backport runner fixes to 3-2-stable

Add a runner hook to Rails::Application and Rails::Engine that requires
ActiveRecord::Base to avoid circular constant loading when using observers.

This commit backports cc7dd66, c0ba0f0 and 8d01c61.

1 files changed, 22 insertions, 0 deletions

diff --git a/railties/test/application/rake_test.rb b/railties/test/application/rake_test.rb
index ab9084df55..ddabe2f07c 100644
--- a/railties/test/application/rake_test.rb
+++ b/railties/test/application/rake_test.rb
@@ -162,5 +162,27 @@ module ApplicationTests
         end
       end
     end
+
+    def test_load_activerecord_base_when_we_use_observers
+      Dir.chdir(app_path) do
+        `bundle exec rails g model user;
+         bundle exec rake db:migrate;
+         bundle exec rails g observer user;`
+
+        add_to_config "config.active_record.observers = :user_observer"
+
+        assert_equal "0", `bundle exec rails r "puts User.count"`.strip
+
+        app_file "lib/tasks/count_user.rake", <<-RUBY
+          namespace :user do
+            task :count => :environment do
+              puts User.count
+            end
+          end
+        RUBY
+
+        assert_equal "0", `bundle exec rake user:count`.strip
+      end
+    end
   end
 end