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.

4 files changed, 27 insertions, 0 deletions

diff --git a/railties/lib/rails/application.rb b/railties/lib/rails/application.rb
index 854ac2cbbc..cc53009e80 100644
--- a/railties/lib/rails/application.rb
+++ b/railties/lib/rails/application.rb
@@ -154,6 +154,14 @@ module Rails
       self
     end
 
+    # Load the application runner and invoke the registered hooks.
+    # Check <tt>Rails::Railtie.runner</tt> for more info.
+    def load_runner(app=self)
+      initialize_runner
+      super
+      self
+    end
+
     # Rails.application.env_config stores some of the Rails initial environment parameters.
     # Currently stores:
     #
@@ -305,6 +313,9 @@ module Rails
       require "rails/console/helpers"
     end
 
+    def initialize_runner #:nodoc:
+    end
+
     def build_original_fullpath(env)
       path_info    = env["PATH_INFO"]
       query_string = env["QUERY_STRING"]
diff --git a/railties/lib/rails/commands/runner.rb b/railties/lib/rails/commands/runner.rb
index e8cc5d9e3b..a694218695 100644
--- a/railties/lib/rails/commands/runner.rb
+++ b/railties/lib/rails/commands/runner.rb
@@ -42,6 +42,7 @@ ENV["RAILS_ENV"] = options[:environment]
 
 require APP_PATH
 Rails.application.require_environment!
+ Rails.application.load_runner
 
 if code_or_file.nil?
   $stderr.puts "Run '#{$0} -h' for help."
diff --git a/railties/lib/rails/engine.rb b/railties/lib/rails/engine.rb
index 993dfe43ee..77f335e45f 100644
--- a/railties/lib/rails/engine.rb
+++ b/railties/lib/rails/engine.rb
@@ -430,6 +430,11 @@ module Rails
       super
     end
 
+    def load_runner(app=self)
+      railties.all { |r| r.load_runner(app) }
+      super
+    end
+
     def eager_load!
       railties.all(&:eager_load!)
 
diff --git a/railties/lib/rails/railtie.rb b/railties/lib/rails/railtie.rb
index 07a122e7d0..9eb7e7c65d 100644
--- a/railties/lib/rails/railtie.rb
+++ b/railties/lib/rails/railtie.rb
@@ -145,6 +145,12 @@ module Rails
         @load_console
       end
 
+      def runner(&blk)
+        @load_runner ||= []
+        @load_runner << blk if blk
+        @load_runner
+      end
+
       def generators(&blk)
         @generators ||= []
         @generators << blk if blk
@@ -179,6 +185,10 @@ module Rails
       self.class.console.each { |block| block.call(app) }
     end
 
+    def load_runner(app=self)
+      self.class.runner.each { |block| block.call(app) }
+    end
+
     def load_tasks(app=self)
       extend Rake::DSL if defined? Rake::DSL
       self.class.rake_tasks.each { |block| self.instance_exec(app, &block) }