3 files changed, 4 insertions, 5 deletions
diff --git a/activerecord/lib/active_record/integration.rb b/activerecord/lib/active_record/integration.rb
index 441237da1e..32362fa86f 100644
--- a/activerecord/lib/active_record/integration.rb
+++ b/activerecord/lib/active_record/integration.rb
@@ -110,7 +110,6 @@ module ActiveRecord
       end
     end
 
-
     module ClassMethods
       # Defines your model's +to_param+ method to generate "pretty" URLs
       # using +method_name+, which can be any attribute or method that
diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index 1a9e0a4a40..65fdbc2fe4 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -199,7 +199,7 @@ module ActiveRecord
       def klass_join_scope(table, predicate_builder) # :nodoc:
         if klass.current_scope
           klass.current_scope.clone.tap { |scope|
-            scope.joins_values = []
+            scope.joins_values = scope.left_outer_joins_values = [].freeze
           }
         else
           relation = ActiveRecord::Relation.create(
diff --git a/activerecord/lib/active_record/tasks/database_tasks.rb b/activerecord/lib/active_record/tasks/database_tasks.rb
index c53dee43d7..ba686fc562 100644
--- a/activerecord/lib/active_record/tasks/database_tasks.rb
+++ b/activerecord/lib/active_record/tasks/database_tasks.rb
@@ -71,9 +71,9 @@ module ActiveRecord
         @tasks[pattern] = task
       end
 
-      register_task(/mysql/,        'ActiveRecord::Tasks::MySQLDatabaseTasks')
-      register_task(/postgresql/,   'ActiveRecord::Tasks::PostgreSQLDatabaseTasks')
-      register_task(/sqlite/,       'ActiveRecord::Tasks::SQLiteDatabaseTasks')
+      register_task(/mysql/,        "ActiveRecord::Tasks::MySQLDatabaseTasks")
+      register_task(/postgresql/,   "ActiveRecord::Tasks::PostgreSQLDatabaseTasks")
+      register_task(/sqlite/,       "ActiveRecord::Tasks::SQLiteDatabaseTasks")
 
       def db_dir
         @db_dir ||= Rails.application.config.paths["db"].first