CHANGELOG.md

Rails 4.2.11.3 (May 15, 2020)

• No changes.

Rails 4.2.11.2 (May 15, 2020)

• No changes.

Rails 4.2.11.1 (March 11, 2019)

• No changes.

Rails 4.2.11 (November 27, 2018)

• No changes.

Rails 4.2.10 (September 27, 2017)

• Relation#joins is no longer affected by the target model's current_scope, with the exception of unscoped.

  Fixes #29338.

  Sean Griffin

Rails 4.2.9 (June 26, 2017)

• Fix regression caused by collection_singular_ids= ignoring different primary key on relationship.

  Nick Pezza

• Fix rake db:schema:load with subdirectories.

  Ryuta Kamizono

• Fix rake db:migrate:status with subdirectories.

  Ryuta Kamizono

• Fix regression of #1969 with SELECT aliases in HAVING clause.

  Eugene Kenny

• Fix wait_timeout to configurable for mysql2 adapter.

  Fixes #26556.

  Ryuta Kamizono

• Make table_name= reset current statement cache, so queries are not run against the previous table name.

  namusyaka

Rails 4.2.8 (February 21, 2017)

• Using a mysql2 connection after it fails to reconnect will now have an error message saying the connection is closed rather than an undefined method error message.

  Dylan Thacker-Smith

• Bust Model.attribute_names cache when resetting column information

  James Coleman

• Fix query caching when type information is reset

  Backports ancillary fix in 5.0.

  James Coleman

• Allow joins to be unscoped.

  Fixes #13775.

  Takashi Kokubun

• Hashes can once again be passed to setters of composed_of, if all of the mapping methods are methods implemented on Hash.

  Fixes #25978.

  Sean Griffin

Rails 4.2.7 (July 12, 2016)

• Inspecting an object with an associated array of over 10 elements no longer truncates the array, preventing inspect from looping infinitely in some cases.

  Kevin McPhillips

• Ensure hashes can be assigned to attributes created using composed_of. Fixes #25210.

  Sean Griffin

• Queries such as Computer.joins(:monitor).group(:status).count will now be interpreted as Computer.joins(:monitor).group('computers.status').count so that when Computer and Monitor have both status columns we don't have conflicts in projection.

  Rafael Sales

• ActiveRecord::Relation#count: raise an ArgumentError when finder options are specified or an ActiveRecord::StatementInvalid when an invalid type is provided for a column name (e.g. a Hash).

  Fixes #20434

  Konstantinos Rousis

• Correctly pass MySQL options when using structure_dump or structure_load

  Specifically, it fixes an issue when using SSL authentication.

  Alex Coomans

Rails 4.2.6 (March 07, 2016)

• Fix a bug where using t.foreign_key twice with the same to_table within the same table definition would only create one foreign key.

  George Millo

• Fix regression in dirty attribute tracking after #dup. Changes to the clone no longer show as changed attributes in the original object.

  Dominic Cleal

• Fix regression when loading fixture files with symbol keys.

  Closes #22584.

  Yves Senn

• Fix rake db:structure:dump on Postgres when multiple schemas are used.

  Fixes #22346.

  Nick Muerdter, ckoenig

• Introduce connection.data_sources and connection.data_source_exists?. These methods determine what relations can be used to back Active Record models (usually tables and views).

  Yves Senn, Matthew Draper

Rails 4.2.5.2 (February 26, 2016)

• No changes.

Rails 4.2.5.1 (January 25, 2015)

• No changes.

Rails 4.2.5 (November 12, 2015)

• No longer pass deprecated option -i to pg_dump.

  Paul Sadauskas

• Set scope.reordering_value to true if :reordering values are specified.

  Fixes #21886.

  Hiroaki Izu

• Avoid disabling errors on the PostgreSQL connection when enabling the standard_conforming_strings setting. Errors were previously disabled because the setting wasn't writable in Postgres 8.1 and didn't exist in earlier versions. Now Rails only supports Postgres 8.2+ we're fine to assume the setting exists. Disabling errors caused problems when using a connection pooling tool like PgBouncer because it's not guaranteed to have the same connection between calls to execute and it could leave the connection with errors disabled.

  Fixes #22101.

  Harry Marr

• Includes HABTM returns correct size now. It's caused by the join dependency only instantiates one HABTM object because the join table hasn't a primary key.

  Fixes #16032.

  Examples:

  before:
  
  Project.first.salaried_developers.size # => 3
  Project.includes(:salaried_developers).first.salaried_developers.size # => 1
  
  after:
  
  Project.first.salaried_developers.size # => 3
  Project.includes(:salaried_developers).first.salaried_developers.size # => 3
  

  Bigxiang

• Descriptive error message when fixtures contain a missing column.

  Closes #21201.

  Yves Senn

• bin/rake db:migrate uses ActiveRecord::Tasks::DatabaseTasks.migrations_paths instead of Migrator.migrations_paths.

  Tobias Bielohlawek

• Fix rewhere in a has_many association.

  Fixes #21955.

  Josh Branchaud, Kal

• Added run_cmd class method to ActiveRecord::Tasks::DatabaseTasks for drying up Kernel.system() calls within this namespace and to avoid shell expansion by using a paramter list instead of string as arguments for Kernel.system(). Thanks to Nate Berkopec for supply patch to get test units passing.

  Bryan Paxton

• Avoid leaking the first relation we call first on, per model.

  Fixes #21921.

  Matthew Draper, Jean Boussier

• Allow deserialization of Active Record models that were YAML encoded prior to Rails 4.2

  Sean Griffin

• Correctly apply unscope when preloading through associations.

  Jimmy Bourassa

• Ensure select quotes aliased attributes, even when using from.

  Fixes #21488

  Sean Griffin & @johanlunds

• Correct query for PostgreSQL 8.2 compatibility.

  Ben Murphy, Matthew Draper

• Uniqueness validator raises descriptive error when running on a persisted record without primary key.

  Closes #21304.

  Yves Senn

Rails 4.2.4 (August 24, 2015)

• Skip statement cache on through association reader.

  If the through class has default scopes we should skip the statement cache.

  Closes #20745.

  Rafael Mendonça França

• Fixes #19420. When generating schema.rb using Postgres BigInt[] data type the limit: 8 was not coming through. This caused it to become Int[] data type after doing a rebuild off of schema.rb.

  Jake Waller

• Fix state being carried over from previous transaction.

  Considering the following example where name is a required attribute. Before we had new_record? returning true for a persisted record:

  author = Author.create! name: 'foo'
  author.name = nil
  author.save        # => false
  author.new_record? # => true
  

  Fixes #20824.

  Roque Pinel

• Correctly ignore mark_for_destruction when autosave isn't set to true when validating associations.

  Fixes #20882.

  Sean Griffin

• Fix through associations using scopes having the scope merged multiple times.

  Fixes #20721. Fixes #20727.

  Sean Griffin

• ActiveRecord::Base.dump_schema_after_migration applies migration tasks other than db:migrate. (eg. db:rollback, db:migrate:dup, ...)

  Fixes #20743.

  Yves Senn

• Correctly raise ActiveRecord::AssociationTypeMismatch when assigning a wrong type to a namespaced association.

  Fixes #20545.

  Diego Carrion

• Prevent error when using force_reload: true on an unassigned polymorphic belongs_to association.

  Fixes #20426.

  James Dabbs

Rails 4.2.3 (June 25, 2015)

• Let WITH queries (Common Table Expressions) be explainable.

  Vladimir Kochnev

• Fix n+1 query problem when eager loading nil associations (fixes #18312)

  Sammy Larbi

• Fixed an error which would occur in dirty checking when calling update_attributes from a getter.

  Fixes #20531.

  Sean Griffin

• Ensure symbols passed to ActiveRecord::Relation#select are always treated as columns.

  Fixes #20360.

  Sean Griffin

• Clear query cache when ActiveRecord::Base#reload is called.

  Shane Hender

• Pass :extend option for has_and_belongs_to_many associations to the underlying has_many :through.

  Jaehyun Shin

• Make unscope aware of "less than" and "greater than" conditions.

  TAKAHASHI Kazuaki

• Revert behavior of db:schema:load back to loading the full environment. This ensures that initializers are run.

  Fixes #19545.

  Yves Senn

• Fix missing index when using timestamps with the index option.

  The index option used with timestamps should be passed to both column definitions for created_at and updated_at rather than just the first.

  Paul Mucur

• Rename :class to :anonymous_class in association options.

  Fixes #19659.

  Andrew White

• Fixed a bug where uniqueness validations would error on out of range values, even if an validation should have prevented it from hitting the database.

  Andrey Voronkov

• Foreign key related methods in the migration DSL respect ActiveRecord::Base.pluralize_table_names = false.

  Fixes #19643.

  Mehmet Emin İNAÇ

• Reduce memory usage from loading types on pg.

  Fixes #19578.

  Sean Griffin

• Fix referencing wrong table aliases while joining tables of has many through association (only when calling calculation methods).

  Fixes #19276.

  pinglamb

• Don't attempt to update counter caches, when the column wasn't selected.

  Fixes #19437.

  Sean Griffin

• Correctly persist a serialized attribute that has been returned to its default value by an in-place modification.

  Fixes #19467.

  Matthew Draper

• Fix default format value in ActiveRecord::Tasks::DatabaseTasks#schema_file.

  James Cox

• Dont enroll records in the transaction if they dont have commit callbacks. That was causing a memory grow problem when creating a lot of records inside a transaction.

  Fixes #15549.

  Will Bryant, Aaron Patterson

• Correctly create through records when created on a has many through association when using where.

  Fixes #19073.

  Sean Griffin

Rails 4.2.2 (June 16, 2015)

• No Changes *

Rails 4.2.1 (March 19, 2015)

• Fixed ActiveRecord::Relation#becomes! and changed_attributes issues for type column

  Fixes #17139.

  Miklos Fazekas

• remove_reference with foreign_key: true removes the foreign key before removing the column. This fixes a bug where it was not possible to remove the column on MySQL.

  Fixes #18664.

  Yves Senn

• Add a :foreign_key option to references and associated migration methods. The model and migration generators now use this option, rather than the add_foreign_key form.

  Sean Griffin

• Fix rounding problem for PostgreSQL timestamp column.

  If timestamp column have the precision, it need to format according to the precision of timestamp column.

  Ryuta Kamizono

• Respect the database default charset for schema_migrations table.

  The charset of version column in schema_migrations table is depend on the database default charset and collation rather than the encoding of the connection.

  Ryuta Kamizono

• Respect custom primary keys for associations when calling Relation#where

  Fixes #18813.

  Sean Griffin

• Fixed several edge cases which could result in a counter cache updating twice or not updating at all for has_many and has_many :through.

  Fixes #10865.

  Sean Griffin

• Foreign keys added by migrations were given random, generated names. This meant a different structure.sql would be generated every time a developer ran migrations on their machine.

  The generated part of foreign key names is now a hash of the table name and column name, which is consistent every time you run the migration.

  Chris Sinjakli

• Fixed ActiveRecord::Relation#group method when argument is SQL reserved key word:

  SplitTest.group(:key).count Property.group(:value).count

  Bogdan Gusiev

• Don't define autosave association callbacks twice from accepts_nested_attributes_for.

  Fixes #18704.

  Sean Griffin

• Integer types will no longer raise a RangeError when assigning an attribute, but will instead raise when going to the database.

  Fixes several vague issues which were never reported directly. See the commit message from the commit which added this line for some examples.

  Sean Griffin

• Values which would error while being sent to the database (such as an ASCII-8BIT string with invalid UTF-8 bytes on Sqlite3), no longer error on assignment. They will still error when sent to the database, but you are given the ability to re-assign it to a valid value.

  Fixes #18580.

  Sean Griffin

• Don't remove join dependencies in Relation#exists?

  Fixes #18632.

  Sean Griffin

• Invalid values assigned to a JSON column are assumed to be nil.

  Fixes #18629.

  Sean Griffin

• No longer issue deprecation warning when including a scope with extensions. Previously every scope with extension methods was transformed into an instance dependent scope. Including such a scope would wrongfully issue a deprecation warning. This is no longer the case.

  Fixes #18467.

  Yves Senn

• Correctly use the type provided by serialize when updating records using optimistic locking.

  Fixes #18385.

  Sean Griffin

• attribute_will_change! will no longer cause non-persistable attributes to be sent to the database.

  Fixes #18407.

  Sean Griffin

• Format the datetime string according to the precision of the datetime field.

  Incompatible to rounding behavior between MySQL 5.6 and earlier.

  In 5.5, when you insert 2014-08-17 12:30:00.999999 the fractional part is ignored. In 5.6, it's rounded to 2014-08-17 12:30:01:

  http://bugs.mysql.com/bug.php?id=68760

  Ryuta Kamizono

• Allow precision option for MySQL datetimes.

  Ryuta Kamizono

• Clear query cache on rollback.

  Florian Weingarten

• Fixed setting of foreign_key for through associations while building of new record.

  Fixes #12698.

  Ivan Antropov

• Fixed automatic inverse_of for models nested in module.

  Andrew McCloud

• Fix reaping_frequency option when the value is a string.

  This usually happens when it is configured using DATABASE_URL.

  korbin

• Fix error message when trying to create an associated record and the foreign key is missing.

  Before this fix the following exception was being raised:

  NoMethodError: undefined method `val' for #<Arel::Nodes::BindParam:0x007fc64d19c218>
  

  Now the message is:

  ActiveRecord::UnknownAttributeError: unknown attribute 'foreign_key' for Model.
  

  Rafael Mendonça França

• Fix change detection problem for PostgreSQL bytea type and ArgumentError: string contains null byte exception with pg-0.18.

  Fixes #17680.

  Lars Kanis

• When a table has a composite primary key, the primary_key method for SQLite3 and PostgreSQL adapters was only returning the first field of the key. Ensures that it will return nil instead, as Active Record doesn't support composite primary keys.

  Fixes #18070.

  arthurnn

• Ensure first! and friends work on loaded associations.

  Fixes #18237.

  Sean Griffin

• Dump the default nil for PostgreSQL UUID primary key.

  Ryuta Kamizono

• Don't raise when writing an attribute with an out-of-range datetime passed by the user.

  Grey Baker

• Fixes bug with 'ActiveRecord::Type::Numeric' that causes negative values to be marked as having changed when set to the same negative value.

  Fixes #18161.

  Daniel Fox

Rails 4.2.0 (December 20, 2014)

• Introduce force: :cascade option for create_table. Using this option will recreate tables even if they have dependent objects (like foreign keys). db/schema.rb now uses force: :cascade. This makes it possible to reload the schema when foreign keys are in place.

  Matthew Draper, Yves Senn

• db:schema:load and db:structure:load no longer purge the database before loading the schema. This is left for the user to do. db:test:prepare will still purge the database.

  Fixes #17945.

  Yves Senn

• Fix undesirable RangeError by Type::Integer. Add Type::UnsignedInteger.

  Ryuta Kamizono

• Add foreign_type option to has_one and has_many association macros.

  This option enables to define the column name of associated object's type for polymorphic associations.

  Ulisses Almeida, Kassio Borges

• add_timestamps and remove_timestamps now properly reversible with options.

  Noam Gagliardi-Rabinovich

• Bring back db:test:prepare to synchronize the test database schema.

  Manual synchronization using bin/rake db:test:prepare is required when a migration is rolled-back, edited and reapplied.

  ActiveRecord::Base.maintain_test_schema now uses db:test:prepare to synchronize the schema. Plugins can use this task as a hook to provide custom behavior after the schema has been loaded.

  NOTE: test:prepare runs before the schema is synchronized.

  Fixes #17171, #15787.

  Yves Senn

• Change reflections public api to return the keys as String objects.

  Fixes #16928.

  arthurnn

• Renaming a table in pg also renames the primary key index.

  Fixes #12856

  Sean Griffin

• Make it possible to access fixtures excluded by a default_scope.

  Yves Senn

• Fix preloading of associations with a scope containing joins along with conditions on the joined association.

  Siddharth Sharma

• Add Table#name to match TableDefinition#name.

  Cody Cutrer

• Cache CollectionAssociation#reader proxies separately before and after the owner has been saved so that the proxy is not cached without the owner's id.

  Ben Woosley

• ActiveRecord::ReadOnlyRecord now has a descriptive message.

  Franky W.

• Fix preloading of associations which unscope a default scope.

  Fixes #11036.

  Byron Bischoff

• Added SchemaDumper support for tables with jsonb columns.

  Ted O'Meara

• Deprecate sanitize_sql_hash_for_conditions without replacement. Using a Relation for performing queries and updates is the prefered API.

  Sean Griffin

• Queries now properly type cast values that are part of a join statement, even when using type decorators such as serialize.

  Melanie Gilman & Sean Griffin

• MySQL enum type lookups, with values matching another type, no longer result in an endless loop.

  Fixes #17402.

  Yves Senn

• Raise ArgumentError when the body of a scope is not callable.

  Mauro George

• Use type column first in multi-column indexes created with add-reference.

  Derek Prior

• Fix Relation.rewhere to work with Range values.

  Dan Olson

• AR::UnknownAttributeError now includes the class name of a record.

  User.new(name: "Yuki Nishijima", project_attributes: {name: "kaminari"})
  # => ActiveRecord::UnknownAttributeError: unknown attribute 'name' for User.
  

  Yuki Nishijima

• Fix a regression causing after_create callbacks to run before associated records are autosaved.

  Fixes #17209.

  Agis Anastasopoulos

• Honor overridden rack.test in Rack environment for the connection management middleware.

  Simon Eskildsen

• Add a truncate method to the connection.

  Aaron Patterson

• Don't autosave unchanged has_one through records.

  Alan Kennedy, Steve Parrington

• Do not dump foreign keys for ignored tables.

  Yves Senn

• PostgreSQL adapter correctly dumps foreign keys targeting tables outside the schema search path.

  Fixes #16907.

  Matthew Draper, Yves Senn

• When a thread is killed, rollback the active transaction, instead of committing it during the stack unwind. Previously, we could commit half- completed work. This fix only works for Ruby 2.0+; on 1.9, we can't distinguish a thread kill from an ordinary non-local (block) return, so must default to committing.

  Chris Hanks

• A NullRelation should represent nothing. This fixes a bug where Comment.where(post_id: Post.none) returned a non-empty result.

  Fixes #15176.

  Matthew Draper, Yves Senn

• Include default column limits in schema.rb. Allows defaults to be changed in the future without affecting old migrations that assumed old defaults.

  Jeremy Kemper

• MySQL: schema.rb now includes TEXT and BLOB column limits.

  Jeremy Kemper

• MySQL: correct LONGTEXT and LONGBLOB limits from 2GB to their true 4GB.

  Jeremy Kemper

• SQLite3Adapter now checks for views in table_exists?. Fixes #14041.

  Girish Sonawane

• Introduce connection.supports_views? to check whether the current adapter has support for SQL views. Connection adapters should define this method.

  Yves Senn

• Allow included modules to override association methods.

  Fixes #16684.

  Yves Senn

• Schema loading rake tasks (like db:schema:load and db:setup) maintain the database connection to the current environment.

  Fixes #16757.

  Joshua Cody, Yves Senn

• MySQL: set the connection collation along with the charset.

  Sets the connection collation to the database collation configured in database.yml. Otherwise, SET NAMES utf8mb4 will use the default collation for that charset (utf8mb4_general_ci) when you may have chosen a different collation, like utf8mb4_unicode_ci.

  This only applies to literal string comparisons, not column values, so it is unlikely to affect you.

  Jeremy Kemper

• default_sequence_name from the PostgreSQL adapter returns a String.

  Yves Senn

• Fix a regression where whitespaces were stripped from DISTINCT queries in PostgreSQL.

  Agis Anastasopoulos

  Fixes #16623.

• Fix has_many :through relation merging failing when dynamic conditions are passed as a lambda with an arity of one.

  Fixes #16128.

  Agis Anastasopoulos

• Fix Relation#exists? to work with polymorphic associations.

  Fixes #15821.

  Kassio Borges

• Currently, Active Record rescues any errors raised within after_rollback/after_create callbacks and prints them to the logs. Future versions of Rails will not rescue these errors anymore and just bubble them up like the other callbacks.

  This commit adds an opt-in flag to enable not rescuing the errors.

  Example:

  # Do not swallow errors in after_commit/after_rollback callbacks.
  config.active_record.raise_in_transactional_callbacks = true
  

  Fixes #13460.

  arthurnn

• Fix an issue where custom accessor methods (such as those generated by enum) with the same name as a global method are incorrectly overridden when subclassing.

  Fixes #16288.

  Godfrey Chan

• *_was and changes now work correctly for in-place attribute changes as well.

  Sean Griffin

• Fix regression on after_commit that did not fire with nested transactions.

  Fixes #16425.

  arthurnn

• Do not try to write timestamps when a table has no timestamps columns.

  Fixes #8813.

  Sergey Potapov

• index_exists? with :name option does verify specified columns.

  Example:

  add_index :articles, :title, name: "idx_title"
  
  # Before:
  index_exists? :articles, :title, name: "idx_title" # => `true`
  index_exists? :articles, :body, name: "idx_title" # => `true`
  
  # After:
  index_exists? :articles, :title, name: "idx_title" # => `true`
  index_exists? :articles, :body, name: "idx_title" # => `false`
  

  Yves Senn, Matthew Draper

• add_timestamps and t.timestamps now require you to pass the :null option. Not passing the option is deprecated but the default is still null: true. With Rails 5 this will change to null: false.

  Sean Griffin

• When calling update_columns on a record that is not persisted, the error message now reflects whether that object is a new record or has been destroyed.

  Lachlan Sylvester

• Define id_was to get the previous value of the primary key.

  Currently when we call id_was and we have a custom primary key name, Active Record will return the current value of the primary key. This makes it impossible to correctly do an update operation if you change the id.

  Fixes #16413.

  Rafael Mendonça França

• Deprecate DatabaseTasks.load_schema to act on the current connection. Use .load_schema_current instead. In the future load_schema will require the configuration to act on as an argument.

  Yves Senn

• Fix automatic maintaining test schema to properly handle sql structure schema format.

  Fixes #15394.

  Wojciech Wnętrzak

• Fix type casting to Decimal from Float with large precision.

  Tomohiro Hashidate

• Deprecate Reflection#source_macro

  Reflection#source_macro is no longer needed in Active Record source so it has been deprecated. Code that used source_macro was removed in #16353.

  Eileen M. Uchtitelle, Aaron Patterson

• No verbose backtrace by db:drop when database does not exist.

  Fixes #16295.

  Kenn Ejima

• Add support for PostgreSQL JSONB.

  Example:

  create_table :posts do |t|
    t.jsonb :meta_data
  end
  

  Philippe Creux, Chris Teague

• db:purge with MySQL respects Rails.env.

  Yves Senn

• change_column_default :table, :column, nil with PostgreSQL will issue a DROP DEFAULT instead of a DEFAULT NULL query.

  Fixes #16261.

  Matthew Draper, Yves Senn

• Allow to specify a type for the foreign key column in references and add_reference.

  Example:

  change_table :vehicle do |t|
    t.references :station, type: :uuid
  end
  

  Andrey Novikov, Łukasz Sarnacki

• create_join_table removes a common prefix when generating the join table. This matches the existing behavior of HABTM associations.

  Fixes #13683.

  Stefan Kanev

• Do not swallow errors on compute_type when having a bad alias_method on a class.

  arthurnn

• PostgreSQL invalid uuid are convert to nil.

  Abdelkader Boudih

• Restore 4.0 behavior for using serialize attributes with JSON as coder.

  With 4.1.x, serialize started returning a string when JSON was passed as the second attribute. It will now return a hash as per previous versions.

  Example:

  class Post < ActiveRecord::Base
    serialize :comment, JSON
  end
  
  class Comment
    include ActiveModel::Model
    attr_accessor :category, :text
  end
  
  post = Post.create!
  post.comment = Comment.new(category: "Animals", text: "This is a comment about squirrels.")
  post.save!
  
  # 4.0
  post.comment # => {"category"=>"Animals", "text"=>"This is a comment about squirrels."}
  
  # 4.1 before
  post.comment # => "#<Comment:0x007f80ab48ff98>"
  
  # 4.1 after
  post.comment # => {"category"=>"Animals", "text"=>"This is a comment about squirrels."}
  

  When using JSON as the coder in serialize, Active Record will use the new ActiveRecord::Coders::JSON coder which delegates its dump/load to ActiveSupport::JSON.encode/decode. This ensures special objects are dumped correctly using the #as_json hook.

  To keep the previous behaviour, supply a custom coder instead (example).

  Fixes #15594.

  Jenn Cooper

• Do not use RENAME INDEX syntax for MariaDB 10.0.

  Fixes #15931.

  Jeff Browning

• Calling #empty? on a has_many association would use the value from the counter cache if one exists.

  David Verhasselt

• Fix the schema dump generated for tables without constraints and with primary key with default value of custom PostgreSQL function result.

  Fixes #16111.

  Andrey Novikov

• Fix the SQL generated when a delete_all is run on an association to not produce an IN statements.

  Before:

  UPDATE "categorizations" SET "category_id" = NULL WHERE "categorizations"."category_id" = 1 AND "categorizations"."id" IN (1, 2)

  After:

  UPDATE "categorizations" SET "category_id" = NULL WHERE "categorizations"."category_id" = 1

  Eileen M. Uchitelle, Aaron Patterson

• Avoid type casting boolean and ActiveSupport::Duration values to numeric values for string columns. Otherwise, in some database, the string column values will be coerced to a numeric allowing false or 0.seconds match any string starting with a non-digit.

  Example:

  App.where(apikey: false) # => SELECT * FROM users WHERE apikey = '0'
  

  Dylan Thacker-Smith

• Add a :required option to singular associations, providing a nicer API for presence validations on associations.

  Sean Griffin

• Fix an error in reset_counters when associations have select scope. (Call to count generated invalid SQL.)

  Cade Truitt

• After a successful reload, new_record? is always false.

  Fixes #12101.

  Matthew Draper

• PostgreSQL renaming table doesn't attempt to rename non existent sequences.

  Abdelkader Boudih

• Move 'dependent: :destroy' handling for belongs_to from before_destroy to after_destroy callback chain

  Fixes #12380.

  Ivan Antropov

• Detect in-place modifications on String attributes.

  Before this change, an attribute modified in-place had to be marked as changed in order for it to be persisted in the database. Now it is no longer required.

  Before:

  user = User.first
  user.name << ' Griffin'
  user.name_will_change!
  user.save
  user.reload.name # => "Sean Griffin"
  

  After:

  user = User.first
  user.name << ' Griffin'
  user.save
  user.reload.name # => "Sean Griffin"
  

  Sean Griffin

• Add ActiveRecord::Base#validate! that raises RecordInvalid if the record is invalid.

  Bogdan Gusiev, Marc Schütz

• Support for adding and removing foreign keys. Foreign keys are now a part of schema.rb. This is supported by Mysql2Adapter, MysqlAdapter and PostgreSQLAdapter.

  Many thanks to Matthew Higgins for laying the foundation with his work on foreigner.

  Example:

  # within your migrations:
  add_foreign_key :articles, :authors
  remove_foreign_key :articles, :authors
  

  Yves Senn

• Fix subtle bugs regarding attribute assignment on models with no primary key. 'id' will no longer be part of the attributes hash.

  Sean Griffin

• Deprecate automatic counter caches on has_many :through. The behavior was broken and inconsistent.

  Sean Griffin

• preload preserves readonly flag for associations.

  See #15853.

  Yves Senn

• Assume numeric types have changed if they were assigned to a value that would fail numericality validation, regardless of the old value. Previously this would only occur if the old value was 0.

  Example:

  model = Model.create!(number: 5)
  model.number = '5wibble'
  model.number_changed? # => true
  

  Fixes #14731.

  Sean Griffin

• reload no longer merges with the existing attributes. The attribute hash is fully replaced. The record is put into the same state as it would be with Model.find(model.id).

  Sean Griffin

• The object returned from select_all must respond to column_types. If this is not the case a NoMethodError is raised.

  Sean Griffin

• Detect in-place modifications of PG array types

  Sean Griffin

• Add bin/rake db:purge task to empty the current database.

  Yves Senn

• Deprecate serialized_attributes without replacement.

  Sean Griffin

• Correctly extract IPv6 addresses from DATABASE_URI: the square brackets are part of the URI structure, not the actual host.

  Fixes #15705.

  Andy Bakun, Aaron Stone

• Ensure both parent IDs are set on join records when both sides of a through association are new.

  Sean Griffin

• ActiveRecord::Dirty now detects in-place changes to mutable values. Serialized attributes on ActiveRecord models will no longer save when unchanged.

  Fixes #8328.

  Sean Griffin

• Pluck now works when selecting columns from different tables with the same name.

  Fixes #15649.

  Sean Griffin

• Remove cache_attributes and friends. All attributes are cached.

  Sean Griffin

• Remove deprecated method ActiveRecord::Base.quoted_locking_column.

  Akshay Vishnoi

• ActiveRecord::FinderMethods.find with block can handle proc parameter as Enumerable#find does.

  Fixes #15382.

  James Yang

• Make timezone aware attributes work with PostgreSQL array columns.

  Fixes #13402.

  Kuldeep Aggarwal, Sean Griffin

• ActiveRecord::SchemaMigration has no primary key regardless of the primary_key_prefix_type configuration.

  Fixes #15051.

  JoseLuis Torres, Yves Senn

• rake db:migrate:status works with legacy migration numbers like 00018_xyz.rb.

  Fixes #15538.

  Yves Senn

• Baseclass becomes! subclass.

  Before this change, a record which changed its STI type, could not be updated.

  Fixes #14785.

  Matthew Draper, Earl St Sauver, Edo Balvers

• Remove deprecated ActiveRecord::Migrator.proper_table_name. Use the proper_table_name instance method on ActiveRecord::Migration instead.

  Akshay Vishnoi

• Fix regression on eager loading association based on SQL query rather than existing column.

  Fixes #15480.

  Lauro Caetano, Carlos Antonio da Silva

• Deprecate returning nil from column_for_attribute when no column exists. It will return a null object in Rails 5.0

  Sean Griffin

• Implemented ActiveRecord::Base#pretty_print to work with PP.

  Ethan

• Preserve type when dumping PostgreSQL point, bit, bit varying and money columns.

  Yves Senn

• New records remain new after YAML serialization.

  Sean Griffin

• PostgreSQL support default values for enum types. Fixes #7814.

  Yves Senn

• PostgreSQL default_sequence_name respects schema. Fixes #7516.

  Yves Senn

• Fix columns_for_distinct of PostgreSQL adapter to work correctly with orders without sort direction modifiers.

  Nikolay Kondratyev

• PostgreSQL reset_pk_sequence! respects schemas. Fixes #14719.

  Yves Senn

• Keep PostgreSQL hstore and json attributes as Hash in @attributes. Fixes duplication in combination with store_accessor.

  Fixes #15369.

  Yves Senn

• rake railties:install:migrations respects the order of railties.

  Arun Agrawal

• Fix redefine a has_and_belongs_to_many inside inherited class Fixing regression case, where redefining the same has_and_belongs_to_many definition into a subclass would raise.

  Fixes #14983.

  arthurnn

• Fix has_and_belongs_to_many public reflection. When defining a has_and_belongs_to_many, internally we convert that to two has_many. But as reflections is a public API, people expect to see the right macro.

  Fixes #14682.

  arthurnn

• Fix serialization for records with an attribute named format.

  Fixes #15188.

  Godfrey Chan

• When a group is set, sum, size, average, minimum and maximum on a NullRelation should return a Hash.

  Kuldeep Aggarwal

• Fix serialized fields returning serialized data after being updated with update_column.

  Simon Hørup Eskildsen

• Fix polymorphic eager loading when using a String as foreign key.

  Fixes #14734.

  Lauro Caetano

• Change belongs_to touch to be consistent with timestamp updates

  If a model is set up with a belongs_to: touch relationship the parent record will only be touched if the record was modified. This makes it consistent with timestamp updating on the record itself.

  Brock Trappitt

• Fix the inferred table name of a has_and_belongs_to_many auxiliary table inside a schema.

  Fixes #14824.

  Eric Chahin

• Remove unused :timestamp type. Transparently alias it to :datetime in all cases. Fixes inconsistencies when column types are sent outside of ActiveRecord, such as for XML Serialization.

  Sean Griffin

• Fix bug that added table_name_prefix and table_name_suffix to extension names in PostgreSQL when migrating.

  Joao Carlos

• The :index option in migrations, which previously was only available for references, now works with any column types.

  Marc Schütz

• Add support for counter name to be passed as parameter on CounterCache::ClassMethods#reset_counters.

  jnormore

• Restrict deletion of record when using delete_all with uniq, group, having or offset.

  In these cases the generated query ignored them and that caused unintended records to be deleted.

  Fixes #11985.

  Leandro Facchinetti

• Floats with limit >= 25 that get turned into doubles in MySQL no longer have their limit dropped from the schema.

  Fixes #14135.

  Aaron Nelson

• Fix how to calculate associated class name when using namespaced has_and_belongs_to_many association.

  Fixes #14709.

  Kassio Borges

• ActiveRecord::Relation::Merger#filter_binds now compares equivalent symbols and strings in column names as equal.

  This fixes a rare case in which more bind values are passed than there are placeholders for them in the generated SQL statement, which can make PostgreSQL throw a StatementInvalid exception.

  Nat Budin

• Fix stored_attributes to correctly merge the details of stored attributes defined in parent classes.

  Fixes #14672.

  Brad Bennett, Jessica Yao, Lakshmi Parthasarathy

• change_column_default allows [] as argument to change_column_default.

  Fixes #11586.

  Yves Senn

• Handle name and "char" column types in the PostgreSQL adapter.

  name and "char" are special character types used internally by PostgreSQL and are used by internal system catalogs. These field types can sometimes show up in structure-sniffing queries that feature internal system structures or with certain PostgreSQL extensions.

  J Smith, Yves Senn

• Fix PostgreSQLAdapter::OID::Float#type_cast to convert Infinity and NaN PostgreSQL values into a native Ruby Float::INFINITY and Float::NAN

  Before:

  Point.create(value: 1.0/0)
  Point.last.value # => 0.0
  

  After:

  Point.create(value: 1.0/0)
  Point.last.value # => Infinity
  

  Innokenty Mikhailov

• Allow the PostgreSQL adapter to handle bigserial primary key types again.

  Fixes #10410.

  Patrick Robertson

• Deprecate joining, eager loading and preloading of instance dependent associations without replacement. These operations happen before instances are created. The current behavior is unexpected and can result in broken behavior.

  Fixes #15024.

  Yves Senn

• Fix has_and_belongs_to_many CollectionAssociation size calculations.

  has_and_belongs_to_many should fall back to using the normal CollectionAssociation's size calculation if the collection is not cached or loaded.

  Fixes #14913, #14914.

  Fred Wu

• Return a non zero status when running rake db:migrate:status and migration table does not exist.

  Paul B.

• Add support for module-level table_name_suffix in models.

  This makes table_name_suffix work the same way as table_name_prefix when using namespaced models.

  Jenner LaFave

• Revert the behaviour of ActiveRecord::Relation#join changed through 4.0 => 4.1 to 4.0.

  In 4.1.0 Relation#join is delegated to Arel#SelectManager. In 4.0 series it is delegated to Array#join.

  Bogdan Gusiev

• Log nil binary column values correctly.

  When an object with a binary column is updated with a nil value in that column, the SQL logger would throw an exception when trying to log that nil value. This only occurs when updating a record that already has a non-nil value in that column since an initial nil value isn't included in the SQL anyway (at least, when dirty checking is enabled.) The column's new value will now be logged as <NULL binary data> to parallel the existing <N bytes of binary data> for non-nil values.

  James Coleman

• Rails will now pass a custom validation context through to autosave associations in order to validate child associations with the same context.

  Fixes #13854.

  Eric Chahin, Aaron Nelson, Kevin Casey

• Stringify all variables keys of MySQL connection configuration.

  When sql_mode variable for MySQL adapters set in configuration as String was ignored and overwritten by strict mode option.

  Fixes #14895.

  Paul Nikitochkin

• Ensure SQLite3 statements are closed on errors.

  Fixes #13631.

  Timur Alperovich

• Give ActiveRecord::PredicateBuilder private methods the privacy they deserve.

  Hector Satre

• When using a custom join_table name on a habtm, rails was not saving it on Reflections. This causes a problem when rails loads fixtures, because it uses the reflections to set database with fixtures.

  Fixes #14845.

  Kassio Borges

• Reset the cache when modifying a Relation with cached Arel. Additionally display a warning message to make the user aware.

  Yves Senn

• PostgreSQL should internally use :datetime consistently for TimeStamp. Assures different spellings of timestamps are treated the same.

  Example:

  mytimestamp.simplified_type('timestamp without time zone')
  # => :datetime
  mytimestamp.simplified_type('timestamp(6) without time zone')
  # => also :datetime (previously would be :timestamp)
  

  See #14513.

  Jefferson Lai

• ActiveRecord::Base.no_touching no longer triggers callbacks or start empty transactions.

  Fixes #14841.

  Lucas Mazza

• Fix name collision with Array#select! with Relation#select!.

  Fixes #14752.

  Earl St Sauver

• Fix unexpected behavior for has_many :through associations going through a scoped has_many.

  If a has_many association is adjusted using a scope, and another has_many :through uses this association, then the scope adjustment is unexpectedly neglected.

  Fixes #14537.

  Jan Habermann

• @destroyed should always be set to false when an object is duped.

  Kuldeep Aggarwal

• Enable has_many associations to support irregular inflections.

  Fixes #8928.

  arthurnn, Javier Goizueta

• Fix count used with a grouping not returning a Hash.

  Fixes #14721.

  Eric Chahin

• sanitize_sql_like helper method to escape a string for safe use in an SQL LIKE statement.

  Example:

  class Article
    def self.search(term)
      where("title LIKE ?", sanitize_sql_like(term))
    end
  end
  
  Article.search("20% _reduction_")
  # => Query looks like "... title LIKE '20\% \_reduction\_' ..."
  

  Rob Gilson, Yves Senn

• Do not quote uuid default value on change_column.

  Fixes #14604.

  Eric Chahin

• The comparison between Relation and CollectionProxy should be consistent.

  Example:

  author.posts == Post.where(author_id: author.id)
  # => true
  Post.where(author_id: author.id) == author.posts
  # => true
  

  Fixes #13506.

  Lauro Caetano

• Calling delete_all on an unloaded CollectionProxy no longer generates an SQL statement containing each id of the collection:

  Before:

  DELETE FROM `model` WHERE `model`.`parent_id` = 1
  AND `model`.`id` IN (1, 2, 3...)
  

  After:

  DELETE FROM `model` WHERE `model`.`parent_id` = 1
  

  Eileen M. Uchitelle, Aaron Patterson

• Fix invalid SQL when aggregate methods (empty?, any?, count) used with select.

  Fixes #13648.

  Simon Woker

• PostgreSQL adapter only warns once for every missing OID per connection.

  Fixes #14275.

  Matthew Draper, Yves Senn

• PostgreSQL adapter automatically reloads it's type map when encountering unknown OIDs.

  Fixes #14678.

  Matthew Draper, Yves Senn

• Fix insertion of records via has_many :through association with scope.

  Fixes #3548.

  Ivan Antropov

• Auto-generate stable fixture UUIDs on PostgreSQL.

  Fixes #11524.

  Roderick van Domburg

• Fix a problem where an enum would overwrite values of another enum with the same name in an unrelated class.

  Fixes #14607.

  Evan Whalen

• PostgreSQL and SQLite string columns no longer have a default limit of 255.

  Fixes #13435, #9153.

  Vladimir Sazhin, Toms Mikoss, Yves Senn

• Make possible to have an association called records.

  Fixes #11645.

  prathamesh-sonpatki

• to_sql on an association now matches the query that is actually executed, where it could previously have incorrectly accrued additional conditions (e.g. as a result of a previous query). CollectionProxy now always defers to the association scope's arel method so the (incorrect) inherited one should be entirely concealed.

  Fixes #14003.

  Jefferson Lai

• Block a few default Class methods as scope name.

  For instance, this will raise:

  scope :public, -> { where(status: 1) }
  

  arthurnn

• Fix error when using with_options with lambda.

  Fixes #9805.

  Lauro Caetano

• Switch sqlite3:/// URLs (which were temporarily deprecated in 4.1) from relative to absolute.

  If you still want the previous interpretation, you should replace sqlite3:///my/path with sqlite3:my/path.

  Matthew Draper

• Treat blank UUID values as nil.

  Example:

  Sample.new(uuid_field: '') #=> <Sample id: nil, uuid_field: nil>
  

  Dmitry Lavrov

• Enable support for materialized views on PostgreSQL >= 9.3.

  Dave Lee

• The PostgreSQL adapter supports custom domains. Fixes #14305.

  Yves Senn

• PostgreSQL Column#type is now determined through the corresponding OID. The column types stay the same except for enum columns. They no longer have nil as type but enum.

  See #7814.

  Yves Senn

• Fix error when specifying a non-empty default value on a PostgreSQL array column.

  Fixes #10613.

  Luke Steensen

• Fix error where .persisted? throws SystemStackError for an unsaved model with a custom primary key that did not save due to validation error.

  Fixes #14393.

  Chris Finne

• Introduce validate as an alias for valid?.

  This is more intuitive when you want to run validations but don't care about the return value.

  Henrik Nyh

• Create indexes inline in CREATE TABLE for MySQL.

  This is important, because adding an index on a temporary table after it has been created would commit the transaction.

  It also allows creating and dropping indexed tables with fewer queries and fewer permissions required.

  Example:

  create_table :temp, temporary: true, as: "SELECT id, name, zip FROM a_really_complicated_query" do |t|
    t.index :zip
  end
  # => CREATE TEMPORARY TABLE temp (INDEX (zip)) AS SELECT id, name, zip FROM a_really_complicated_query
  

  Cody Cutrer, Steve Rice, Rafael Mendonça Franca

• Use singular table name in generated migrations when ActiveRecord::Base.pluralize_table_names is false.

  Fixes #13426.

  Kuldeep Aggarwal

• touch accepts many attributes to be touched at once.

  Example:

  # touches :signed_at, :sealed_at, and :updated_at/on attributes.
  Photo.last.touch(:signed_at, :sealed_at)
  

  James Pinto

• rake db:structure:dump only dumps schema information if the schema migration table exists.

  Fixes #14217.

  Yves Senn

• Reap connections that were checked out by now-dead threads, instead of waiting until they disconnect by themselves. Before this change, a suitably constructed series of short-lived threads could starve the connection pool, without ever having more than a couple alive at the same time.

  Matthew Draper

• pk_and_sequence_for now ensures that only the pg_depend entries pointing to pg_class, and thus only sequence objects, are considered.

  Josh Williams

• where.not adds references for includes like normal where calls do.

  Fixes #14406.

  Yves Senn

• Extend fixture $LABEL replacement to allow string interpolation.

  Example:

  martin:
    email: [email protected]
  
  users(:martin).email # => [email protected]
  

  Eric Steele

• Add support for Relation be passed as parameter on QueryCache#select_all.

  Fixes #14361.

  arthurnn

• Passing an Active Record object to find or exists? is now deprecated. Call .id on the object first.

  Aaron Patterson

• Only use BINARY for MySQL case sensitive uniqueness check when column has a case insensitive collation.

  Ryuta Kamizono

• Support for MySQL 5.6 fractional seconds.

  arthurnn, Tatsuhiko Miyagawa

• Support for PostgreSQL citext data type enabling case-insensitive where values without needing to wrap in UPPER/LOWER sql functions.

  Troy Kruthoff, Lachlan Sylvester

• Only save has_one associations if record has changes. Previously after save related callbacks, such as #after_commit, were triggered when the has_one object did not get saved to the db.

  Alan Kennedy

• Allow strings to specify the #order value.

  Example:

  Model.order(id: 'asc').to_sql == Model.order(id: :asc).to_sql
  

  Marcelo Casiraghi, Robin Dupret

• Dynamically register PostgreSQL enum OIDs. This prevents "unknown OID" warnings on enum columns.

  Dieter Komendera

• includes is able to detect the right preloading strategy when string joins are involved.

  Fixes #14109.

  Aaron Patterson, Yves Senn

• Fix error with validation with enum fields for records where the value for any enum attribute is always evaluated as 0 during uniqueness validation.

  Fixes #14172.

  Vilius Luneckas Ahmed AbouElhamayed

• before_add callbacks are fired before the record is saved on has_and_belongs_to_many associations and on has_many :through associations. Before this change, before_add callbacks would be fired before the record was saved on has_and_belongs_to_many associations, but not on has_many :through associations.

  Fixes #14144.

• Fix STI classes not defining an attribute method if there is a conflicting private method defined on its ancestors.

  Fixes #11569.

  Godfrey Chan

• Coerce strings when reading attributes. Fixes #10485.

  Example:

  book = Book.new(title: 12345)
  book.save!
  book.title # => "12345"
  

  Yves Senn

• Deprecate half-baked support for PostgreSQL range values with excluding beginnings. We currently map PostgreSQL ranges to Ruby ranges. This conversion is not fully possible because the Ruby range does not support excluded beginnings.

  The current solution of incrementing the beginning is not correct and is now deprecated. For subtypes where we don't know how to increment (e.g. #succ is not defined) it will raise an ArgumentException for ranges with excluding beginnings.

  Yves Senn

• Support for user created range types in PostgreSQL.

  Yves Senn

Please check 4-1-stable for previous changes.