1 files changed, 60 insertions, 2 deletions
diff --git a/activerecord/lib/active_record/scoping.rb b/activerecord/lib/active_record/scoping.rb
index 9746b1c3c2..6ab36a23a7 100644
--- a/activerecord/lib/active_record/scoping.rb
+++ b/activerecord/lib/active_record/scoping.rb
@@ -1,3 +1,5 @@
+require 'active_support/per_thread_registry'
+
 module ActiveRecord
   module Scoping
     extend ActiveSupport::Concern
@@ -9,11 +11,11 @@ module ActiveRecord
 
     module ClassMethods
       def current_scope #:nodoc:
-        Thread.current["#{self}_current_scope"]
+        ScopeRegistry.value_for(:current_scope, base_class.to_s)
       end
 
       def current_scope=(scope) #:nodoc:
-        Thread.current["#{self}_current_scope"] = scope
+        ScopeRegistry.set_value_for(:current_scope, base_class.to_s, scope)
       end
     end
 
@@ -24,5 +26,61 @@ 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.instance
+    #   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+. The +value_for+
+    # and +set_value_for+ methods are delegated to the current +ScopeRegistry+
+    # object, so the above example code can also be called as:
+    #
+    #   ActiveRecord::Scoping::ScopeRegistry.set_value_for(:current_scope,
+    #       "Board", some_new_scope)
+    class ScopeRegistry # :nodoc:
+      extend ActiveSupport::PerThreadRegistry
+
+      class << self
+        delegate :value_for, :set_value_for, to: :instance
+      end
+
+      VALID_SCOPE_TYPES = [:current_scope, :ignore_default_scope]
+
+      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