Disable validations for associated belongs_to record by default

activerecord/lib/active_record/associations.rb

@@ -940,7 +940,7 @@ module ActiveRecord
           )
         end
 
-        add_single_associated_save_callbacks(reflection.name) unless options[:validate] == false
+        add_single_associated_save_callbacks(reflection.name) if options[:validate] == true
 
         configure_dependency_for_belongs_to(reflection)
       end

activerecord/test/models/developer.rb

@@ -56,8 +56,8 @@ class Developer < ActiveRecord::Base
 end
 
 class AuditLog < ActiveRecord::Base
-  belongs_to :developer
-  belongs_to :unvalidated_developer, :class_name => 'Developer', :validate => false
+  belongs_to :developer, :validate => true
+  belongs_to :unvalidated_developer, :class_name => 'Developer'
 end
 
 DeveloperSalary = Struct.new(:amount)