Add AR::Base.base_class for querying the ancestor AR::Base subclass [Jamis Buck]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3439 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

3 files changed, 24 insertions, 5 deletions

diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index 50d22feb1c..3696d08e62 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Add AR::Base.base_class for querying the ancestor AR::Base subclass [Jamis Buck]
+
 * Allow configuration of the column used for optimistic locking [wilsonb@gmail.com]
 
 * Don't hardcode 'id' in acts as list.  [ror@philippeapril.com]
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index 00f98d51d3..bfd9daf803 100755
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -882,6 +882,13 @@ module ActiveRecord #:nodoc:
         self.allow_concurrency = value
       end
 
+      # Returns the base AR subclass that this class descends from. If A
+      # extends AR::Base, A.base_class will return A. If B descends from A
+      # through some arbitrarily deep hierarchy, B.base_class will return A.
+      def base_class
+        class_of_active_record_descendant(self)
+      end
+
       
       private
         # Finder methods must instantiate through this method to work with the single-table inheritance model
@@ -1105,17 +1112,22 @@ module ActiveRecord #:nodoc:
           end
         end
 
-        # Returns the name of the class descending directly from ActiveRecord in the inheritance hierarchy.
-        def class_name_of_active_record_descendant(klass)
+        # Returns the class descending directly from ActiveRecord in the inheritance hierarchy.
+        def class_of_active_record_descendant(klass)
           if klass.superclass == Base
-            klass.name
+            klass
           elsif klass.superclass.nil?
             raise ActiveRecordError, "#{name} doesn't belong in a hierarchy descending from ActiveRecord"
           else
-            class_name_of_active_record_descendant(klass.superclass)
+            class_of_active_record_descendant(klass.superclass)
           end
         end
 
+        # Returns the name of the class descending directly from ActiveRecord in the inheritance hierarchy.
+        def class_name_of_active_record_descendant(klass)
+          class_of_active_record_descendant(klass).name
+        end
+
         # Accepts an array or string.  The string is returned untouched, but the array has each value
         # sanitized and interpolated into the sql statement.
         #   ["name='%s' and group_id='%s'", "foo'bar", 4]  returns  "name='foo''bar' and group_id='4'"
diff --git a/activerecord/test/base_test.rb b/activerecord/test/base_test.rb
index 5c70768436..42fefa9001 100755
--- a/activerecord/test/base_test.rb
+++ b/activerecord/test/base_test.rb
@@ -1112,7 +1112,12 @@ class BasicsTest < Test::Unit::TestCase
     developers = Developer.find(:all, :order => 'id')
     assert_equal Developer.count, developers.size
   end
-  
+
+  def test_base_class
+    assert_equal LoosePerson, LoosePerson.base_class
+    assert_equal LoosePerson, LooseDescendant.base_class
+  end
+
   # FIXME: this test ought to run, but it needs to run sandboxed so that it
   # doesn't b0rk the current test environment by undefing everything.
   #