1 files changed, 7 insertions, 2 deletions
diff --git a/railties/lib/rails/plugin.rb b/railties/lib/rails/plugin.rb
index 394e634903..62dc7f30f8 100644
--- a/railties/lib/rails/plugin.rb
+++ b/railties/lib/rails/plugin.rb
@@ -6,8 +6,6 @@ module Rails
       raise "You cannot inherit from Rails::Plugin"
     end
 
-    # TODO Right now, if a plugin has an Engine or a Railtie inside it,
-    # the initializers for this plugin will be executed twice.
     def self.all(list, paths)
       plugins = []
       paths.each do |path|
@@ -39,5 +37,12 @@ module Rails
       config = app.config
       eval(File.read(file), binding, file) if file && File.file?(file)
     end
+
+    # TODO Write tests for this sanity check
+    initializer :sanity_check_railties_collision do
+      if Engine.subclasses.map { |k| k.root.to_s }.include?(root.to_s)
+        raise "The plugin #{name.inspect} is a Railtie or an Engine and cannot be installed as Plugin"
+      end
+    end
   end
 end