Add console hook to force ActiveRecord::Base to be loaded when consol…

…e starts avoiding reference loops.

activerecord/lib/active_record/railtie.rb

@@ -22,6 +22,12 @@ class Railtie < Rails::Railtie
       load "active_record/railties/databases.rake"
     end
 
+    # When loading console, force ActiveRecord to be loaded to avoid cross
+    # references when loading a constant for the first time.
+    console do
+      ActiveRecord::Base
+    end
+
     initializer "active_record.initialize_timezone" do
       ActiveSupport.on_load(:active_record) do
         self.time_zone_aware_attributes = true

railties/lib/rails/application.rb

@@ -149,6 +149,13 @@ def load_generators
       self
     end
 
+    def load_console(sandbox=false)
+      initialize_console(sandbox)
+      railties.all { |r| r.load_console }
+      super()
+      self
+    end
+
     def app
       @app ||= begin
         config.middleware = config.middleware.merge_into(default_middleware_stack)
@@ -212,5 +219,11 @@ def initialize_tasks
     def initialize_generators
       require "rails/generators"
     end
+
+    def initialize_console(sandbox=false)
+      require "rails/console/app"
+      require "rails/console/sandbox" if sandbox
+      require "rails/console/helpers"
+    end
   end
 end

railties/lib/rails/commands/console.rb

@@ -23,10 +23,7 @@ def start
         opt.parse!(ARGV)
       end
 
-      @app.initialize!
-      require "rails/console/app"
-      require "rails/console/sandbox" if options[:sandbox]
-      require "rails/console/helpers"
+      @app.load_console(options[:sandbox])
 
       if options[:debugger]
         begin

railties/lib/rails/railtie.rb

@@ -156,6 +156,12 @@ def rake_tasks(&blk)
         @rake_tasks
       end
 
+      def console(&blk)
+        @load_console ||= []
+        @load_console << blk if blk
+        @load_console
+      end
+
       def generators(&blk)
         @generators ||= []
         @generators << blk if blk
@@ -170,20 +176,16 @@ def abstract_railtie?
     def eager_load!
     end
 
-    def rake_tasks
-      self.class.rake_tasks
-    end
-
-    def generators
-      self.class.generators
+    def load_console
+      self.class.console.each(&:call)
     end
 
     def load_tasks
-      rake_tasks.each { |blk| blk.call }
+      self.class.rake_tasks.each(&:call)
     end
 
     def load_generators
-      generators.each { |blk| blk.call }
+      self.class.generators.each(&:call)
     end
   end
 end

railties/test/application/console_test.rb

@@ -9,10 +9,8 @@ def setup
   end
 
   def load_environment
-    # Load steps taken from rails/commands/console.rb
     require "#{rails_root}/config/environment"
-    require 'rails/console/app'
-    require 'rails/console/helpers'
+    Rails.application.load_console
   end
 
   def test_app_method_should_return_integration_session
@@ -75,4 +73,21 @@ def test_access_to_helpers
     assert_equal 'Once upon a time in a world...',
       helper.truncate('Once upon a time in a world far far away')
   end
+
+  def test_active_record_does_not_panic_when_referencing_an_observed_constant
+    add_to_config "config.active_record.observers = :user_observer"
+
+    app_file "app/models/user.rb", <<-MODEL
+      class User < ActiveRecord::Base
+      end
+    MODEL
+
+    app_file "app/models/user_observer.rb", <<-MODEL
+      class UserObserver < ActiveRecord::Observer
+      end
+    MODEL
+
+    load_environment
+    assert_nothing_raised { User }
+  end
 end

railties/test/railties/railtie_test.rb

@@ -103,6 +103,22 @@ class MyTie < Rails::Railtie
       assert $ran_block
     end
 
+    test "console block is executed when MyApp.load_console is called" do
+      $ran_block = false
+
+      class MyTie < Rails::Railtie
+        console do
+          $ran_block = true
+        end
+      end
+
+      require "#{app_path}/config/environment"
+
+      assert !$ran_block
+      AppTemplate::Application.load_console
+      assert $ran_block
+    end
+
     test "railtie can add initializers" do
       $ran_block = false