3 files changed, 56 insertions, 5 deletions

diff --git a/activerecord/lib/active_record/railties/databases.rake b/activerecord/lib/active_record/railties/databases.rake
index 93bbeea5a3..48febcbc43 100644
--- a/activerecord/lib/active_record/railties/databases.rake
+++ b/activerecord/lib/active_record/railties/databases.rake
@@ -373,7 +373,7 @@ namespace :railties do
         puts "NOTE: Migration #{migration.basename} from #{name} has been skipped. Migration with the same name already exists."
       end
 
-      on_copy = Proc.new do |name, migration, old_path|
+      on_copy = Proc.new do |name, migration|
         puts "Copied migration #{migration.basename} from #{name}"
       end
 
diff --git a/activerecord/lib/active_record/scoping.rb b/activerecord/lib/active_record/scoping.rb
index 886182f534..b631730ab3 100644
--- a/activerecord/lib/active_record/scoping.rb
+++ b/activerecord/lib/active_record/scoping.rb
@@ -9,11 +9,11 @@ module ActiveRecord
 
     module ClassMethods
       def current_scope #:nodoc:
-        Thread.current["#{base_class}_current_scope"]
+        ScopeRegistry.current.value_for(:current_scope, base_class.to_s)
       end
 
       def current_scope=(scope) #:nodoc:
-        Thread.current["#{base_class}_current_scope"] = scope
+        ScopeRegistry.current.set_value_for(:current_scope, base_class.to_s, scope)
       end
     end
 
@@ -24,5 +24,56 @@ module ActiveRecord
         send("#{att}=", value) if respond_to?("#{att}=")
       end
     end
+
+    # This class stores the +:current_scope+ and +:ignore_default_scope+ values
+    # for different classes. The registry is stored as a thread local, which is
+    # accessed through +ScopeRegistry.current+.
+    #
+    # This class allows you to store and get the scope values on different
+    # classes and different types of scopes. For example, if you are attempting
+    # to get the current_scope for the +Board+ model, then you would use the
+    # following code:
+    #
+    #   registry = ActiveRecord::Scoping::ScopeRegistry.current
+    #   registry.set_value_for(:current_scope, "Board", some_new_scope)
+    #
+    # Now when you run:
+    #
+    #   registry.value_for(:current_scope, "Board")
+    #
+    # You will obtain whatever was defined in +some_new_scope+.
+    class ScopeRegistry # :nodoc:
+      def self.current
+        Thread.current["scope_registry"] ||= new
+      end
+
+      VALID_SCOPE_TYPES = [:current_scope, :ignore_default_scope]
+
+      attr_accessor :registry
+
+      def initialize
+        @registry = Hash.new { |hash, key| hash[key] = {} }
+      end
+
+      # Obtains the value for a given +scope_name+ and +variable_name+.
+      def value_for(scope_type, variable_name)
+        raise_invalid_scope_type!(scope_type)
+        @registry[scope_type][variable_name]
+      end
+
+      # Sets the +value+ for a given +scope_type+ and +variable_name+.
+      def set_value_for(scope_type, variable_name, value)
+        raise_invalid_scope_type!(scope_type)
+        @registry[scope_type][variable_name] = value
+      end
+
+      private
+
+      def raise_invalid_scope_type!(scope_type)
+        if !VALID_SCOPE_TYPES.include?(scope_type)
+          raise ArgumentError, "Invalid scope type '#{scope_type}' sent to the registry. Scope types must be included in VALID_SCOPE_TYPES"
+        end
+      end
+    end
   end
 end
diff --git a/activerecord/lib/active_record/scoping/default.rb b/activerecord/lib/active_record/scoping/default.rb
index 8a90528ce8..daee771669 100644
--- a/activerecord/lib/active_record/scoping/default.rb
+++ b/activerecord/lib/active_record/scoping/default.rb
@@ -120,11 +120,11 @@ module ActiveRecord
         end
 
         def ignore_default_scope? # :nodoc:
-          Thread.current["#{self}_ignore_default_scope"]
+          ScopeRegistry.current.value_for(:ignore_default_scope, self)
         end
 
         def ignore_default_scope=(ignore) # :nodoc:
-          Thread.current["#{self}_ignore_default_scope"] = ignore
+          ScopeRegistry.current.set_value_for(:ignore_default_scope, self, ignore)
         end
 
         # The ignore_default_scope flag is used to prevent an infinite recursion