Ensure that plugins are not loaded twice

1 files changed, 9 insertions, 0 deletions

diff --git a/railties/lib/rails/plugin.rb b/railties/lib/rails/plugin.rb
index 4dab1c0b53..22a0eb10a8 100644
--- a/railties/lib/rails/plugin.rb
+++ b/railties/lib/rails/plugin.rb
@@ -18,6 +18,10 @@ module Rails
   # root during the boot process.
   #
   class Plugin < Engine
+    def self.global_plugins
+      @global_plugins ||= []
+    end
+
     def self.inherited(base)
       raise "You cannot inherit from Rails::Plugin"
     end
@@ -28,6 +32,11 @@ module Rails
         Dir["#{path}/*"].each do |plugin_path|
           plugin = new(plugin_path)
           next unless list.include?(plugin.name) || list.include?(:all)
+          if global_plugins.include?(plugin.name)
+            warn "WARNING: plugin #{plugin.name} from #{path} was not loaded. Plugin with the same name has been already loaded."
+            next
+          end
+          global_plugins << plugin.name
           plugins << plugin
         end
       end