Bring abstract_controller up to date with rails/master

Resolved all the conflicts since 2.3.0 -> HEAD. Following is a list
of commits that could not be applied cleanly or are obviated with the
abstract_controller refactor. They all need to be revisited to ensure
that fixes made in 2.3 do not reappear in 3.0:

2259ecf368e6a6715966f69216e3ee86bf1a82a7
AR not available
  * This will be reimplemented with ActionORM or equivalent

06182ea02e92afad579998aa80144588e8865ac3
implicitly rendering a js response should not use the default layout
[#1844 state:resolved]
  * This will be handled generically

893e9eb99504705419ad6edac14d00e71cef5f12
Improve view rendering performance in development mode and reinstate
template recompiling in production [#1909 state:resolved]
  * We will need to reimplement rails-dev-boost on top of the refactor;
    the changes here are very implementation specific and cannot be
    cleanly applied. The following commits are implicated:

      199e750d46c04970b5e7684998d09405648ecbd4
      3942cb406e1d5db0ac00e03153809cc8dc4cc4db
      f8ea9f85d4f1e3e6f3b5d895bef6b013aa4b0690
      e3b166aab37ddc2fbab030b146eb61713b91bf55
      ae9f258e03c9fd5088da12c1c6cd216cc89a01f7
      44423126c6f6133a1d9cf1d0832b527e8711d40f

0cb020b4d6d838025859bd60fb8151c8e21b8e84
workaround for picking layouts based on wrong view_paths
[#1974 state:resolved]
  * The specifics of this commit no longer apply. Since it is a two-line
    commit, we will reimplement this change.

8c5cc66a831aadb159f3daaffa4208064c30af0e
make action_controller/layouts pick templates from the current instance's
view_paths instead of the class view_paths [#1974 state:resolved]
  * This does not apply at all. It should be trivial to apply the feature
    to the reimplemented ActionController::Base.

87e8b162463f13bd50d27398f020769460a770e3
fix HTML fallback for explicit templates [#2052 state:resolved]
  * There were a number of patches related to this that simply compounded
    each other. Basically none of them apply cleanly, and the underlying
    issue needs to be revisited. After discussing the underlying problem
    with Koz, we will defer these fixes for further discussion.

1 files changed, 329 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/nested_attributes.rb b/activerecord/lib/active_record/nested_attributes.rb
new file mode 100644
index 0000000000..e3122d195a
--- /dev/null
+++ b/activerecord/lib/active_record/nested_attributes.rb
@@ -0,0 +1,329 @@
+module ActiveRecord
+  module NestedAttributes #:nodoc:
+    def self.included(base)
+      base.extend(ClassMethods)
+      base.class_inheritable_accessor :reject_new_nested_attributes_procs, :instance_writer => false
+      base.reject_new_nested_attributes_procs = {}
+    end
+
+    # == Nested Attributes
+    #
+    # Nested attributes allow you to save attributes on associated records
+    # through the parent. By default nested attribute updating is turned off,
+    # you can enable it using the accepts_nested_attributes_for class method.
+    # When you enable nested attributes an attribute writer is defined on
+    # the model.
+    #
+    # The attribute writer is named after the association, which means that
+    # in the following example, two new methods are added to your model:
+    # <tt>author_attributes=(attributes)</tt> and
+    # <tt>pages_attributes=(attributes)</tt>.
+    #
+    #   class Book < ActiveRecord::Base
+    #     has_one :author
+    #     has_many :pages
+    #
+    #     accepts_nested_attributes_for :author, :pages
+    #   end
+    #
+    # Note that the <tt>:autosave</tt> option is automatically enabled on every
+    # association that accepts_nested_attributes_for is used for.
+    #
+    # === One-to-one
+    #
+    # Consider a Member model that has one Avatar:
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_one :avatar
+    #     accepts_nested_attributes_for :avatar
+    #   end
+    #
+    # Enabling nested attributes on a one-to-one association allows you to
+    # create the member and avatar in one go:
+    #
+    #   params = { :member => { :name => 'Jack', :avatar_attributes => { :icon => 'smiling' } } }
+    #   member = Member.create(params)
+    #   member.avatar.id # => 2
+    #   member.avatar.icon # => 'smiling'
+    #
+    # It also allows you to update the avatar through the member:
+    #
+    #   params = { :member' => { :avatar_attributes => { :id => '2', :icon => 'sad' } } }
+    #   member.update_attributes params['member']
+    #   member.avatar.icon # => 'sad'
+    #
+    # By default you will only be able to set and update attributes on the
+    # associated model. If you want to destroy the associated model through the
+    # attributes hash, you have to enable it first using the
+    # <tt>:allow_destroy</tt> option.
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_one :avatar
+    #     accepts_nested_attributes_for :avatar, :allow_destroy => true
+    #   end
+    #
+    # Now, when you add the <tt>_delete</tt> key to the attributes hash, with a
+    # value that evaluates to +true+, you will destroy the associated model:
+    #
+    #   member.avatar_attributes = { :id => '2', :_delete => '1' }
+    #   member.avatar.marked_for_destruction? # => true
+    #   member.save
+    #   member.avatar #=> nil
+    #
+    # Note that the model will _not_ be destroyed until the parent is saved.
+    #
+    # === One-to-many
+    #
+    # Consider a member that has a number of posts:
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_many :posts
+    #     accepts_nested_attributes_for :posts
+    #   end
+    #
+    # You can now set or update attributes on an associated post model through
+    # the attribute hash.
+    #
+    # For each hash that does _not_ have an <tt>id</tt> key a new record will
+    # be instantiated, unless the hash also contains a <tt>_delete</tt> key
+    # that evaluates to +true+.
+    #
+    #   params = { :member => {
+    #     :name => 'joe', :posts_attributes => [
+    #       { :title => 'Kari, the awesome Ruby documentation browser!' },
+    #       { :title => 'The egalitarian assumption of the modern citizen' },
+    #       { :title => '', :_delete => '1' } # this will be ignored
+    #     ]
+    #   }}
+    #
+    #   member = Member.create(params['member'])
+    #   member.posts.length # => 2
+    #   member.posts.first.title # => 'Kari, the awesome Ruby documentation browser!'
+    #   member.posts.second.title # => 'The egalitarian assumption of the modern citizen'
+    #
+    # You may also set a :reject_if proc to silently ignore any new record
+    # hashes if they fail to pass your criteria. For example, the previous
+    # example could be rewritten as:
+    #
+    #    class Member < ActiveRecord::Base
+    #      has_many :posts
+    #      accepts_nested_attributes_for :posts, :reject_if => proc { |attributes| attributes['title'].blank? }
+    #    end
+    #
+    #   params = { :member => {
+    #     :name => 'joe', :posts_attributes => [
+    #       { :title => 'Kari, the awesome Ruby documentation browser!' },
+    #       { :title => 'The egalitarian assumption of the modern citizen' },
+    #       { :title => '' } # this will be ignored because of the :reject_if proc
+    #     ]
+    #   }}
+    #
+    #   member = Member.create(params['member'])
+    #   member.posts.length # => 2
+    #   member.posts.first.title # => 'Kari, the awesome Ruby documentation browser!'
+    #   member.posts.second.title # => 'The egalitarian assumption of the modern citizen'
+    #
+    # If the hash contains an <tt>id</tt> key that matches an already
+    # associated record, the matching record will be modified:
+    #
+    #   member.attributes = {
+    #     :name => 'Joe',
+    #     :posts_attributes => [
+    #       { :id => 1, :title => '[UPDATED] An, as of yet, undisclosed awesome Ruby documentation browser!' },
+    #       { :id => 2, :title => '[UPDATED] other post' }
+    #     ]
+    #   }
+    #
+    #   member.posts.first.title # => '[UPDATED] An, as of yet, undisclosed awesome Ruby documentation browser!'
+    #   member.posts.second.title # => '[UPDATED] other post'
+    #
+    # By default the associated records are protected from being destroyed. If
+    # you want to destroy any of the associated records through the attributes
+    # hash, you have to enable it first using the <tt>:allow_destroy</tt>
+    # option. This will allow you to also use the <tt>_delete</tt> key to
+    # destroy existing records:
+    #
+    #   class Member < ActiveRecord::Base
+    #     has_many :posts
+    #     accepts_nested_attributes_for :posts, :allow_destroy => true
+    #   end
+    #
+    #   params = { :member => {
+    #     :posts_attributes => [{ :id => '2', :_delete => '1' }]
+    #   }}
+    #
+    #   member.attributes = params['member']
+    #   member.posts.detect { |p| p.id == 2 }.marked_for_destruction? # => true
+    #   member.posts.length #=> 2
+    #   member.save
+    #   member.posts.length # => 1
+    #
+    # === Saving
+    #
+    # All changes to models, including the destruction of those marked for
+    # destruction, are saved and destroyed automatically and atomically when
+    # the parent model is saved. This happens inside the transaction initiated
+    # by the parents save method. See ActiveRecord::AutosaveAssociation.
+    module ClassMethods
+      # Defines an attributes writer for the specified association(s). If you
+      # are using <tt>attr_protected</tt> or <tt>attr_accessible</tt>, then you
+      # will need to add the attribute writer to the allowed list.
+      #
+      # Supported options:
+      # [:allow_destroy]
+      #   If true, destroys any members from the attributes hash with a
+      #   <tt>_delete</tt> key and a value that evaluates to +true+
+      #   (eg. 1, '1', true, or 'true'). This option is off by default.
+      # [:reject_if]
+      #   Allows you to specify a Proc that checks whether a record should be
+      #   built for a certain attribute hash. The hash is passed to the Proc
+      #   and the Proc should return either +true+ or +false+. When no Proc
+      #   is specified a record will be built for all attribute hashes that
+      #   do not have a <tt>_delete</tt> that evaluates to true.
+      #
+      # Examples:
+      #   # creates avatar_attributes=
+      #   accepts_nested_attributes_for :avatar, :reject_if => proc { |attributes| attributes['name'].blank? }
+      #   # creates avatar_attributes= and posts_attributes=
+      #   accepts_nested_attributes_for :avatar, :posts, :allow_destroy => true
+      def accepts_nested_attributes_for(*attr_names)
+        options = { :allow_destroy => false }
+        options.update(attr_names.extract_options!)
+        options.assert_valid_keys(:allow_destroy, :reject_if)
+
+        attr_names.each do |association_name|
+          if reflection = reflect_on_association(association_name)
+            type = case reflection.macro
+            when :has_one, :belongs_to
+              :one_to_one
+            when :has_many, :has_and_belongs_to_many
+              :collection
+            end
+
+            reflection.options[:autosave] = true
+            self.reject_new_nested_attributes_procs[association_name.to_sym] = options[:reject_if]
+
+            # def pirate_attributes=(attributes)
+            #   assign_nested_attributes_for_one_to_one_association(:pirate, attributes, false)
+            # end
+            class_eval %{
+              def #{association_name}_attributes=(attributes)
+                assign_nested_attributes_for_#{type}_association(:#{association_name}, attributes, #{options[:allow_destroy]})
+              end
+            }, __FILE__, __LINE__
+          else
+            raise ArgumentError, "No association found for name `#{association_name}'. Has it been defined yet?"
+          end
+        end
+      end
+    end
+
+    # Returns ActiveRecord::AutosaveAssociation::marked_for_destruction? It's
+    # used in conjunction with fields_for to build a form element for the
+    # destruction of this association.
+    #
+    # See ActionView::Helpers::FormHelper::fields_for for more info.
+    def _delete
+      marked_for_destruction?
+    end
+
+    private
+
+    # Attribute hash keys that should not be assigned as normal attributes.
+    # These hash keys are nested attributes implementation details.
+    UNASSIGNABLE_KEYS = %w{ id _delete }
+
+    # Assigns the given attributes to the association.
+    #
+    # If the given attributes include an <tt>:id</tt> that matches the existing
+    # record’s id, then the existing record will be modified. Otherwise a new
+    # record will be built.
+    #
+    # If the given attributes include a matching <tt>:id</tt> attribute _and_ a
+    # <tt>:_delete</tt> key set to a truthy value, then the existing record
+    # will be marked for destruction.
+    def assign_nested_attributes_for_one_to_one_association(association_name, attributes, allow_destroy)
+      attributes = attributes.stringify_keys
+
+      if attributes['id'].blank?
+        unless reject_new_record?(association_name, attributes)
+          send("build_#{association_name}", attributes.except(*UNASSIGNABLE_KEYS))
+        end
+      elsif (existing_record = send(association_name)) && existing_record.id.to_s == attributes['id'].to_s
+        assign_to_or_mark_for_destruction(existing_record, attributes, allow_destroy)
+      end
+    end
+
+    # Assigns the given attributes to the collection association.
+    #
+    # Hashes with an <tt>:id</tt> value matching an existing associated record
+    # will update that record. Hashes without an <tt>:id</tt> value will build
+    # a new record for the association. Hashes with a matching <tt>:id</tt>
+    # value and a <tt>:_delete</tt> key set to a truthy value will mark the
+    # matched record for destruction.
+    #
+    # For example:
+    #
+    #   assign_nested_attributes_for_collection_association(:people, {
+    #     '1' => { :id => '1', :name => 'Peter' },
+    #     '2' => { :name => 'John' },
+    #     '3' => { :id => '2', :_delete => true }
+    #   })
+    #
+    # Will update the name of the Person with ID 1, build a new associated
+    # person with the name `John', and mark the associatied Person with ID 2
+    # for destruction.
+    #
+    # Also accepts an Array of attribute hashes:
+    #
+    #   assign_nested_attributes_for_collection_association(:people, [
+    #     { :id => '1', :name => 'Peter' },
+    #     { :name => 'John' },
+    #     { :id => '2', :_delete => true }
+    #   ])
+    def assign_nested_attributes_for_collection_association(association_name, attributes_collection, allow_destroy)
+      unless attributes_collection.is_a?(Hash) || attributes_collection.is_a?(Array)
+        raise ArgumentError, "Hash or Array expected, got #{attributes_collection.class.name} (#{attributes_collection.inspect})"
+      end
+
+      if attributes_collection.is_a? Hash
+        attributes_collection = attributes_collection.sort_by { |index, _| index.to_i }.map { |_, attributes| attributes }
+      end
+
+      attributes_collection.each do |attributes|
+        attributes = attributes.stringify_keys
+
+        if attributes['id'].blank?
+          unless reject_new_record?(association_name, attributes)
+            send(association_name).build(attributes.except(*UNASSIGNABLE_KEYS))
+          end
+        elsif existing_record = send(association_name).detect { |record| record.id.to_s == attributes['id'].to_s }
+          assign_to_or_mark_for_destruction(existing_record, attributes, allow_destroy)
+        end
+      end
+    end
+
+    # Updates a record with the +attributes+ or marks it for destruction if
+    # +allow_destroy+ is +true+ and has_delete_flag? returns +true+.
+    def assign_to_or_mark_for_destruction(record, attributes, allow_destroy)
+      if has_delete_flag?(attributes) && allow_destroy
+        record.mark_for_destruction
+      else
+        record.attributes = attributes.except(*UNASSIGNABLE_KEYS)
+      end
+    end
+
+    # Determines if a hash contains a truthy _delete key.
+    def has_delete_flag?(hash)
+      ConnectionAdapters::Column.value_to_boolean hash['_delete']
+    end
+
+    # Determines if a new record should be build by checking for
+    # has_delete_flag? or if a <tt>:reject_if</tt> proc exists for this
+    # association and evaluates to +true+.
+    def reject_new_record?(association_name, attributes)
+      has_delete_flag?(attributes) ||
+        self.class.reject_new_nested_attributes_procs[association_name].try(:call, attributes)
+    end
+  end
+end