1 files changed, 502 insertions, 10 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 3c4f06ccf8..fa2b7f0c0f 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,488 @@
+*   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*
+
+*   Autosave existing records on a has many through association when the parent
+    is new.
+
+    Fixes #19782.
+
+    *Sean Griffin*
+
+*   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*
+
+*   MySQL: `:charset` and `:collation` support for string and text columns.
+
+    Example:
+
+        create_table :foos do |t|
+          t.string :string_utf8_bin, charset: 'utf8', collation: 'utf8_bin'
+          t.text   :text_ascii,      charset: 'ascii'
+        end
+
+    *Ryuta Kamizono*
+
+*   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 PostgreSQL.
+
+    Fixes #19578.
+
+    *Sean Griffin*
+
+*   Add `config.active_record.warn_on_records_fetched_greater_than` option.
+
+    When set to an integer, a warning will be logged whenever a result set
+    larger than the specified size is returned by a query.
+
+    Fixes #16463.
+
+    *Jason Nochlin*
+
+*   Ignore `.psqlrc` when loading database structure.
+
+    *Jason Weathered*
+
+*   Fix referencing wrong table aliases while joining tables of has many through
+    association (only when calling calculation methods).
+
+    Fixes #19276.
+
+    *pinglamb*
+
+*   Correctly persist a serialized attribute that has been returned to
+    its default value by an in-place modification.
+
+    Fixes #19467.
+
+    *Matthew Draper*
+
+*   Fix generating the schema file when using PostgreSQL `BigInt[]` data type.
+    Previously the `limit: 8` was not coming through, and this caused it to
+    become `Int[]` data type after rebuilding from the schema.
+
+    Fixes #19420.
+
+    *Jake Waller*
+
+*   Reuse the `CollectionAssociation#reader` cache when the foreign key is
+    available prior to save.
+
+    *Ben Woosley*
+
+*   Add `config.active_record.dump_schemas` to fix `db:structure:dump`
+    when using schema_search_path and PostgreSQL extensions.
+
+    Fixes #17157.
+
+    *Ryan Wallace*
+
+*   Renaming `use_transactional_fixtures` to `use_transactional_tests` for clarity.
+
+    Fixes #18864.
+
+    *Brandon Weiss*
+
+*   Increase pg gem version requirement to `~> 0.18`. Earlier versions of the
+    pg gem are known to have problems with Ruby 2.2.
+
+    *Matt Brictson*
+
+*   Correctly dump `serial` and `bigserial`.
+
+    *Ryuta Kamizono*
+
+*   Fix default `format` value in `ActiveRecord::Tasks::DatabaseTasks#schema_file`.
+
+    *James Cox*
+
+*   Don't enroll records in the transaction if they don't have commit callbacks.
+    This was causing a memory leak when creating many 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*
+
+*   Add `SchemaMigration.create_table` support for any unicode charsets with MySQL.
+
+    *Ryuta Kamizono*
+
+*   PostgreSQL no longer disables user triggers if system triggers can't be
+    disabled. Disabling user triggers does not fulfill what the method promises.
+    Rails currently requires superuser privileges for this method.
+
+    If you absolutely rely on this behavior, consider patching
+    `disable_referential_integrity`.
+
+    *Yves Senn*
+
+*   Restore aborted transaction state when `disable_referential_integrity` fails
+    due to missing permissions.
+
+    *Toby Ovod-Everett*, *Yves Senn*
+
+*   In PostgreSQL, print a warning message if `disable_referential_integrity`
+    fails due to missing permissions.
+
+    *Andrey Nering*, *Yves Senn*
+
+*   Allow a `:limit` option for MySQL bigint primary key support.
+
+    Example:
+
+        create_table :foos, id: :primary_key, limit: 8 do |t|
+        end
+
+        # or
+
+        create_table :foos, id: false do |t|
+          t.primary_key :id, limit: 8
+        end
+
+    *Ryuta Kamizono*
+
+*   `belongs_to` will now trigger a validation error by default if the association is not present.
+    You can turn this off on a per-association basis with `optional: true`.
+    (Note this new default only applies to new Rails apps that will be generated with
+    `config.active_record.belongs_to_required_by_default = true` in initializer.)
+
+    *Josef Šimánek*
+
+*   Fixed ActiveRecord::Relation#becomes! and changed_attributes issues for type
+    columns.
+
+    Fixes #17139.
+
+    *Miklos Fazekas*
+
+*   Format the time string according to the precision of the time column.
+
+    *Ryuta Kamizono*
+
+*   Allow a `:precision` option for time type columns.
+
+    *Ryuta Kamizono*
+
+*   Add `ActiveRecord::Base.suppress` to prevent the receiver from being saved
+    during the given block.
+
+    For example, here's a pattern of creating notifications when new comments
+    are posted. (The notification may in turn trigger an email, a push
+    notification, or just appear in the UI somewhere):
+
+        class Comment < ActiveRecord::Base
+          belongs_to :commentable, polymorphic: true
+          after_create -> { Notification.create! comment: self,
+            recipients: commentable.recipients }
+        end
+
+    That's what you want the bulk of the time. A new comment creates a new
+    Notification. There may be edge cases where you don't want that, like
+    when copying a commentable and its comments, in which case write a
+    concern with something like this:
+
+        module Copyable
+          def copy_to(destination)
+            Notification.suppress do
+              # Copy logic that creates new comments that we do not want triggering
+              # notifications.
+            end
+          end
+        end
+
+    *Michael Ryan*
+
+*   `:time` option added for `#touch`.
+
+    Fixes #18905.
+
+    *Hyonjee Joo*
+
+*   Deprecate passing of `start` value to `find_in_batches` and `find_each`
+    in favour of `begin_at` value.
+
+    *Vipul A M*
+
+*   Add `foreign_key_exists?` method.
+
+    *Tõnis Simo*
+
+*   Use SQL COUNT and LIMIT 1 queries for `none?` and `one?` methods
+    if no block or limit is given, instead of loading the entire
+    collection into memory. This applies to relations (e.g. `User.all`)
+    as well as associations (e.g. `account.users`)
+
+        # Before:
+
+        users.none?
+        # SELECT "users".* FROM "users"
+
+        users.one?
+        # SELECT "users".* FROM "users"
+
+        # After:
+
+        users.none?
+        # SELECT 1 AS one FROM "users" LIMIT 1
+
+        users.one?
+        # SELECT COUNT(*) FROM "users"
+
+    *Eugene Gilburg*
+
+*   Have `enum` perform type casting consistently with the rest of Active
+    Record, such as `where`.
+
+    *Sean Griffin*
+
+*   `scoping` no longer pollutes the current scope of sibling classes when using
+    STI. e.x.
+
+        StiOne.none.scoping do
+          StiTwo.all
+        end
+
+    Fixes #18806.
+
+    *Sean Griffin*
+
+*   `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*
+
+*   `find_in_batches` now accepts an `:end_at` parameter that complements the `:start`
+     parameter to specify where to stop batch processing.
+
+    *Vipul A M*
+
+*   Fix a rounding problem for PostgreSQL timestamp columns.
+
+    If a timestamp column has a precision specified, it needs to
+    format according to that.
+
+    *Ryuta Kamizono*
+
+*   Respect the database default charset for `schema_migrations` table.
+
+    The charset of `version` column in `schema_migrations` table depends
+    on the database default charset and collation rather than the encoding
+    of the connection.
+
+    *Ryuta Kamizono*
+
+*   Raise `ArgumentError` when passing `nil` or `false` to `Relation#merge`.
+
+    These are not valid values to merge in a relation, so it should warn users
+    early.
+
+    *Rafael Mendonça França*
+
+*   Use `SCHEMA` instead of `DB_STRUCTURE` for specifying a structure file.
+
+    This makes the db:structure tasks consistent with test:load_structure.
+
+    *Dieter Komendera*
+
+*   Respect custom primary keys for associations when calling `Relation#where`
+
+    Fixes #18813.
+
+    *Sean Griffin*
+
+*   Fix 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*
+
+*   Validation errors would be raised for parent records when an association
+    was saved when the parent had `validate: false`. It should not be the
+    responsibility of the model to validate an associated object unless the
+    object was created or modified by the parent.
+
+    This fixes the issue by skipping validations if the parent record is
+    persisted, not changed, and not marked for destruction.
+
+    Fixes #17621.
+
+    *Eileen M. Uchitelle, Aaron Patterson*
+
+*   Fix n+1 query problem when eager loading nil associations (fixes #18312)
+
+    *Sammy Larbi*
+
+*   Change the default error message from `can't be blank` to `must exist` for
+    the presence validator of the `:required` option on `belongs_to`/`has_one`
+    associations.
+
+    *Henrik Nygren*
+
+*   Fixed ActiveRecord::Relation#group method when an argument is an SQL
+    reserved key word:
+
+    Example:
+
+        SplitTest.group(:key).count
+        Property.group(:value).count
+
+    *Bogdan Gusiev*
+
+*   Added the `#or` method on ActiveRecord::Relation, allowing use of the OR
+    operator to combine WHERE or HAVING clauses.
+
+    Example:
+
+        Post.where('id = 1').or(Post.where('id = 2'))
+        # => SELECT * FROM posts WHERE (id = 1) OR (id = 2)
+
+    *Sean Griffin*, *Matthew Draper*, *Gael Muller*, *Olivier El Mekki*
+
+*   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*
+
+*   Add `ActiveRecord::Base#accessed_fields`, which can be used to quickly
+    discover which fields were read from a model when you are looking to only
+    select the data you need from the database.
+
+    *Sean Griffin*
+
+*   Introduce the `:if_exists` option for `drop_table`.
+
+    Example:
+
+        drop_table(:posts, if_exists: true)
+
+    That would execute:
+
+        DROP TABLE IF EXISTS posts
+
+    If the table doesn't exist, `if_exists: false` (the default) raises an
+    exception whereas `if_exists: true` does nothing.
+
+    *Cody Cutrer*, *Stefan Kanev*, *Ryuta Kamizono*
+
+*   Don't run SQL if attribute value is not changed for update_attribute method.
+
+    *Prathamesh Sonpatki*
+
+*   `time` columns can now get affected by `time_zone_aware_attributes`. If you have
+    set `config.time_zone` to a value other than `'UTC'`, they will be treated
+    as in that time zone by default in Rails 5.1. If this is not the desired
+    behavior, you can set
+
+        ActiveRecord::Base.time_zone_aware_types = [:datetime]
+
+    A deprecation warning will be emitted if you have a `:time` column, and have
+    not explicitly opted out.
+
+    Fixes #3145.
+
+    *Sean Griffin*
+
+*   Tests now run after_commit callbacks. You no longer have to declare
+    `uses_transaction ‘test name’` to test the results of an after_commit.
+
+    after_commit callbacks run after committing a transaction whose parent
+    is not `joinable?`: un-nested transactions, transactions within test cases,
+    and transactions in `console --sandbox`.
+
+    *arthurnn*, *Ravil Bayramgalin*, *Matthew Draper*
+
+*   `nil` as a value for a binary column in a query no longer logs as
+    "<NULL binary data>", and instead logs as just "nil".
+
+    *Sean Griffin*
+
+*   `attribute_will_change!` will no longer cause non-persistable attributes to
+    be sent to the database.
+
+    Fixes #18407.
+
+    *Sean Griffin*
+
+*   Remove support for the `protected_attributes` gem.
+
+    *Carlos Antonio da Silva*, *Roberto Miranda*
+
 *   Fix accessing of fixtures having non-string labels like Fixnum.
 
     *Prathamesh Sonpatki*
@@ -10,7 +495,7 @@
 
     *Yves Senn*
 
-*   Remove deprecation when modifying a relation with cached arel.
+*   Remove deprecation when modifying a relation with cached Arel.
     This raises an `ImmutableRelation` error instead.
 
     *Yves Senn*
@@ -100,13 +585,13 @@
 
     *Florian Weingarten*
 
-*   Fixed setting of foreign_key for through associations while building of new record.
+*   Fix setting of foreign_key for through associations when building a new record.
 
     Fixes #12698.
 
     *Ivan Antropov*
 
-*   Improve a dump of the primary key support. If it is not a default primary key,
+*   Improve dumping of the primary key. If it is not a default primary key,
     correctly dump the type and options.
 
     Fixes #14169, #16599.
@@ -124,18 +609,18 @@
 
     *Ryuta Kamizono*
 
-*   Allow precision option for MySQL datetimes.
+*   Allow a precision option for MySQL datetimes.
 
     *Ryuta Kamizono*
 
-*   Fixed automatic inverse_of for models nested in module.
+*   Fixed automatic `inverse_of` for models nested in a module.
 
     *Andrew McCloud*
 
 *   Change `ActiveRecord::Relation#update` behavior so that it can
     be called without passing ids of the records to be updated.
 
-    This change allows to update multiple records returned by
+    This change allows updating multiple records returned by
     `ActiveRecord::Relation` with callbacks and validations.
 
         # Before
@@ -167,6 +652,13 @@
 
     *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
@@ -176,7 +668,7 @@
 
     *arthurnn*
 
-*   `validates_size_of` / `validates_length_of` do not count records,
+*   `validates_size_of` / `validates_length_of` do not count records
     which are `marked_for_destruction?`.
 
     Fixes #7247.
@@ -218,7 +710,7 @@
 
     *Ryuta Kamizono*
 
-*   Support for any type primary key.
+*   Support for any type of primary key.
 
     Fixes #14194.
 
@@ -244,7 +736,7 @@
 
     *Yves Senn*
 
-*   Fixes bug with 'ActiveRecord::Type::Numeric' that causes negative values to
+*   Fix bug with 'ActiveRecord::Type::Numeric' that caused negative values to
     be marked as having changed when set to the same negative value.
 
     Closes #18161.
@@ -274,7 +766,7 @@
 
     This option enables to define the column name of associated object's type for polymorphic associations.
 
-    *Ulisses Almeida, Kassio Borges*
+    *Ulisses Almeida*, *Kassio Borges*
 
 *   Remove deprecated behavior allowing nested arrays to be passed as query
     values.