Support establishing connection on ActiveRecord::Model.

This is the 'top level' connection, inherited by any models that include
ActiveRecord::Model or inherit from ActiveRecord::Base.

activerecord/lib/active_record.rb

@@ -59,6 +59,7 @@ module ActiveRecord
     autoload :Callbacks
     autoload :Core
     autoload :CounterCache
+    autoload :ConnectionHandling
     autoload :DynamicMatchers
     autoload :DynamicFinderMatch
     autoload :DynamicScopeMatch

activerecord/lib/active_record/attribute_methods.rb

@@ -61,7 +61,7 @@ module ActiveRecord
           raise DangerousAttributeError, "#{method_name} is defined by ActiveRecord"
         end
 
-        if active_record_super == Base
+        if [Base, Model].include?(active_record_super)
           super
         else
           # If B < A and A defines its own attribute method, then we don't want to overwrite that.

activerecord/lib/active_record/base.rb

@@ -331,5 +331,4 @@ module ActiveRecord #:nodoc:
   end
 end
 
-require 'active_record/connection_adapters/abstract/connection_specification'
 ActiveSupport.run_load_hooks(:active_record, ActiveRecord::Model::DeprecationProxy)

activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb

@@ -370,7 +370,7 @@ connection.  For example: ActiveRecord::Base.connection.close
       def retrieve_connection_pool(klass)
         pool = @class_to_pool[klass.name]
         return pool if pool
-        return nil if ActiveRecord::Base == klass
+        return nil if ActiveRecord::Model == klass
         retrieve_connection_pool klass.active_record_super
       end
     end

activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb

@@ -1,184 +0,0 @@
-require 'active_support/core_ext/module/delegation'
-
-module ActiveRecord
-  module Core
-    class ConnectionSpecification #:nodoc:
-      attr_reader :config, :adapter_method
-      def initialize (config, adapter_method)
-        @config, @adapter_method = config, adapter_method
-      end
-
-      ##
-      # Builds a ConnectionSpecification from user input
-      class Resolver # :nodoc:
-        attr_reader :config, :klass, :configurations
-
-        def initialize(config, configurations)
-          @config         = config
-          @configurations = configurations
-        end
-
-        def spec
-          case config
-          when nil
-            raise AdapterNotSpecified unless defined?(Rails.env)
-            resolve_string_connection Rails.env
-          when Symbol, String
-            resolve_string_connection config.to_s
-          when Hash
-            resolve_hash_connection config
-          end
-        end
-
-        private
-        def resolve_string_connection(spec) # :nodoc:
-          hash = configurations.fetch(spec) do |k|
-            connection_url_to_hash(k)
-          end
-
-          raise(AdapterNotSpecified, "#{spec} database is not configured") unless hash
-
-          resolve_hash_connection hash
-        end
-
-        def resolve_hash_connection(spec) # :nodoc:
-          spec = spec.symbolize_keys
-
-          raise(AdapterNotSpecified, "database configuration does not specify adapter") unless spec.key?(:adapter)
-
-          begin
-            require "active_record/connection_adapters/#{spec[:adapter]}_adapter"
-          rescue LoadError => e
-            raise LoadError, "Please install the #{spec[:adapter]} adapter: `gem install activerecord-#{spec[:adapter]}-adapter` (#{e.message})", e.backtrace
-          end
-
-          adapter_method = "#{spec[:adapter]}_connection"
-
-          ConnectionSpecification.new(spec, adapter_method)
-        end
-
-        def connection_url_to_hash(url) # :nodoc:
-          config = URI.parse url
-          adapter = config.scheme
-          adapter = "postgresql" if adapter == "postgres"
-          spec = { :adapter  => adapter,
-                   :username => config.user,
-                   :password => config.password,
-                   :port     => config.port,
-                   :database => config.path.sub(%r{^/},""),
-                   :host     => config.host }
-          spec.reject!{ |_,value| !value }
-          if config.query
-            options = Hash[config.query.split("&").map{ |pair| pair.split("=") }].symbolize_keys
-            spec.merge!(options)
-          end
-          spec
-        end
-      end
-    end
-
-    # Returns the connection currently associated with the class. This can
-    # also be used to "borrow" the connection to do database work that isn't
-    # easily done without going straight to SQL.
-    def connection
-      self.class.connection
-    end
-
-    module ClassMethods
-      # Establishes the connection to the database. Accepts a hash as input where
-      # the <tt>:adapter</tt> key must be specified with the name of a database adapter (in lower-case)
-      # example for regular databases (MySQL, Postgresql, etc):
-      #
-      #   ActiveRecord::Base.establish_connection(
-      #     :adapter  => "mysql",
-      #     :host     => "localhost",
-      #     :username => "myuser",
-      #     :password => "mypass",
-      #     :database => "somedatabase"
-      #   )
-      #
-      # Example for SQLite database:
-      #
-      #   ActiveRecord::Base.establish_connection(
-      #     :adapter => "sqlite",
-      #     :database  => "path/to/dbfile"
-      #   )
-      #
-      # Also accepts keys as strings (for parsing from YAML for example):
-      #
-      #   ActiveRecord::Base.establish_connection(
-      #     "adapter" => "sqlite",
-      #     "database"  => "path/to/dbfile"
-      #   )
-      #
-      # Or a URL:
-      #
-      #   ActiveRecord::Base.establish_connection(
-      #     "postgres://myuser:mypass@localhost/somedatabase"
-      #   )
-      #
-      # The exceptions AdapterNotSpecified, AdapterNotFound and ArgumentError
-      # may be returned on an error.
-      def establish_connection(spec = ENV["DATABASE_URL"])
-        resolver = ConnectionSpecification::Resolver.new spec, configurations
-        spec = resolver.spec
-
-        unless respond_to?(spec.adapter_method)
-          raise AdapterNotFound, "database configuration specifies nonexistent #{spec.config[:adapter]} adapter"
-        end
-
-        remove_connection
-        connection_handler.establish_connection name, spec
-      end
-
-      # Returns the connection currently associated with the class. This can
-      # also be used to "borrow" the connection to do database work unrelated
-      # to any of the specific Active Records.
-      def connection
-        retrieve_connection
-      end
-
-      def connection_id
-        Thread.current['ActiveRecord::Base.connection_id']
-      end
-
-      def connection_id=(connection_id)
-        Thread.current['ActiveRecord::Base.connection_id'] = connection_id
-      end
-
-      # Returns the configuration of the associated connection as a hash:
-      #
-      #  ActiveRecord::Base.connection_config
-      #  # => {:pool=>5, :timeout=>5000, :database=>"db/development.sqlite3", :adapter=>"sqlite3"}
-      #
-      # Please use only for reading.
-      def connection_config
-        connection_pool.spec.config
-      end
-
-      def connection_pool
-        connection_handler.retrieve_connection_pool(self) or raise ConnectionNotEstablished
-      end
-
-      def retrieve_connection
-        connection_handler.retrieve_connection(self)
-      end
-
-      # Returns true if Active Record is connected.
-      def connected?
-        connection_handler.connected?(self)
-      end
-
-      def remove_connection(klass = self)
-        connection_handler.remove_connection(klass)
-      end
-
-      def clear_active_connections!
-        connection_handler.clear_active_connections!
-      end
-
-      delegate :clear_reloadable_connections!,
-        :clear_all_connections!,:verify_active_connections!, :to => :connection_handler
-    end
-  end
-end

activerecord/lib/active_record/connection_adapters/abstract_adapter.rb

@@ -11,6 +11,7 @@ module ActiveRecord
     extend ActiveSupport::Autoload
 
     autoload :Column
+    autoload :ConnectionSpecification
 
     autoload_under 'abstract' do
       autoload :IndexDefinition,  'active_record/connection_adapters/abstract/schema_definitions'
@@ -26,7 +27,6 @@ module ActiveRecord
       autoload :ConnectionPool
       autoload :ConnectionHandler,       'active_record/connection_adapters/abstract/connection_pool'
       autoload :ConnectionManagement,    'active_record/connection_adapters/abstract/connection_pool'
-      autoload :ConnectionSpecification
 
       autoload :QueryCache
     end

activerecord/lib/active_record/connection_adapters/connection_specification.rb

@@ -0,0 +1,79 @@
+module ActiveRecord
+  module ConnectionAdapters
+    class ConnectionSpecification #:nodoc:
+      attr_reader :config, :adapter_method
+
+      def initialize (config, adapter_method)
+        @config, @adapter_method = config, adapter_method
+      end
+
+      ##
+      # Builds a ConnectionSpecification from user input
+      class Resolver # :nodoc:
+        attr_reader :config, :klass, :configurations
+
+        def initialize(config, configurations)
+          @config         = config
+          @configurations = configurations
+        end
+
+        def spec
+          case config
+          when nil
+            raise AdapterNotSpecified unless defined?(Rails.env)
+            resolve_string_connection Rails.env
+          when Symbol, String
+            resolve_string_connection config.to_s
+          when Hash
+            resolve_hash_connection config
+          end
+        end
+
+        private
+        def resolve_string_connection(spec) # :nodoc:
+          hash = configurations.fetch(spec) do |k|
+            connection_url_to_hash(k)
+          end
+
+          raise(AdapterNotSpecified, "#{spec} database is not configured") unless hash
+
+          resolve_hash_connection hash
+        end
+
+        def resolve_hash_connection(spec) # :nodoc:
+          spec = spec.symbolize_keys
+
+          raise(AdapterNotSpecified, "database configuration does not specify adapter") unless spec.key?(:adapter)
+
+          begin
+            require "active_record/connection_adapters/#{spec[:adapter]}_adapter"
+          rescue LoadError => e
+            raise LoadError, "Please install the #{spec[:adapter]} adapter: `gem install activerecord-#{spec[:adapter]}-adapter` (#{e.message})", e.backtrace
+          end
+
+          adapter_method = "#{spec[:adapter]}_connection"
+
+          ConnectionSpecification.new(spec, adapter_method)
+        end
+
+        def connection_url_to_hash(url) # :nodoc:
+          config = URI.parse url
+          adapter = config.scheme
+          adapter = "postgresql" if adapter == "postgres"
+          spec = { :adapter  => adapter,
+                   :username => config.user,
+                   :password => config.password,
+                   :port     => config.port,
+                   :database => config.path.sub(%r{^/},""),
+                   :host     => config.host }
+          spec.reject!{ |_,value| !value }
+          if config.query
+            options = Hash[config.query.split("&").map{ |pair| pair.split("=") }].symbolize_keys
+            spec.merge!(options)
+          end
+          spec
+        end
+      end
+    end
+  end
+end

activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb

@@ -4,7 +4,7 @@ gem 'mysql2', '~> 0.3.10'
 require 'mysql2'
 
 module ActiveRecord
-  module Core::ClassMethods
+  module ConnectionHandling
     # Establishes a connection to the database that's used by all Active Record objects.
     def mysql2_connection(config)
       config[:username] = 'root' if config[:username].nil?

activerecord/lib/active_record/connection_adapters/mysql_adapter.rb

@@ -18,7 +18,7 @@ class Mysql
 end
 
 module ActiveRecord
-  module Core::ClassMethods
+  module ConnectionHandling
     # Establishes a connection to the database that's used by all Active Record objects.
     def mysql_connection(config) # :nodoc:
       config = config.symbolize_keys

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -7,7 +7,7 @@ gem 'pg', '~> 0.11'
 require 'pg'
 
 module ActiveRecord
-  module Core::ClassMethods
+  module ConnectionHandling
     # Establishes a connection to the database that's used by all Active Record objects
     def postgresql_connection(config) # :nodoc:
       config = config.symbolize_keys

activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb

@@ -4,7 +4,7 @@ gem 'sqlite3', '~> 1.3.5'
 require 'sqlite3'
 
 module ActiveRecord
-  module Core::ClassMethods
+  module ConnectionHandling
     # sqlite3 adapter reuses sqlite_connection.
     def sqlite3_connection(config) # :nodoc:
       # Require database.

activerecord/lib/active_record/connection_handling.rb

@@ -0,0 +1,100 @@
+require 'active_support/core_ext/module/delegation'
+
+module ActiveRecord
+  module ConnectionHandling
+    # Establishes the connection to the database. Accepts a hash as input where
+    # the <tt>:adapter</tt> key must be specified with the name of a database adapter (in lower-case)
+    # example for regular databases (MySQL, Postgresql, etc):
+    #
+    #   ActiveRecord::Base.establish_connection(
+    #     :adapter  => "mysql",
+    #     :host     => "localhost",
+    #     :username => "myuser",
+    #     :password => "mypass",
+    #     :database => "somedatabase"
+    #   )
+    #
+    # Example for SQLite database:
+    #
+    #   ActiveRecord::Base.establish_connection(
+    #     :adapter => "sqlite",
+    #     :database  => "path/to/dbfile"
+    #   )
+    #
+    # Also accepts keys as strings (for parsing from YAML for example):
+    #
+    #   ActiveRecord::Base.establish_connection(
+    #     "adapter" => "sqlite",
+    #     "database"  => "path/to/dbfile"
+    #   )
+    #
+    # Or a URL:
+    #
+    #   ActiveRecord::Base.establish_connection(
+    #     "postgres://myuser:mypass@localhost/somedatabase"
+    #   )
+    #
+    # The exceptions AdapterNotSpecified, AdapterNotFound and ArgumentError
+    # may be returned on an error.
+    def establish_connection(spec = ENV["DATABASE_URL"])
+      resolver = ConnectionAdapters::ConnectionSpecification::Resolver.new spec, configurations
+      spec = resolver.spec
+
+      unless respond_to?(spec.adapter_method)
+        raise AdapterNotFound, "database configuration specifies nonexistent #{spec.config[:adapter]} adapter"
+      end
+
+      remove_connection
+      connection_handler.establish_connection name, spec
+    end
+
+    # Returns the connection currently associated with the class. This can
+    # also be used to "borrow" the connection to do database work unrelated
+    # to any of the specific Active Records.
+    def connection
+      retrieve_connection
+    end
+
+    def connection_id
+      Thread.current['ActiveRecord::Base.connection_id']
+    end
+
+    def connection_id=(connection_id)
+      Thread.current['ActiveRecord::Base.connection_id'] = connection_id
+    end
+
+    # Returns the configuration of the associated connection as a hash:
+    #
+    #  ActiveRecord::Base.connection_config
+    #  # => {:pool=>5, :timeout=>5000, :database=>"db/development.sqlite3", :adapter=>"sqlite3"}
+    #
+    # Please use only for reading.
+    def connection_config
+      connection_pool.spec.config
+    end
+
+    def connection_pool
+      connection_handler.retrieve_connection_pool(self) or raise ConnectionNotEstablished
+    end
+
+    def retrieve_connection
+      connection_handler.retrieve_connection(self)
+    end
+
+    # Returns true if Active Record is connected.
+    def connected?
+      connection_handler.connected?(self)
+    end
+
+    def remove_connection(klass = self)
+      connection_handler.remove_connection(klass)
+    end
+
+    def clear_active_connections!
+      connection_handler.clear_active_connections!
+    end
+
+    delegate :clear_reloadable_connections!,
+      :clear_all_connections!,:verify_active_connections!, :to => :connection_handler
+  end
+end

activerecord/lib/active_record/core.rb

@@ -119,13 +119,7 @@ module ActiveRecord
       end
 
       def arel_engine
-        @arel_engine ||= begin
+        @arel_engine ||= connection_handler.connection_pools[name] ? self : active_record_super.arel_engine
-          if self == ActiveRecord::Base
-            ActiveRecord::Base
-          else
-            connection_handler.connection_pools[name] ? self : active_record_super.arel_engine
-          end
-        end
       end
 
       private
@@ -304,6 +298,13 @@ module ActiveRecord
       @readonly = true
     end
 
+    # Returns the connection currently associated with the class. This can
+    # also be used to "borrow" the connection to do database work that isn't
+    # easily done without going straight to SQL.
+    def connection
+      self.class.connection
+    end
+
     # Returns the contents of the record as a nicely formatted string.
     def inspect
       inspection = if @attributes

activerecord/lib/active_record/inheritance.rb

@@ -17,8 +17,10 @@ module ActiveRecord
 
         if sup.abstract_class?
           sup.descends_from_active_record?
+        elsif self == Base
+          false
         else
-          sup == Base || !columns_hash.include?(inheritance_column)
+          [Base, Model].include?(sup) || !columns_hash.include?(inheritance_column)
         end
       end
 
@@ -81,18 +83,12 @@ module ActiveRecord
         instance
       end
 
-      # If this class includes ActiveRecord::Model then it won't have a
+      # For internal use.
-      # superclass. So this provides a way to get to the 'root' (ActiveRecord::Base),
-      # through inheritance hierarchy, ending in Base, whether or not that is
-      # actually an ancestor of the class.
       #
-      # Mainly for internal use.
+      # If this class includes ActiveRecord::Model then it won't have a
+      # superclass. So this provides a way to get to the 'root' (ActiveRecord::Model).
       def active_record_super #:nodoc:
-        if self == Base || superclass && superclass < Model
+        superclass < Model ? superclass : Model
-          superclass
-        else
-          Base
-        end
       end
 
       protected
@@ -105,7 +101,7 @@ module ActiveRecord
         end
 
         sup = klass.active_record_super
-        if klass == Base || sup == Base || sup.abstract_class?
+        if [Base, Model].include?(klass) || [Base, Model].include?(sup) || sup.abstract_class?
           klass
         else
           class_of_active_record_descendant(sup)

activerecord/lib/active_record/model.rb

@@ -22,6 +22,7 @@ module ActiveRecord
       include DynamicMatchers
       include CounterCache
       include Explain
+      include ConnectionHandling
     end
 
     def self.included(base)
@@ -40,6 +41,7 @@ module ActiveRecord
     extend ActiveModel::AttributeMethods::ClassMethods
     extend Callbacks::Register
     extend Explain
+    extend ConnectionHandling
 
     def self.extend(*modules)
       ClassMethods.send(:include, *modules)
@@ -65,6 +67,20 @@ module ActiveRecord
     include Aggregations, Transactions, Reflection, Serialization, Store
     include Core
 
+    class << self
+      def arel_engine
+        self
+      end
+
+      def abstract_class?
+        false
+      end
+
+      def inheritance_column
+        'type'
+      end
+    end
+
     module DeprecationProxy #:nodoc:
       class << self
         instance_methods.each { |m| undef_method m unless m =~ /^__|^object_id$|^instance_eval$/ }

activerecord/lib/active_record/model_schema.rb

@@ -143,11 +143,7 @@ module ActiveRecord
 
       # The name of the column containing the object's class when Single Table Inheritance is used
       def inheritance_column
-        if self == Base
+        (@inheritance_column ||= nil) || active_record_super.inheritance_column
-          'type'
-        else
-          (@inheritance_column ||= nil) || active_record_super.inheritance_column
-        end
       end
 
       # Sets the value of inheritance_column

activerecord/test/cases/base_test.rb

@@ -23,6 +23,7 @@ require 'models/edge'
 require 'models/joke'
 require 'models/bulb'
 require 'models/bird'
+require 'models/teapot'
 require 'rexml/document'
 require 'active_support/core_ext/exception'
 require 'bcrypt'
@@ -1634,10 +1635,7 @@ class BasicsTest < ActiveRecord::TestCase
   end
 
   def test_descends_from_active_record
-    # Tries to call Object.abstract_class?
+    assert !ActiveRecord::Base.descends_from_active_record?
-    assert_raise(NoMethodError) do
-      ActiveRecord::Base.descends_from_active_record?
-    end
 
     # Abstract subclass of AR::Base.
     assert LoosePerson.descends_from_active_record?
@@ -1660,6 +1658,10 @@ class BasicsTest < ActiveRecord::TestCase
 
     # Concrete subclasses an abstract class which has a type column.
     assert !SubStiPost.descends_from_active_record?
+
+    assert Teapot.descends_from_active_record?
+    assert !OtherTeapot.descends_from_active_record?
+    assert CoolTeapot.descends_from_active_record?
   end
 
   def test_find_on_abstract_base_class_doesnt_use_type_condition
@@ -1893,4 +1895,13 @@ class BasicsTest < ActiveRecord::TestCase
     Bird.stubs(:scoped).returns(mock(:uniq => scope))
     assert_equal scope, Bird.uniq
   end
+
+  def test_active_record_super
+    assert_equal ActiveRecord::Model, ActiveRecord::Base.active_record_super
+    assert_equal ActiveRecord::Base,  Topic.active_record_super
+    assert_equal Topic,               ImportantTopic.active_record_super
+    assert_equal ActiveRecord::Model, Teapot.active_record_super
+    assert_equal Teapot,              OtherTeapot.active_record_super
+    assert_equal ActiveRecord::Model, CoolTeapot.active_record_super
+  end
 end

activerecord/test/cases/connection_adapters/abstract_adapter_test.rb

@@ -35,7 +35,7 @@ module ActiveRecord
       end
 
       def test_close
-        pool = ConnectionPool.new(Base::ConnectionSpecification.new({}, nil))
+        pool = ConnectionPool.new(ConnectionSpecification.new({}, nil))
         pool.connections << adapter
         adapter.pool = pool
 

activerecord/test/cases/connection_specification/resolver_test.rb

@@ -1,7 +1,7 @@
 require "cases/helper"
 
 module ActiveRecord
-  module Core
+  module ConnectionAdapters
     class ConnectionSpecification
       class ResolverTest < ActiveRecord::TestCase
         def resolve(spec)

activerecord/test/cases/inclusion_test.rb

@@ -56,10 +56,13 @@ class InclusionUnitTest < ActiveRecord::TestCase
 
   def test_establish_connection
     assert @klass.respond_to?(:establish_connection)
+    assert ActiveRecord::Model.respond_to?(:establish_connection)
   end
 
   def test_adapter_connection
-    assert @klass.respond_to?("#{ActiveRecord::Base.connection_config[:adapter]}_connection")
+    name = "#{ActiveRecord::Base.connection_config[:adapter]}_connection"
+    assert @klass.respond_to?(name)
+    assert ActiveRecord::Model.respond_to?(name)
   end
 
   def test_connection_handler

activerecord/test/cases/inheritance_test.rb

@@ -65,7 +65,6 @@ class InheritanceTest < ActiveRecord::TestCase
   end
 
   def test_company_descends_from_active_record
-    assert_raise(NoMethodError) { ActiveRecord::Base.descends_from_active_record? }
     assert AbstractCompany.descends_from_active_record?, 'AbstractCompany should descend from ActiveRecord::Base'
     assert Company.descends_from_active_record?, 'Company should descend from ActiveRecord::Base'
     assert !Class.new(Company).descends_from_active_record?, 'Company subclass should not descend from ActiveRecord::Base'

activerecord/test/cases/unconnected_test.rb

@@ -7,13 +7,13 @@ class TestUnconnectedAdapter < ActiveRecord::TestCase
   self.use_transactional_fixtures = false
 
   def setup
-    @underlying = ActiveRecord::Base.connection
+    @underlying = ActiveRecord::Model.connection
-    @specification = ActiveRecord::Base.remove_connection
+    @specification = ActiveRecord::Model.remove_connection
   end
 
   def teardown
     @underlying = nil
-    ActiveRecord::Base.establish_connection(@specification)
+    ActiveRecord::Model.establish_connection(@specification)
     load_schema if in_memory_db?
   end
 

activerecord/test/models/teapot.rb

@@ -12,6 +12,9 @@ class Teapot
   include ActiveRecord::Model
 end
 
+class OtherTeapot < Teapot
+end
+
 class OMFGIMATEAPOT
   def aaahhh
     "mmm"

activerecord/test/schema/schema.rb

@@ -598,6 +598,7 @@ ActiveRecord::Schema.define do
 
   create_table :teapots, :force => true do |t|
     t.string :name
+    t.string :type
     t.timestamps
   end
 

activerecord/test/support/connection.rb

@@ -12,9 +12,9 @@ module ARTest
 
   def self.connect
     puts "Using #{connection_name} with Identity Map #{ActiveRecord::IdentityMap.enabled? ? 'on' : 'off'}"
-    ActiveRecord::Base.logger = ActiveSupport::Logger.new("debug.log")
+    ActiveRecord::Model.logger = ActiveSupport::Logger.new("debug.log")
-    ActiveRecord::Base.configurations = connection_config
+    ActiveRecord::Model.configurations = connection_config
-    ActiveRecord::Base.establish_connection 'arunit'
+    ActiveRecord::Model.establish_connection 'arunit'
     Course.establish_connection 'arunit2'
   end
 end