You can force removing the extension:

  disable_extension :citext, force: :cascade

  Fixes #29091.

  fatkodima

• Allow nested functions as safe SQL string

  Michael Siegfried

• Allow destroy_association_async_job= to be configured with a class string instead of a constant.

  Defers an autoloading dependency between ActiveRecord::Base and ActiveJob::Base and moves the configuration of ActiveRecord::DestroyAssociationAsyncJob from ActiveJob to ActiveRecord.

  Deprecates ActiveRecord::ActiveJobRequiredError and now raises a NameError if the job class is unloadable or an ActiveRecord::ConfigurationError if dependent: :destroy_async is declared on an association but there is no job class configured.

  Ben Sheldon

• Fix ActiveRecord::Store to serialize as a regular Hash

  Previously it would serialize as an ActiveSupport::HashWithIndifferentAccess which is wasteful and cause problem with YAML safe_load.

  Jean Boussier

• Add timestamptz as a time zone aware type for PostgreSQL

  This is required for correctly parsing timestamp with time zone values in your database.

  If you don't want this, you can opt out by adding this initializer:

  ActiveRecord::Base.time_zone_aware_types -= [:timestamptz]

  Alex Ghiculescu

• Add new ActiveRecord::Base.generates_token_for API.

  Currently, signed_id fulfills the role of generating tokens for e.g. resetting a password. However, signed IDs cannot reflect record state, so if a token is intended to be single-use, it must be tracked in a database at least until it expires.

  With generates_token_for, a token can embed data from a record. When using the token to fetch the record, the data from the token and the current data from the record will be compared. If the two do not match, the token will be treated as invalid, the same as if it had expired. For example:

  class User < ActiveRecord::Base
    has_secure_password
  
    generates_token_for :password_reset, expires_in: 15.minutes do
      # A password's BCrypt salt changes when the password is updated.
      # By embedding (part of) the salt in a token, the token will
      # expire when the password is updated.
      BCrypt::Password.new(password_digest).salt[-10..]
    end
  end
  
  user = User.first
  token = user.generate_token_for(:password_reset)
  
  User.find_by_token_for(:password_reset, token) # => user
  
  user.update!(password: "new password")
  User.find_by_token_for(:password_reset, token) # => nil

  Jonathan Hefner

• Optimize Active Record batching for whole table iterations.

  Previously, in_batches got all the ids and constructed an IN-based query for each batch. When iterating over the whole tables, this approach is not optimal as it loads unneeded ids and IN queries with lots of items are slow.

  Now, whole table iterations use range iteration (id >= x AND id <= y) by default which can make iteration several times faster. E.g., tested on a PostgreSQL table with 10 million records: querying (253s vs 30s), updating (288s vs 124s), deleting (268s vs 83s).

  Only whole table iterations use this style of iteration by default. You can disable this behavior by passing use_ranges: false. If you iterate over the table and the only condition is, e.g., archived_at: nil (and only a tiny fraction of the records are archived), it makes sense to opt in to this approach:

  Project.where(archived_at: nil).in_batches(use_ranges: true) do |relation|
    # do something
  end

  See #45414 for more details.

  fatkodima

• .with query method added. Construct common table expressions with ease and get ActiveRecord::Relation back.

  Post.with(posts_with_comments: Post.where("comments_count > ?", 0))
  # => ActiveRecord::Relation
  # WITH posts_with_comments AS (SELECT * FROM posts WHERE (comments_count > 0)) SELECT * FROM posts

  Vlado Cingel

• Don't establish a new connection if an identical pool exists already.

  Previously, if establish_connection was called on a class that already had an established connection, the existing connection would be removed regardless of whether it was the same config. Now if a pool is found with the same values as the new connection, the existing connection will be returned instead of creating a new one.

  This has a slight change in behavior if application code is depending on a new connection being established regardless of whether it's identical to an existing connection. If the old behavior is desirable, applications should call ActiveRecord::Base#remove_connection before establishing a new one. Calling establish_connection with a different config works the same way as it did previously.

  Eileen M. Uchitelle

• Update db:prepare task to load schema when an uninitialized database exists, and dump schema after migrations.

  Ben Sheldon

• Fix supporting timezone awareness for tsrange and tstzrange array columns.

  # In database migrations
  add_column :shops, :open_hours, :tsrange, array: true
  # In app config
  ActiveRecord::Base.time_zone_aware_types += [:tsrange]
  # In the code times are properly converted to app time zone
  Shop.create!(open_hours: [Time.current..8.hour.from_now])

  Wojciech Wnętrzak

• Introduce strategy pattern for executing migrations.

  By default, migrations will use a strategy object that delegates the method to the connection adapter. Consumers can implement custom strategy objects to change how their migrations run.

  Adrianna Chang

• Add adapter option disallowing foreign keys

  This adds a new option to be added to database.yml which enables skipping foreign key constraints usage even if the underlying database supports them.

  Usage:

  development:
      <<: *default
      database: storage/development.sqlite3
      foreign_keys: false

  Paulo Barros

• Add configurable deprecation warning for singular associations

  This adds a deprecation warning when using the plural name of a singular associations in where. It is possible to opt into the new more performant behavior with config.active_record.allow_deprecated_singular_associations_name = false

  Adam Hess

• Run transactional callbacks on the freshest instance to save a given record within a transaction.

  When multiple Active Record instances change the same record within a transaction, Rails runs after_commit or after_rollback callbacks for only one of them. config.active_record.run_commit_callbacks_on_first_saved_instances_in_transaction was added to specify how Rails chooses which instance receives the callbacks. The framework defaults were changed to use the new logic.

  When config.active_record.run_commit_callbacks_on_first_saved_instances_in_transaction is true, transactional callbacks are run on the first instance to save, even though its instance state may be stale.

  When it is false, which is the new framework default starting with version 7.1, transactional callbacks are run on the instances with the freshest instance state. Those instances are chosen as follows:

  • In general, run transactional callbacks on the last instance to save a given record within the transaction.
  • There are two exceptions:
    • If the record is created within the transaction, then updated by another instance, after_create_commit callbacks will be run on the second instance. This is instead of the after_update_commit callbacks that would naively be run based on that instance’s state.
    • If the record is destroyed within the transaction, then after_destroy_commit callbacks will be fired on the last destroyed instance, even if a stale instance subsequently performed an update (which will have affected 0 rows).

  Cameron Bothner and Mitch Vollebregt

• Enable strict strings mode for SQLite3Adapter.

  Configures SQLite with a strict strings mode, which disables double-quoted string literals.

  SQLite has some quirks around double-quoted string literals. It first tries to consider double-quoted strings as identifier names, but if they don't exist it then considers them as string literals. Because of this, typos can silently go unnoticed. For example, it is possible to create an index for a non existing column. See SQLite documentation for more details.

  If you don't want this behavior, you can disable it via:

  # config/application.rb
  config.active_record.sqlite3_adapter_strict_strings_by_default = false

  Fixes #27782.

  fatkodima, Jean Boussier

• Resolve issue where a relation cache_version could be left stale.

  Previously, when reset was called on a relation object it did not reset the cache_versions ivar. This led to a confusing situation where despite having the correct data the relation still reported a stale cache_version.

  Usage:

  developers = Developer.all
  developers.cache_version
  
  Developer.update_all(updated_at: Time.now.utc + 1.second)
  
  developers.cache_version # Stale cache_version
  developers.reset
  developers.cache_version # Returns the current correct cache_version

  Fixes #45341.

  Austen Madden

• Add support for exclusion constraints (PostgreSQL-only).

  add_exclusion_constraint :invoices, "daterange(start_date, end_date) WITH &&", using: :gist, name: "invoices_date_overlap"
  remove_exclusion_constraint :invoices, name: "invoices_date_overlap"

  See PostgreSQL's CREATE TABLE ... EXCLUDE ... documentation for more on exclusion constraints.

  Alex Robbin

• change_column_null raises if a non-boolean argument is provided

  Previously if you provided a non-boolean argument, change_column_null would treat it as truthy and make your column nullable. This could be surprising, so now the input must be either true or false.

  change_column_null :table, :column, true # good
  change_column_null :table, :column, false # good
  change_column_null :table, :column, from: true, to: false # raises (previously this made the column nullable)

  Alex Ghiculescu

• Enforce limit on table names length.

  Fixes #45130.

  fatkodima

• Adjust the minimum MariaDB version for check constraints support.

  Eddie Lebow

• Fix Hstore deserialize regression.

  edsharp

• Add validity for PostgreSQL indexes.

  connection.index_exists?(:users, :email, valid: true)
  connection.indexes(:users).select(&:valid?)

  fatkodima

• Fix eager loading for models without primary keys.

  Anmol Chopra, Matt Lawrence, and Jonathan Hefner

• Avoid validating a unique field if it has not changed and is backed by a unique index.

  Previously, when saving a record, Active Record will perform an extra query to check for the uniqueness of each attribute having a uniqueness validation, even if that attribute hasn't changed. If the database has the corresponding unique index, then this validation can never fail for persisted records, and we could safely skip it.

  fatkodima

• Stop setting sql_auto_is_null

  Since version 5.5 the default has been off, we no longer have to manually turn it off.

  Adam Hess

• Fix touch to raise an error for readonly columns.

  fatkodima

• Add ability to ignore tables by regexp for SQL schema dumps.

  ActiveRecord::SchemaDumper.ignore_tables = [/^_/]

  fatkodima

• Avoid queries when performing calculations on contradictory relations.

  Previously calculations would make a query even when passed a contradiction, such as User.where(id: []).count. We no longer perform a query in that scenario.

  This applies to the following calculations: count, sum, average, minimum and maximum

  Luan Vieira, John Hawthorn and Daniel Colson

• Allow using aliased attributes with insert_all/upsert_all.

  class Book < ApplicationRecord
    alias_attribute :title, :name
  end
  
  Book.insert_all [{ title: "Remote", author_id: 1 }], returning: :title

  fatkodima

• Support encrypted attributes on columns with default db values.

  This adds support for encrypted attributes defined on columns with default values. It will encrypt those values at creation time. Before, it would raise an error unless config.active_record.encryption.support_unencrypted_data was true.

  Jorge Manrubia and Dima Fatko

• Allow overriding reading_request? in DatabaseSelector::Resolver

  The default implementation checks if a request is a get? or head?, but you can now change it to anything you like. If the method returns true, Resolver#read gets called meaning the request could be served by the replica database.

  Alex Ghiculescu

• Remove ActiveRecord.legacy_connection_handling.

  Eileen M. Uchitelle

• rails db:schema:{dump,load} now checks ENV["SCHEMA_FORMAT"] before config

  Since rails db:structure:{dump,load} was deprecated there wasn't a simple way to dump a schema to both SQL and Ruby formats. You can now do this with an environment variable. For example:

  SCHEMA_FORMAT=sql rake db:schema:dump
  

  Alex Ghiculescu

• Fixed MariaDB default function support.

  Defaults would be written wrong in "db/schema.rb" and not work correctly if using db:schema:load. Further more the function name would be added as string content when saving new records.

  kaspernj

• Add active_record.destroy_association_async_batch_size configuration

  This allows applications to specify the maximum number of records that will be destroyed in a single background job by the dependent: :destroy_async association option. By default, the current behavior will remain the same: when a parent record is destroyed, all dependent records will be destroyed in a single background job. If the number of dependent records is greater than this configuration, the records will be destroyed in multiple background jobs.

  Nick Holden

• Fix remove_foreign_key with :if_exists option when foreign key actually exists.

  fatkodima

• Remove --no-comments flag in structure dumps for PostgreSQL

  This broke some apps that used custom schema comments. If you don't want comments in your structure dump, you can use:

  ActiveRecord::Tasks::DatabaseTasks.structure_dump_flags = ['--no-comments']

  Alex Ghiculescu

• Reduce the memory footprint of fixtures accessors.

  Until now fixtures accessors were eagerly defined using define_method. So the memory usage was directly dependent of the number of fixtures and test suites.

  Instead fixtures accessors are now implemented with method_missing, so they incur much less memory and CPU overhead.

  Jean Boussier

• Fix config.active_record.destroy_association_async_job configuration

  config.active_record.destroy_association_async_job should allow applications to specify the job that will be used to destroy associated records in the background for has_many associations with the dependent: :destroy_async option. Previously, that was ignored, which meant the default ActiveRecord::DestroyAssociationAsyncJob always destroyed records in the background.

  Nick Holden

• Fix change_column_comment to preserve column's AUTO_INCREMENT in the MySQL adapter

  fatkodima

• Fix quoting of ActiveSupport::Duration and Rational numbers in the MySQL adapter.

  Kevin McPhillips

• Allow column name with COLLATE (e.g., title COLLATE "C") as safe SQL string

  Shugo Maeda

• Permit underscores in the VERSION argument to database rake tasks.

  Eddie Lebow

• Reversed the order of INSERT statements in structure.sql dumps

  This should decrease the likelihood of merge conflicts. New migrations will now be added at the top of the list.

  For existing apps, there will be a large diff the next time structure.sql is generated.

  Alex Ghiculescu, Matt Larraz

• Fix PG.connect keyword arguments deprecation warning on ruby 2.7

  Fixes #44307.

  Nikita Vasilevsky

• Fix dropping DB connections after serialization failures and deadlocks.

  Prior to 6.1.4, serialization failures and deadlocks caused rollbacks to be issued for both real transactions and savepoints. This breaks MySQL which disallows rollbacks of savepoints following a deadlock.

  6.1.4 removed these rollbacks, for both transactions and savepoints, causing the DB connection to be left in an unknown state and thus discarded.

  These rollbacks are now restored, except for savepoints on MySQL.

  Thomas Morgan

• Make ActiveRecord::ConnectionPool Fiber-safe

  When ActiveSupport::IsolatedExecutionState.isolation_level is set to :fiber, the connection pool now supports multiple Fibers from the same Thread checking out connections from the pool.

  Alex Matchneer

• Add update_attribute! to ActiveRecord::Persistence

  Similar to update_attribute, but raises ActiveRecord::RecordNotSaved when a before_* callback throws :abort.

  class Topic < ActiveRecord::Base
    before_save :check_title
  
    def check_title
      throw(:abort) if title == "abort"
    end
  end
  
  topic = Topic.create(title: "Test Title")
  # #=> #<Topic title: "Test Title">
  topic.update_attribute!(:title, "Another Title")
  # #=> #<Topic title: "Another Title">
  topic.update_attribute!(:title, "abort")
  # raises ActiveRecord::RecordNotSaved

  Drew Tempelmeyer

• Avoid loading every record in ActiveRecord::Relation#pretty_print

  # Before
  pp Foo.all # Loads the whole table.
  
  # After
  pp Foo.all # Shows 10 items and an ellipsis.

  Ulysse Buonomo

• Change QueryMethods#in_order_of to drop records not listed in values.

  in_order_of now filters down to the values provided, to match the behavior of the Enumerable version.

  Kevin Newton

• Allow named expression indexes to be revertible.

  Previously, the following code would raise an error in a reversible migration executed while rolling back, due to the index name not being used in the index removal.

  add_index(:settings, "(data->'property')", using: :gin, name: :index_settings_data_property)

  Fixes #43331.

  Oliver Günther

• Fix incorrect argument in PostgreSQL structure dump tasks.

  Updating the --no-comment argument added in Rails 7 to the correct --no-comments argument.

  Alex Dent

• Fix migration compatibility to create SQLite references/belongs_to column as integer when migration version is 6.0.

  Reference/belongs_to in migrations with version 6.0 were creating columns as bigint instead of integer for the SQLite Adapter.

  Marcelo Lauxen

• Fix QueryMethods#in_order_of to handle empty order list.

  Post.in_order_of(:id, []).to_a

  Also more explicitly set the column as secondary order, so that any other value is still ordered.

  Jean Boussier

• Fix quoting of column aliases generated by calculation methods.

  Since the alias is derived from the table name, we can't assume the result is a valid identifier.

  class Test < ActiveRecord::Base
    self.table_name = '1abc'
  end
  Test.group(:id).count
  # syntax error at or near "1" (ActiveRecord::StatementInvalid)
  # LINE 1: SELECT COUNT(*) AS count_all, "1abc"."id" AS 1abc_id FROM "1...

  Jean Boussier

• Add authenticate_by when using has_secure_password.

  authenticate_by is intended to replace code like the following, which returns early when a user with a matching email is not found:

  User.find_by(email: "...")&.authenticate("...")

  Such code is vulnerable to timing-based enumeration attacks, wherein an attacker can determine if a user account with a given email exists. After confirming that an account exists, the attacker can try passwords associated with that email address from other leaked databases, in case the user re-used a password across multiple sites (a common practice). Additionally, knowing an account email address allows the attacker to attempt a targeted phishing ("spear phishing") attack.

  authenticate_by addresses the vulnerability by taking the same amount of time regardless of whether a user with a matching email is found:

  User.authenticate_by(email: "...", password: "...")

  Jonathan Hefner

Please check 7-0-stable for previous changes.