CHANGELOG.md

• create_savepoint, rollback_to_savepoint and release_savepoint accept a savepoint name.

  Yves Senn

• Make next_migration_number accessible for third party generators.

  Yves Senn

• Objects intiantiated using a null relationship will now retain the attributes of the where clause.

  Fixes: #11676, #11675, #11376

  Paul Nikitochkin, Peter Brown, Nthalk

• Fixed ActiveRecord::Associations::CollectionAssociation#find when using has_many association with :inverse_of and finding an array of one element, it should return an array of one element too.

  arthurnn

• Callbacks on has_many should access the in memory parent if a inverse_of is set.

  arthurnn

• ActiveRecord::ConnectionAdapters.string_to_time respects string with timezone (e.g. Wed, 04 Sep 2013 20:30:00 JST).

  Fixes: #12278

  kennyj

• Calling update_attributes will now throw an ArgumentError whenever it gets a nil argument. More specifically, it will throw an error if the argument that it gets passed does not respond to to stringify_keys.

  Example:

  @my_comment.update_attributes(nil)  # => raises ArgumentError
  

  John Wang

• Deprecate quoted_locking_column method, which isn't used anywhere.

  kennyj

• Migration dump UUID default functions to schema.rb.

  Fixes #10751.

  kennyj

• Fixed a bug in ActiveRecord::Associations::CollectionAssociation#find_by_scan when using has_many association with :inverse_of option and UUID primary key.

  Fixes #10450.

  kennyj

• ActiveRecord::Base#<=> has been removed. Primary keys may not be in order, or even be numbers, so sorting by id doesn't make sense. Please use sort_by and specify the attribute you wish to sort with. For example, change:

  Post.all.to_a.sort

  to:

  Post.all.to_a.sort_by(&:id)

  Aaron Patterson

• Fix: joins association, with defined in the scope block constraints by using several where constraints and at least of them is not Arel::Nodes::Equality, generates invalid SQL expression.

  Fixes: #11963

  Paul Nikitochkin

• Deprecate the delegation of Array bang methods for associations. To use them, instead first call #to_a on the association to access the array to be acted on.

  Ben Woosley

• CollectionAssociation#first/#last (e.g. has_many) use a LIMITed query to fetch results rather than loading the entire collection.

  Lann Martin

• Make possible to run SQLite rake tasks without the Rails constant defined.

  Damien Mathieu

• Allow Relation#from to accept other relations with bind values.

  Ryan Wallace

• Fix inserts with prepared statements disabled.

  Fixes #12023.

  Rafael Mendonça França

• Setting a has_one association on a new record no longer causes an empty transaction.

  Dylan Thacker-Smith

• Fix AR::Relation#merge sometimes failing to preserve readonly(false) flag.

  thedarkone

• Re-use order argument pre-processing for reorder.

  Paul Nikitochkin

• Fix PredicateBuilder so polymorphic association keys in where clause can accept objects other than direct descendants of ActiveRecord::Base (decorated models, for example).

  Mikhail Dieterle

• PostgreSQL adapter recognizes negative money values formatted with parentheses (eg. ($1.25) # => -1.25)). Fixes #11899.

  Yves Senn

• Stop interpreting SQL 'string' columns as :string type because there is no common STRING datatype in SQL.

  Ben Woosley

• ActiveRecord::FinderMethods#exists? returns true/false in all cases.

  Xavier Noria

• Assign inet/cidr attribute with nil value for invalid address.

  Example:

  record = User.new
  record.logged_in_from_ip # is type of an inet or a cidr
  
  # Before:
  record.logged_in_from_ip = 'bad ip address' # raise exception
  
  # After:
  record.logged_in_from_ip = 'bad ip address' # do not raise exception
  record.logged_in_from_ip # => nil
  record.logged_in_from_ip_before_type_cast # => 'bad ip address'
  

  Paul Nikitochkin

• add_to_target now accepts a second optional skip_callbacks argument

  If truthy, it will skip the :before_add and :after_add callbacks.

  Ben Woosley

• Fix interactions between :before_add callbacks and nested attributes assignment of has_many associations, when the association was not yet loaded:

  • A :before_add callback was being called when a nested attributes assignment assigned to an existing record.

  • Nested Attributes assignment did not affect the record in the association target when a :before_add callback triggered the loading of the association

  Jörg Schray

• Allow enable_extension migration method to be revertible.

  Eric Tipton

• Type cast hstore values on write, so that the value is consistent with reading from the database.

  Example:

  x = Hstore.new tags: {"bool" => true, "number" => 5}
  
  # Before:
  x.tags # => {"bool" => true, "number" => 5}
  
  # After:
  x.tags # => {"bool" => "true", "number" => "5"}
  

  Yves Senn , Severin Schoepke

• Fix multidimensional PG arrays containing non-string items.

  Yves Senn

• Load fixtures from linked folders.

  Kassio Borges

• Create a directory for sqlite3 file if not present on the system.

  Richard Schneeman

• Removed redundant override of xml column definition for PG, in order to use xml column type instead of text.

  Paul Nikitochkin, Michael Nikitochkin

• Revert ActiveRecord::Relation#order change that make new order prepend the old one.

  Before:

  User.order("name asc").order("created_at desc")
  # SELECT * FROM users ORDER BY created_at desc, name asc
  

  After:

  User.order("name asc").order("created_at desc")
  # SELECT * FROM users ORDER BY name asc, created_at desc
  

  This also affects order defined in default_scope or any kind of associations.

• Add ability to define how a class is converted to Arel predicates. For example, adding a very vendor specific regex implementation:

  regex_handler = proc do |column, value|
    Arel::Nodes::InfixOperation.new('~', column, value.source)
  end
  ActiveRecord::PredicateBuilder.register_handler(Regexp, regex_handler)
  

  Sean Griffin & @joannecheng

• Don't allow quote_value to be called without a column.

  Some adapters require column information to do their job properly. By enforcing the provision of the column for this internal method we ensure that those using adapters that require column information will always get the proper behavior.

  Ben Woosley

• When using optimistic locking, update was not passing the column to quote_value to allow the connection adapter to properly determine how to quote the value. This was affecting certain databases that use specific column types.

  Fixes: #6763

  Alfred Wong

• rescue from all exceptions in ConnectionManagement#call

  Fixes #11497

  As ActiveRecord::ConnectionAdapters::ConnectionManagement middleware does not rescue from Exception (but only from StandardError), the Connection Pool quickly runs out of connections when multiple erroneous Requests come in right after each other.

  Rescuing from all exceptions and not just StandardError, fixes this behaviour.

  Vipul A M

• change_column for PostgreSQL adapter respects the :array option.

  Yves Senn

• Remove deprecation warning from attribute_missing for attributes that are columns.

  Arun Agrawal

• Remove extra decrement of transaction deep level.

  Fixes: #4566

  Paul Nikitochkin

• Reset @column_defaults when assigning locking_column. We had a potential problem. For example:

  class Post < ActiveRecord::Base self.column_defaults # if we call this unintentionally before setting locking_column ... self.locking_column = 'my_locking_column' end

  Post.column_defaults["my_locking_column"] => nil # expected value is 0 !

  kennyj

• Remove extra select and update queries on save/touch/destroy ActiveRecord model with belongs to reflection with option touch: true.

  Fixes: #11288

  Paul Nikitochkin

• Remove deprecated nil-passing to the following SchemaCache methods: primary_keys, tables, columns and columns_hash.

  Yves Senn

• Remove deprecated block filter from ActiveRecord::Migrator#migrate.

  Yves Senn

• Remove deprecated String constructor from ActiveRecord::Migrator.

  Yves Senn

• Remove deprecated scope use without passing a callable object.

  Arun Agrawal

• Remove deprecated transaction_joinable= in favor of begin_transaction with :joinable option.

  Arun Agrawal

• Remove deprecated decrement_open_transactions.

  Arun Agrawal

• Remove deprecated increment_open_transactions.

  Arun Agrawal

• Remove deprecated PostgreSQLAdapter#outside_transaction? method. You can use #transaction_open? instead.

  Yves Senn

• Remove deprecated ActiveRecord::Fixtures.find_table_name in favor of ActiveRecord::Fixtures.default_fixture_model_name.

  Vipul A M

• Removed deprecated columns_for_remove from SchemaStatements.

  Neeraj Singh

• Remove deprecated SchemaStatements#distinct.

  Francesco Rodriguez

• Move deprecated ActiveRecord::TestCase into the rails test suite. The class is no longer public and is only used for internal Rails tests.

  Yves Senn

• Removed support for deprecated option :restrict for :dependent in associations.

  Neeraj Singh

• Removed support for deprecated delete_sql in associations.

  Neeraj Singh

• Removed support for deprecated insert_sql in associations.

  Neeraj Singh

• Removed support for deprecated finder_sql in associations.

  Neeraj Singh

• Support array as root element in JSON fields.

  Alexey Noskov & Francesco Rodriguez

• Removed support for deprecated counter_sql in associations.

  Neeraj Singh

• Do not invoke callbacks when delete_all is called on collection.

  Method delete_all should not be invoking callbacks and this feature was deprecated in Rails 4.0. This is being removed. delete_all will continue to honor the :dependent option. However if :dependent value is :destroy then the default deletion strategy for that collection will be applied.

  User can also force a deletion strategy by passing parameter to delete_all. For example you can do @post.comments.delete_all(:nullify) .

  Neeraj Singh

• Calling default_scope without a proc will now raise ArgumentError.

  Neeraj Singh

• Removed deprecated method type_cast_code from Column.

  Neeraj Singh

• Removed deprecated options delete_sql and insert_sql from HABTM association.

  Removed deprecated options finder_sql and counter_sql from collection association.

  Neeraj Singh

• Remove deprecated ActiveRecord::Base#connection method. Make sure to access it via the class.

  Yves Senn

• Remove deprecation warning for auto_explain_threshold_in_seconds.

  Yves Senn

• Remove deprecated :distinct option from Relation#count.

  Yves Senn

• Removed deprecated methods partial_updates, partial_updates? and partial_updates=.

  Neeraj Singh

• Removed deprecated method scoped

  Neeraj Singh

• Removed deprecated method default_scopes?

  Neeraj Singh

• Remove implicit join references that were deprecated in 4.0.

  Example:

  # before with implicit joins
  Comment.where('posts.author_id' => 7)
  
  # after
  Comment.references(:posts).where('posts.author_id' => 7)
  

  Yves Senn

• Apply default scope when joining associations. For example:

  class Post < ActiveRecord::Base
    default_scope -> { where published: true }
  end
  
  class Comment
    belongs_to :post
  end
  

  When calling Comment.joins(:post), we expect to receive only comments on published posts, since that is the default scope for posts.

  Before this change, the default scope from Post was not applied, so we'd get comments on unpublished posts.

  Jon Leighton

• Remove activerecord-deprecated_finders as a dependency

  Łukasz Strzałkowski

• Remove Oracle / Sqlserver / Firebird database tasks that were deprecated in 4.0.

  kennyj

• find_each now returns an Enumerator when called without a block, so that it can be chained with other Enumerable methods.

  Ben Woosley

• ActiveRecord::Result.each now returns an Enumerator when called without a block, so that it can be chained with other Enumerable methods.

  Ben Woosley

• Flatten merged join_values before building the joins.

  While joining_values special treatment is given to string values. By flattening the array it ensures that string values are detected as strings and not arrays.

  Fixes #10669.

  Neeraj Singh and iwiznia

• Do not load all child records for inverse case.

  currently post.comments.find(Comment.first.id) would load all comments for the given post to set the inverse association.

  This has a huge performance penalty. Because if post has 100k records and all these 100k records would be loaded in memory even though the comment id was supplied.

  Fix is to use in-memory records only if loaded? is true. Otherwise load the records using full sql.

  Fixes #10509.

  Neeraj Singh

• inspect on Active Record model classes does not initiate a new connection. This means that calling inspect, when the database is missing, will no longer raise an exception. Fixes #10936.

  Example:

  Author.inspect # => "Author(no database connection)"
  

  Yves Senn

• Handle single quotes in PostgreSQL default column values. Fixes #10881.

  Dylan Markow

• Log the sql that is actually sent to the database.

  If I have a query that produces sql WHERE "users"."name" = 'a b' then in the log all the whitespace is being squeezed. So the sql that is printed in the log is WHERE "users"."name" = 'a b'.

  Do not squeeze whitespace out of sql queries. Fixes #10982.

  Neeraj Singh

• Fixture setup does no longer depend on ActiveRecord::Base.configurations. This is relevant when ENV["DATABASE_URL"] is used in place of a database.yml.

  Yves Senn

• Fix mysql2 adapter raises the correct exception when executing a query on a closed connection.

  Yves Senn

• Ambiguous reflections are on :through relationships are no longer supported. For example, you need to change this:

  class Author < ActiveRecord::Base
    has_many :posts
    has_many :taggings, :through => :posts
  end
  
  class Post < ActiveRecord::Base
    has_one :tagging
    has_many :taggings
  end
  
  class Tagging < ActiveRecord::Base
  end
  

  To this:

  class Author < ActiveRecord::Base
    has_many :posts
    has_many :taggings, :through => :posts, :source => :tagging
  end
  
  class Post < ActiveRecord::Base
    has_one :tagging
    has_many :taggings
  end
  
  class Tagging < ActiveRecord::Base
  end
  

  Aaron Patterson

• Remove column restrictions for count, let the database raise if the SQL is invalid. The previous behavior was untested and surprising for the user. Fixes #5554.

  Example:

  User.select("name, username").count
  # Before => SELECT count(*) FROM users
  # After => ActiveRecord::StatementInvalid
  
  # you can still use `count(:all)` to perform a query unrelated to the
  # selected columns
  User.select("name, username").count(:all) # => SELECT count(*) FROM users
  

  Yves Senn

• Rails now automatically detects inverse associations. If you do not set the :inverse_of option on the association, then Active Record will guess the inverse association based on heuristics.

  Note that automatic inverse detection only works on has_many, has_one, and belongs_to associations. Extra options on the associations will also prevent the association's inverse from being found automatically.

  The automatic guessing of the inverse association uses a heuristic based on the name of the class, so it may not work for all associations, especially the ones with non-standard names.

  You can turn off the automatic detection of inverse associations by setting the :inverse_of option to false like so:

  class Taggable < ActiveRecord::Base
    belongs_to :tag, inverse_of: false
  end
  

  John Wang

• Fix add_column with array option when using PostgreSQL. Fixes #10432

  Adam Anderson

• Usage of implicit_readonly is being removed. Please use readonlymethod explicitly to mark records asreadonly. Fixes #10615.

  Example:

  user = User.joins(:todos).select("users.*, todos.title as todos_title").readonly(true).first
  user.todos_title = 'clean pet'
  user.save! # will raise error
  

  Yves Senn

• Fix the :primary_key option for has_many associations. Fixes #10693.

  Yves Senn

• Fix bug where tiny types are incorrectly coerced as boolean when the length is more than 1.

  Fixes #10620.

  Aaron Patterson

• Also support extensions in PostgreSQL 9.1. This feature has been supported since 9.1.

  kennyj

• Deprecate ConnectionAdapters::SchemaStatements#distinct, as it is no longer used by internals.

  Ben Woosley

• Fix pending migrations error when loading schema and ActiveRecord::Base.table_name_prefix is not blank.

  Call assume_migrated_upto_version on connection to prevent it from first being picked up in method_missing.

  In the base class, Migration, method_missing expects the argument to be a table name, and calls proper_table_name on the arguments before sending to connection. If table_name_prefix or table_name_suffix is used, the schema version changes to prefix_version_suffix, breaking rake test:prepare.

  Fixes #10411.

  Kyle Stevens

• Method read_attribute_before_type_cast should accept input as symbol.

  Neeraj Singh

• Confirm a record has not already been destroyed before decrementing counter cache.

  Ben Tucker

• Fixed a bug in ActiveRecord#sanitize_sql_hash_for_conditions in which self.class is an argument to PredicateBuilder#build_from_hash causing PredicateBuilder to call non-existent method Class#reflect_on_association.

  Zach Ohlgren

• While removing index if column option is missing then raise IrreversibleMigration exception.

  Following code should raise IrreversibleMigration. But the code was failing since options is an array and not a hash.

  def change
    change_table :users do |t|
      t.remove_index [:name, :email]
    end
  end
  

  Fix was to check if the options is a Hash before operating on it.

  Fixes #10419.

  Neeraj Singh

• Do not overwrite manually built records during one-to-one nested attribute assignment

  For one-to-one nested associations, if you build the new (in-memory) child object yourself before assignment, then the NestedAttributes module will not overwrite it, e.g.:

  class Member < ActiveRecord::Base
    has_one :avatar
    accepts_nested_attributes_for :avatar
  
    def avatar
      super || build_avatar(width: 200)
    end
  end
  
  member = Member.new
  member.avatar_attributes = {icon: 'sad'}
  member.avatar.width # => 200
  

  Olek Janiszewski

• fixes bug introduced by #3329. Now, when autosaving associations, deletions happen before inserts and saves. This prevents a 'duplicate unique value' database error that would occur if a record being created had the same value on a unique indexed field as that of a record being destroyed.

  Johnny Holton

• Handle aliased attributes in ActiveRecord::Relation.

  When using symbol keys, ActiveRecord will now translate aliased attribute names to the actual column name used in the database:

  With the model

  class Topic
    alias_attribute :heading, :title
  end
  

  The call

  Topic.where(heading: 'The First Topic')
  

  should yield the same result as

  Topic.where(title: 'The First Topic')
  

  This also applies to ActiveRecord::Relation::Calculations calls such as Model.sum(:aliased) and Model.pluck(:aliased).

  This will not work with SQL fragment strings like Model.sum('DISTINCT aliased').

  Godfrey Chan

• Mute psql output when running rake db:schema:load.

  Godfrey Chan

• Trigger a save on has_one association=(associate) when the associate contents have changed.

  Fix #8856.

  Chris Thompson

• Abort a rake task when missing db/structure.sql like db:schema:load task.

  kennyj

• rake:db:test:prepare falls back to original environment after execution.

  Slava Markevich

Please check 4-0-stable for previous changes.