Merge branch 'master' of github.com:rails/rails

21 files changed, 201 insertions, 110 deletions

diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index 945f22d3c8..18da28d480 100644
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -447,9 +447,11 @@ module ActiveRecord
     #
     # Possible callbacks are: +before_add+, +after_add+, +before_remove+ and +after_remove+.
     #
-    # Should any of the +before_add+ callbacks throw an exception, the object does not get
-    # added to the collection. Same with the +before_remove+ callbacks; if an exception is
-    # thrown the object doesn't get removed.
+    # If any of the +before_add+ callbacks throw an exception, the object will not be
+    # added to the collection.
+    #
+    # Similarly, if any of the +before_remove+ callbacks throw an exception, the object
+    # will not be removed from the collection.
     #
     # == Association extensions
     #
@@ -647,7 +649,7 @@ module ActiveRecord
     #     belongs_to :commenter
     #   end
     #
-    # When using nested association, you will not be able to modify the association because there
+    # When using a nested association, you will not be able to modify the association because there
     # is not enough information to know what modification to make. For example, if you tried to
     # add a <tt>Commenter</tt> in the example above, there would be no way to tell how to set up the
     # intermediate <tt>Post</tt> and <tt>Comment</tt> objects.
@@ -717,7 +719,7 @@ module ActiveRecord
     # == Eager loading of associations
     #
     # Eager loading is a way to find objects of a certain class and a number of named associations.
-    # This is one of the easiest ways of to prevent the dreaded N+1 problem in which fetching 100
+    # It is one of the easiest ways to prevent the dreaded N+1 problem in which fetching 100
     # posts that each need to display their author triggers 101 database queries. Through the
     # use of eager loading, the number of queries will be reduced from 101 to 2.
     #
@@ -749,16 +751,16 @@ module ActiveRecord
     #   Post.includes(:author, :comments).each do |post|
     #
     # This will load all comments with a single query. This reduces the total number of queries
-    # to 3. More generally the number of queries will be 1 plus the number of associations
+    # to 3. In general, the number of queries will be 1 plus the number of associations
     # named (except if some of the associations are polymorphic +belongs_to+ - see below).
     #
     # To include a deep hierarchy of associations, use a hash:
     #
-    #   Post.includes(:author, {comments: {author: :gravatar}}).each do |post|
+    #   Post.includes(:author, { comments: { author: :gravatar } }).each do |post|
     #
-    # That'll grab not only all the comments but all their authors and gravatar pictures.
-    # You can mix and match symbols, arrays and hashes in any combination to describe the
-    # associations you want to load.
+    # The above code will load all the comments and all of their associated
+    # authors and gravatars. You can mix and match any combination of symbols,
+    # arrays, and hashes to retrieve the associations you want to load.
     #
     # All of this power shouldn't fool you into thinking that you can pull out huge amounts
     # of data with no performance penalty just because you've reduced the number of queries.
@@ -767,8 +769,8 @@ module ActiveRecord
     # cut down on the number of queries in a situation as the one described above.
     #
     # Since only one table is loaded at a time, conditions or orders cannot reference tables
-    # other than the main one. If this is the case Active Record falls back to the previously
-    # used LEFT OUTER JOIN based strategy. For example
+    # other than the main one. If this is the case, Active Record falls back to the previously
+    # used LEFT OUTER JOIN based strategy. For example:
     #
     #   Post.includes([:author, :comments]).where(['comments.approved = ?', true])
     #
@@ -1133,6 +1135,31 @@ module ActiveRecord
       # * <tt>Firm#clients.create!</tt> (similar to <tt>c = Client.new("firm_id" => id); c.save!</tt>)
       # The declaration can also include an +options+ hash to specialize the behavior of the association.
       #
+      # === Scopes
+      #
+      # You can pass a second argument +scope+ as a callable (i.e. proc or
+      # lambda) to retrieve a specific set of records or customize the generated
+      # query when you access the associated collection.
+      #
+      # Scope examples:
+      #   has_many :comments, -> { where(author_id: 1) }
+      #   has_many :employees, -> { joins(:address) }
+      #   has_many :posts, ->(post) { where("max_post_length > ?", post.length) }
+      #
+      # === Extensions
+      #
+      # The +extension+ argument allows you to pass a block into a has_many
+      # association. This is useful for adding new finders, creators and other
+      # factory-type methods to be used as part of the association.
+      #
+      # Extension examples:
+      #   has_many :employees do
+      #     def find_or_create_by_name(name)
+      #       first_name, last_name = name.split(" ", 2)
+      #       find_or_create_by(first_name: first_name, last_name: last_name)
+      #     end
+      #   end
+      #
       # === Options
       # [:class_name]
       #   Specify the class name of the association. Use it only if that name can't be inferred
@@ -1257,6 +1284,17 @@ module ActiveRecord
       # * <tt>Account#create_beneficiary</tt> (similar to <tt>b = Beneficiary.new("account_id" => id); b.save; b</tt>)
       # * <tt>Account#create_beneficiary!</tt> (similar to <tt>b = Beneficiary.new("account_id" => id); b.save!; b</tt>)
       #
+      # === Scopes
+      #
+      # You can pass a second argument +scope+ as a callable (i.e. proc or
+      # lambda) to retrieve a specific record or customize the generated query
+      # when you access the associated object.
+      #
+      # Scope examples:
+      #   has_one :author, -> { where(comment_id: 1) }
+      #   has_one :employer, -> { joins(:company) }
+      #   has_one :dob, ->(dob) { where("Date.new(2000, 01, 01) > ?", dob) }
+      #
       # === Options
       #
       # The declaration can also include an +options+ hash to specialize the behavior of the association.
@@ -1554,6 +1592,33 @@ module ActiveRecord
       # * <tt>Developer#projects.create</tt> (similar to <tt>c = Project.new("developer_id" => id); c.save; c</tt>)
       # The declaration may include an +options+ hash to specialize the behavior of the association.
       #
+      # === Scopes
+      #
+      # You can pass a second argument +scope+ as a callable (i.e. proc or
+      # lambda) to retrieve a specific set of records or customize the generated
+      # query when you access the associated collection.
+      #
+      # Scope examples:
+      #   has_and_belongs_to_many :projects, -> { includes :milestones, :manager }
+      #   has_and_belongs_to_many :categories, ->(category) {
+      #     where("default_category = ?", category.name)
+      #   }
+      #
+      # === Extensions
+      #
+      # The +extension+ argument allows you to pass a block into a
+      # has_and_belongs_to_many association. This is useful for adding new
+      # finders, creators and other factory-type methods to be used as part of
+      # the association.
+      #
+      # Extension examples:
+      #   has_and_belongs_to_many :contractors do
+      #     def find_or_create_by_name(name)
+      #       first_name, last_name = name.split(" ", 2)
+      #       find_or_create_by(first_name: first_name, last_name: last_name)
+      #     end
+      #   end
+      #
       # === Options
       #
       # [:class_name]
diff --git a/activerecord/lib/active_record/associations/collection_proxy.rb b/activerecord/lib/active_record/associations/collection_proxy.rb
index 84c8cfe72b..8c7b0b4be9 100644
--- a/activerecord/lib/active_record/associations/collection_proxy.rb
+++ b/activerecord/lib/active_record/associations/collection_proxy.rb
@@ -783,7 +783,7 @@ module ActiveRecord
       #   person.pets.count # => 0
       #   person.pets.any?  # => true
       #
-      # You can also pass a block to define criteria. The behavior
+      # You can also pass a +block+ to define criteria. The behavior
       # is the same, it returns true if the collection based on the
       # criteria is not empty.
       #
@@ -817,7 +817,7 @@ module ActiveRecord
       #   person.pets.count # => 2
       #   person.pets.many? # => true
       #
-      # You can also pass a block to define criteria. The
+      # You can also pass a +block+ to define criteria. The
       # behavior is the same, it returns true if the collection
       # based on the criteria has more than one record.
       #
@@ -841,7 +841,7 @@ module ActiveRecord
         @association.many?(&block)
       end
 
-      # Returns +true+ if the given object is present in the collection.
+      # Returns +true+ if the given +record+ is present in the collection.
       #
       #   class Person < ActiveRecord::Base
       #     has_many :pets
@@ -879,7 +879,7 @@ module ActiveRecord
 
       # Equivalent to <tt>Array#==</tt>. Returns +true+ if the two arrays
       # contain the same number of elements and if each element is equal
-      # to the corresponding element in the other array, otherwise returns
+      # to the corresponding element in the +other+ array, otherwise returns
       # +false+.
       #
       #   class Person < ActiveRecord::Base
diff --git a/activerecord/lib/active_record/associations/has_many_through_association.rb b/activerecord/lib/active_record/associations/has_many_through_association.rb
index 44c4436e95..0968b0068e 100644
--- a/activerecord/lib/active_record/associations/has_many_through_association.rb
+++ b/activerecord/lib/active_record/associations/has_many_through_association.rb
@@ -63,12 +63,12 @@ module ActiveRecord
 
         save_through_record(record)
         if has_cached_counter? && !through_reflection_updates_counter_cache?
-          ActiveSupport::Deprecation.warn(<<-MESSAGE.strip_heredoc)
-            Automatic updating of counter caches on through associations has been
-            deprecated, and will be removed in Rails 5.0. Instead, please set the
-            appropriate counter_cache options on the has_many and belongs_to for
-            your associations to #{through_reflection.name}.
-          MESSAGE
+          ActiveSupport::Deprecation.warn \
+            "Automatic updating of counter caches on through associations has been " \
+            "deprecated, and will be removed in Rails 5.0. Instead, please set the " \
+            "appropriate counter_cache options on the has_many and belongs_to for " \
+            "your associations to #{through_reflection.name}."
+
           update_counter_in_database(1)
         end
         record
diff --git a/activerecord/lib/active_record/associations/through_association.rb b/activerecord/lib/active_record/associations/through_association.rb
index 611d471e62..e47e81aa0f 100644
--- a/activerecord/lib/active_record/associations/through_association.rb
+++ b/activerecord/lib/active_record/associations/through_association.rb
@@ -15,7 +15,11 @@ module ActiveRecord
           scope = super
           reflection.chain.drop(1).each do |reflection|
             relation = reflection.klass.all
-            relation.merge!(reflection.scope) if reflection.scope
+
+            reflection_scope = reflection.scope
+            if reflection_scope && reflection_scope.arity.zero?
+              relation.merge!(reflection_scope)
+            end
 
             scope.merge!(
               relation.except(:select, :create_with, :includes, :preload, :joins, :eager_load)
diff --git a/activerecord/lib/active_record/attribute_methods.rb b/activerecord/lib/active_record/attribute_methods.rb
index 1ff28ceccc..ceee96b3a8 100644
--- a/activerecord/lib/active_record/attribute_methods.rb
+++ b/activerecord/lib/active_record/attribute_methods.rb
@@ -203,11 +203,9 @@ module ActiveRecord
       def column_for_attribute(name)
         column = columns_hash[name.to_s]
         if column.nil?
-          ActiveSupport::Deprecation.warn(<<-MESSAGE.strip_heredoc)
-            `column_for_attribute` will return a null object for non-existent columns
-            in Rails 5.0. Use `has_attribute?` if you need to check for an
-            attribute's existence.
-          MESSAGE
+          ActiveSupport::Deprecation.warn \
+            "`column_for_attribute` will return a null object for non-existent columns " \
+            "in Rails 5.0. Use `has_attribute?` if you need to check for an attribute's existence."
         end
         column
       end
diff --git a/activerecord/lib/active_record/attribute_methods/dirty.rb b/activerecord/lib/active_record/attribute_methods/dirty.rb
index d3f4e51c33..2f02738f6d 100644
--- a/activerecord/lib/active_record/attribute_methods/dirty.rb
+++ b/activerecord/lib/active_record/attribute_methods/dirty.rb
@@ -43,14 +43,6 @@ module ActiveRecord
         calculate_changes_from_defaults
       end
 
-      def changed?
-        super || changed_in_place.any?
-      end
-
-      def changed
-        super | changed_in_place
-      end
-
       def changes_applied
         super
         store_original_raw_attributes
@@ -62,7 +54,19 @@ module ActiveRecord
       end
 
       def changed_attributes
-        super.reverse_merge(attributes_changed_in_place).freeze
+        # This should only be set by methods which will call changed_attributes
+        # multiple times when it is known that the computed value cannot change.
+        if defined?(@cached_changed_attributes)
+          @cached_changed_attributes
+        else
+          super.reverse_merge(attributes_changed_in_place).freeze
+        end
+      end
+
+      def changes
+        cache_changed_attributes do
+          super
+        end
       end
 
       private
@@ -165,6 +169,13 @@ module ActiveRecord
           store_original_raw_attribute(attr)
         end
       end
+
+      def cache_changed_attributes
+        @cached_changed_attributes = changed_attributes
+        yield
+      ensure
+        remove_instance_variable(:@cached_changed_attributes)
+      end
     end
   end
 end
diff --git a/activerecord/lib/active_record/attribute_methods/read.rb b/activerecord/lib/active_record/attribute_methods/read.rb
index 10869dfc1e..bf2a084a00 100644
--- a/activerecord/lib/active_record/attribute_methods/read.rb
+++ b/activerecord/lib/active_record/attribute_methods/read.rb
@@ -46,9 +46,7 @@ module ActiveRecord
         protected
 
         def cached_attributes_deprecation_warning(method_name)
-          ActiveSupport::Deprecation.warn(<<-MESSAGE.strip_heredoc)
-            Calling `#{method_name}` is no longer necessary. All attributes are cached.
-          MESSAGE
+          ActiveSupport::Deprecation.warn "Calling `#{method_name}` is no longer necessary. All attributes are cached."
         end
 
         if Module.methods_transplantable?
diff --git a/activerecord/lib/active_record/attribute_methods/serialization.rb b/activerecord/lib/active_record/attribute_methods/serialization.rb
index 264ce2bdfa..100d6d4229 100644
--- a/activerecord/lib/active_record/attribute_methods/serialization.rb
+++ b/activerecord/lib/active_record/attribute_methods/serialization.rb
@@ -54,10 +54,9 @@ module ActiveRecord
         end
 
         def serialized_attributes
-          ActiveSupport::Deprecation.warn(<<-WARNING.strip_heredoc)
-            `serialized_attributes` is deprecated without replacement, and will
-            be removed in Rails 5.0.
-          WARNING
+          ActiveSupport::Deprecation.warn "`serialized_attributes` is deprecated " \
+            "without replacement, and will be removed in Rails 5.0."
+
           @serialized_attributes ||= Hash[
             columns.select { |t| t.cast_type.is_a?(Type::Serialized) }.map { |c|
               [c.name, c.cast_type.coder]
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
index 92ac607a3c..cf0e3a260d 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -61,12 +61,11 @@ module ActiveRecord
       def emit_warning_if_null_unspecified(options)
         return if options.key?(:null)
 
-        ActiveSupport::Deprecation.warn(<<-MESSAGE.strip_heredoc)
-        `timestamp` was called without specifying an option for `null`. In Rails
-        5.0, this behavior will change to `null: false`. You should manually
-        specify `null: true` to prevent the behavior of your existing migrations
-        from changing.
-        MESSAGE
+        ActiveSupport::Deprecation.warn \
+          "`timestamp` was called without specifying an option for `null`. In Rails " \
+          "5.0, this behavior will change to `null: false`. You should manually " \
+          "specify `null: true` to prevent the behavior of your existing migrations " \
+          "from changing."
       end
     end
 
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb
index ae967d5167..84b9490ba3 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb
@@ -25,10 +25,10 @@ module ActiveRecord
             if !infinity?(from) && extracted[:exclude_start]
               if from.respond_to?(:succ)
                 from = from.succ
-                ActiveSupport::Deprecation.warn <<-MESSAGE
-Excluding the beginning of a Range is only partialy supported through `#succ`.
-This is not reliable and will be removed in the future.
-                MESSAGE
+                ActiveSupport::Deprecation.warn \
+                  "Excluding the beginning of a Range is only partialy supported " \
+                  "through `#succ`. This is not reliable and will be removed in " \
+                  "the future."
               else
                 raise ArgumentError, "The Ruby Range object does not support excluding the beginning of a Range. (unsupported value: '#{value}')"
               end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/uuid.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/uuid.rb
index dd97393eac..033e0324bb 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/uuid.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/uuid.rb
@@ -12,6 +12,8 @@ module ActiveRecord
                              [a-fA-F0-9]{4}-?
                              [a-fA-F0-9]{4}-?\}?\z}x
 
+          alias_method :type_cast_for_database, :type_cast_from_database
+
           def type
             :uuid
           end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
index 7042817672..767b6b614a 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -281,9 +281,9 @@ module ActiveRecord
         def default_sequence_name(table_name, pk = nil) #:nodoc:
           result = serial_sequence(table_name, pk || 'id')
           return nil unless result
-          Utils.extract_schema_qualified_name(result)
+          Utils.extract_schema_qualified_name(result).to_s
         rescue ActiveRecord::StatementInvalid
-          PostgreSQL::Name.new(nil, "#{table_name}_#{pk || 'id'}_seq")
+          PostgreSQL::Name.new(nil, "#{table_name}_#{pk || 'id'}_seq").to_s
         end
 
         def serial_sequence(table, column)
@@ -549,7 +549,8 @@ module ActiveRecord
               # Convert Arel node to string
               s = s.to_sql unless s.is_a?(String)
               # Remove any ASC/DESC modifiers
-              s.gsub(/\s+(?:ASC|DESC)?\s*(?:NULLS\s+(?:FIRST|LAST)\s*)?/i, '')
+              s.gsub(/\s+(?:ASC|DESC)\b/i, '')
+               .gsub(/\s+NULLS\s+(?:FIRST|LAST)\b/i, '')
             }.reject(&:blank?).map.with_index { |column, i| "#{column} AS alias_#{i}" }
 
           [super, *order_columns].join(', ')
diff --git a/activerecord/lib/active_record/core.rb b/activerecord/lib/active_record/core.rb
index d22806fbdf..82b9c79533 100644
--- a/activerecord/lib/active_record/core.rb
+++ b/activerecord/lib/active_record/core.rb
@@ -151,7 +151,7 @@ module ActiveRecord
       end
 
       def find_by(*args)
-        return super if current_scope || args.length > 1 || reflect_on_all_aggregations.any?
+        return super if current_scope || !(Hash === args.first) || reflect_on_all_aggregations.any?
 
         hash = args.first
 
@@ -177,6 +177,10 @@ module ActiveRecord
         end
       end
 
+      def find_by!(*args)
+        find_by(*args) or raise RecordNotFound
+      end
+
       def initialize_generated_modules
         super
 
diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
index 4306b36ae1..a85ba6b539 100644
--- a/activerecord/lib/active_record/fixtures.rb
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -126,7 +126,7 @@ module ActiveRecord
   # that is included in <tt>ActiveRecord::FixtureSet.context_class</tt>.
   #
   # - define a helper method in `test_helper.rb`
-  #     class FixtureFileHelpers
+  #     module FixtureFileHelpers
   #       def file_sha(path)
   #         Digest::SHA2.hexdigest(File.read(Rails.root.join('test/fixtures', path)))
   #       end
@@ -870,11 +870,11 @@ module ActiveRecord
       def try_to_load_dependency(file_name)
         require_dependency file_name
       rescue LoadError => e
-        # Let's hope the developer has included it
-        # Let's warn in case this is a subdependency, otherwise
-        # subdependency error messages are totally cryptic
-        if ActiveRecord::Base.logger
-          ActiveRecord::Base.logger.warn("Unable to load #{file_name}, underlying cause #{e.message} \n\n #{e.backtrace.join("\n")}")
+        unless fixture_class_names.key?(file_name.pluralize)
+          if ActiveRecord::Base.logger
+            ActiveRecord::Base.logger.warn("Unable to load #{file_name}, make sure you added it to ActiveSupport::TestCase.set_fixture_class")
+            ActiveRecord::Base.logger.warn("underlying cause #{e.message} \n\n #{e.backtrace.join("\n")}")
+          end
         end
       end
 
diff --git a/activerecord/lib/active_record/migration.rb b/activerecord/lib/active_record/migration.rb
index 659c5e3bbb..d0d9304a36 100644
--- a/activerecord/lib/active_record/migration.rb
+++ b/activerecord/lib/active_record/migration.rb
@@ -161,21 +161,14 @@ module ActiveRecord
   # in the <tt>db/migrate/</tt> directory where <tt>timestamp</tt> is the
   # UTC formatted date and time that the migration was generated.
   #
-  # You may then edit the <tt>up</tt> and <tt>down</tt> methods of
-  # MyNewMigration.
-  #
   # There is a special syntactic shortcut to generate migrations that add fields to a table.
   #
   #   rails generate migration add_fieldname_to_tablename fieldname:string
   #
   # This will generate the file <tt>timestamp_add_fieldname_to_tablename</tt>, which will look like this:
   #   class AddFieldnameToTablename < ActiveRecord::Migration
-  #     def up
-  #       add_column :tablenames, :fieldname, :string
-  #     end
-  #
-  #     def down
-  #       remove_column :tablenames, :fieldname
+  #     def change
+  #       add_column :tablenames, :field, :string
   #     end
   #   end
   #
@@ -188,9 +181,12 @@ module ActiveRecord
   #
   # To roll the database back to a previous migration version, use
   # <tt>rake db:migrate VERSION=X</tt> where <tt>X</tt> is the version to which
-  # you wish to downgrade. If any of the migrations throw an
-  # <tt>ActiveRecord::IrreversibleMigration</tt> exception, that step will fail and you'll
-  # have some manual work to do.
+  # you wish to downgrade. Alternatively, you can also use the STEP option if you
+  # wish to rollback last few migrations. <tt>rake db:migrate STEP=2</tt> will rollback
+  # the latest two migrations.
+  # 
+  # If any of the migrations throw an <tt>ActiveRecord::IrreversibleMigration</tt> exception, 
+  # that step will fail and you'll have some manual work to do.
   #
   # == Database support
   #
diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index 1547c8e3f4..c0deb76a33 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -38,7 +38,7 @@ module ActiveRecord
       ar.aggregate_reflections = ar.aggregate_reflections.merge(name.to_s => reflection)
     end
 
-    # \Reflection enables interrogating Active Record classes and objects
+    # \Reflection enables interrogating of Active Record classes and objects
     # about their associations and aggregations. This information can,
     # for example, be used in a form builder that takes an Active Record object
     # and creates input fields for all of the attributes depending on their type
@@ -339,12 +339,13 @@ module ActiveRecord
         return unless scope
 
         if scope.arity > 0
-          ActiveSupport::Deprecation.warn <<-WARNING
-The association scope '#{name}' is instance dependent (the scope block takes an argument).
-Preloading happens before the individual instances are created. This means that there is no instance
-being passed to the association scope. This will most likely result in broken or incorrect behavior.
-Joining, Preloading and eager loading of these associations is deprecated and will be removed in the future.
-          WARNING
+          ActiveSupport::Deprecation.warn \
+            "The association scope '#{name}' is instance dependent (the scope " \
+            "block takes an argument). Preloading happens before the individual " \
+            "instances are created. This means that there is no instance being " \
+            "passed to the association scope. This will most likely result in " \
+            "broken or incorrect behavior. Joining, Preloading and eager loading " \
+            "of these associations is deprecated and will be removed in the future."
         end
       end
       alias :check_eager_loadable! :check_preloadable!
@@ -787,15 +788,13 @@ Joining, Preloading and eager loading of these associations is deprecated and wi
         if names.length > 1
           example_options = options.dup
           example_options[:source] = source_reflection_names.first
-          ActiveSupport::Deprecation.warn <<-eowarn
-Ambiguous source reflection for through association.  Please specify a :source
-directive on your declaration like:
-
-  class #{active_record.name} < ActiveRecord::Base
-    #{macro} :#{name}, #{example_options}
-  end
-
-          eowarn
+          ActiveSupport::Deprecation.warn \
+            "Ambiguous source reflection for through association.  Please " \
+            "specify a :source directive on your declaration like:\n" \
+            "\n" \
+            "  class #{active_record.name} < ActiveRecord::Base\n" \
+            "    #{macro} :#{name}, #{example_options}\n" \
+            "  end"
         end
 
         @source_reflection_name = names.first
diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
index 067966321d..e59cce6934 100644
--- a/activerecord/lib/active_record/relation/query_methods.rb
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -94,10 +94,8 @@ module ActiveRecord
     def check_cached_relation # :nodoc:
       if defined?(@arel) && @arel
         @arel = nil
-        ActiveSupport::Deprecation.warn <<-WARNING
-Modifying already cached Relation. The cache will be reset.
-Use a cloned Relation to prevent this warning.
-WARNING
+        ActiveSupport::Deprecation.warn "Modifying already cached Relation. The " \
+          "cache will be reset. Use a cloned Relation to prevent this warning."
       end
     end
 
diff --git a/activerecord/lib/active_record/tasks/database_tasks.rb b/activerecord/lib/active_record/tasks/database_tasks.rb
index 892c78e479..a21c3f1868 100644
--- a/activerecord/lib/active_record/tasks/database_tasks.rb
+++ b/activerecord/lib/active_record/tasks/database_tasks.rb
@@ -131,10 +131,12 @@ module ActiveRecord
         verbose = ENV["VERBOSE"] ? ENV["VERBOSE"] == "true" : true
         version = ENV["VERSION"] ? ENV["VERSION"].to_i : nil
         scope   = ENV['SCOPE']
-        Migration.verbose = verbose
+        verbose_was = Migration.verbose
         Migrator.migrate(Migrator.migrations_paths, version) do |migration|
           scope.blank? || scope == migration.scope
         end
+      ensure
+        Migration.verbose = verbose_was
       end
 
       def charset_current(environment = env)
@@ -184,10 +186,10 @@ module ActiveRecord
       end
 
       def load_schema(format = ActiveRecord::Base.schema_format, file = nil)
-        ActiveSupport::Deprecation.warn(<<-MESSAGE.strip_heredoc)
-          This method will act on a specific connection in the future.
-          To act on the current connection, use `load_schema_current` instead.
-        MESSAGE
+        ActiveSupport::Deprecation.warn \
+          "This method will act on a specific connection in the future. " \
+          "To act on the current connection, use `load_schema_current` instead."
+
         load_schema_current(format, file)
       end
 
diff --git a/activerecord/lib/active_record/transactions.rb b/activerecord/lib/active_record/transactions.rb
index 1bb7aab8fb..45bc10b9b0 100644
--- a/activerecord/lib/active_record/transactions.rb
+++ b/activerecord/lib/active_record/transactions.rb
@@ -3,15 +3,15 @@ module ActiveRecord
   module Transactions
     extend ActiveSupport::Concern
     ACTIONS = [:create, :destroy, :update]
-    CALLBACK_WARN_MESSAGE = <<-EOF
-Currently, Active Record will rescue any errors raised within
-after_rollback/after_commit callbacks and print them to the logs. In the next
-version, these errors will no longer be rescued. Instead, they will simply
-bubble just like other Active Record callbacks.
-
-You can opt into the new behavior and remove this warning by setting
-config.active_record.raise_in_transactional_callbacks to true.
-EOF
+    CALLBACK_WARN_MESSAGE = "Currently, Active Record suppresses errors raised " \
+      "within `after_rollback`/`after_commit` callbacks and only print them to " \
+      "the logs. In the next version, these errors will no longer be suppressed. " \
+      "Instead, the errors will propagate normally just like in other Active " \
+      "Record callbacks.\n" \
+      "\n" \
+      "You can opt into the new behavior and remove this warning by setting:\n" \
+      "\n" \
+      "  config.active_record.raise_in_transactional_callbacks = true"
 
     included do
       define_callbacks :commit, :rollback,
diff --git a/activerecord/lib/active_record/type/binary.rb b/activerecord/lib/active_record/type/binary.rb
index d29ff4e494..005a48ef0d 100644
--- a/activerecord/lib/active_record/type/binary.rb
+++ b/activerecord/lib/active_record/type/binary.rb
@@ -22,6 +22,11 @@ module ActiveRecord
         Data.new(super)
       end
 
+      def changed_in_place?(raw_old_value, value)
+        old_value = type_cast_from_database(raw_old_value)
+        old_value != value
+      end
+
       class Data # :nodoc:
         def initialize(value)
           @value = value.to_s
@@ -30,10 +35,15 @@ module ActiveRecord
         def to_s
           @value
         end
+        alias_method :to_str, :to_s
 
         def hex
           @value.unpack('H*')[0]
         end
+
+        def ==(other)
+          other == to_s || super
+        end
       end
     end
   end
diff --git a/activerecord/lib/active_record/type/serialized.rb b/activerecord/lib/active_record/type/serialized.rb
index abeea769c4..5b512433b0 100644
--- a/activerecord/lib/active_record/type/serialized.rb
+++ b/activerecord/lib/active_record/type/serialized.rb
@@ -26,6 +26,11 @@ module ActiveRecord
         end
       end
 
+      def changed_in_place?(raw_old_value, value)
+        return false if value.nil?
+        subtype.changed_in_place?(raw_old_value, coder.dump(value))
+      end
+
       def accessor
         ActiveRecord::Store::IndifferentHashAccessor
       end