Deprecate set_inheritance_column in favour of self.inheritance_column=

activerecord/CHANGELOG.md

@@ -1,12 +1,18 @@
 ## Rails 3.2.0 (unreleased) ##
 
-*   Deprecated `set_table_name`. Use `self.table_name=` instead, or define your own
+*   Deprecated:
-    `self.table_name` method:
+
+      * `set_table_name`
+      * `set_inheritance_column`
+
+    Use an assignment method instead. For example, instead of `set_table_name`, use `self.table_name=`:
 
          class Project < ActiveRecord::Base
            self.table_name = "project"
          end
 
+    Or define your own `self.table_name` method:
+
          class Post < ActiveRecord::Base
            def self.table_name
              "special_" + super

activerecord/lib/active_record/base.rb

@@ -702,10 +702,36 @@ module ActiveRecord #:nodoc:
         (parents.detect{ |p| p.respond_to?(:table_name_prefix) } || self).table_name_prefix
       end
 
-      # Defines the column name for use with single table inheritance. Use
+      # The name of the column containing the object's class when Single Table Inheritance is used
-      # <tt>set_inheritance_column</tt> to set a different value.
       def inheritance_column
-        @inheritance_column ||= "type"
+        if self == Base
+          'type'
+        else
+          defined?(@inheritance_column) ? @inheritance_column : superclass.inheritance_column
+        end
+      end
+
+      # Sets the value of inheritance_column
+      def inheritance_column=(value)
+        @inheritance_column = value.to_s
+      end
+
+      def set_inheritance_column(value = nil, &block) #:nodoc:
+        if block
+          ActiveSupport::Deprecation.warn(
+            "Calling set_inheritance_column is deprecated. If you need to lazily evaluate " \
+            "the inheritance column, define your own `self.inheritance_column` class method. You can use `super` " \
+            "to get the default inheritance column where you would have called `original_inheritance_column`."
+          )
+
+          define_attr_method :inheritance_column, value, &block
+        else
+          ActiveSupport::Deprecation.warn(
+            "Calling set_inheritance_column is deprecated. Please use `self.inheritance_column = 'the_name'` instead."
+          )
+
+          self.inheritance_column = value
+        end
       end
 
       # Lazy-set the sequence name to the connection's default. This method
@@ -720,20 +746,6 @@ module ActiveRecord #:nodoc:
         default
       end
 
-      # Sets the name of the inheritance column to use to the given value,
-      # or (if the value # is nil or false) to the value returned by the
-      # given block.
-      #
-      #   class Project < ActiveRecord::Base
-      #     set_inheritance_column do
-      #       original_inheritance_column + "_id"
-      #     end
-      #   end
-      def set_inheritance_column(value = nil, &block)
-        define_attr_method :inheritance_column, value, &block
-      end
-      alias :inheritance_column= :set_inheritance_column
-
       # Sets the name of the sequence to use when generating ids to the given
       # value, or (if the value is nil or false) to the value returned by the
       # given block. This is required for Oracle and is useful for any

activerecord/test/cases/base_test.rb

@@ -1495,13 +1495,18 @@ class BasicsTest < ActiveRecord::TestCase
     k = Class.new( ActiveRecord::Base )
     k.inheritance_column = "foo"
     assert_equal "foo", k.inheritance_column
+
+    assert_deprecated do
       k.set_inheritance_column "bar"
+    end
     assert_equal "bar", k.inheritance_column
   end
 
   def test_set_inheritance_column_with_block
     k = Class.new( ActiveRecord::Base )
+    assert_deprecated do
       k.set_inheritance_column { original_inheritance_column + "_id" }
+    end
     assert_equal "type_id", k.inheritance_column
   end
 

activerecord/test/cases/inheritance_test.rb

@@ -236,11 +236,11 @@ class InheritanceTest < ActiveRecord::TestCase
         c.save
       end
       [ Company, Firm, Client].each { |klass| klass.reset_column_information }
-      Company.set_inheritance_column('ruby_type')
+      Company.inheritance_column = 'ruby_type'
     end
     def switch_to_default_inheritance_column
       [ Company, Firm, Client].each { |klass| klass.reset_column_information }
-      Company.set_inheritance_column('type')
+      Company.inheritance_column = 'type'
     end
 end
 

activerecord/test/models/parrot.rb

@@ -1,5 +1,6 @@
 class Parrot < ActiveRecord::Base
-  set_inheritance_column :parrot_sti_class
+  self.inheritance_column = :parrot_sti_class
+
   has_and_belongs_to_many :pirates
   has_and_belongs_to_many :treasures
   has_many :loots, :as => :looter