Merge pull request #6936 from jfoley/callbacks

Fix collisions with before and after validation callbacks.

activemodel/lib/active_model/validations/callbacks.rb

@@ -56,7 +56,8 @@ module ActiveModel
           options = args.last
           if options.is_a?(Hash) && options[:on]
             options[:if] = Array(options[:if])
-            options[:if].unshift("self.validation_context == :#{options[:on]}")
+            options[:on] = Array(options[:on])
+            options[:if].unshift("#{options[:on]}.include? self.validation_context")
           end
           set_callback(:validation, :before, *args, &block)
         end
@@ -92,7 +93,10 @@ module ActiveModel
           options = args.extract_options!
           options[:prepend] = true
           options[:if] = Array(options[:if])
-          options[:if].unshift("self.validation_context == :#{options[:on]}") if options[:on]
+          if options[:on]
+            options[:on] = Array(options[:on])
+            options[:if].unshift("#{options[:on]}.include? self.validation_context")
+          end
           set_callback(:validation, :after, *(args << options), &block)
         end
       end

activerecord/CHANGELOG.md

@@ -1,5 +1,9 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Allow before and after validations to take an array of lifecycle events
+
+    *John Foley*
+
 *   Support for specifying transaction isolation level
 
     If your database supports setting the isolation level for a transaction, you can set

activerecord/test/cases/callbacks_test.rb

@@ -137,6 +137,32 @@ class OnCallbacksDeveloper < ActiveRecord::Base
   end
 end
 
+class ContextualCallbacksDeveloper < ActiveRecord::Base
+  self.table_name = 'developers'
+
+  before_validation { history << :before_validation }
+  before_validation :before_validation_on_create_and_update, :on => [ :create, :update ]
+
+  validate do
+    history << :validate
+  end
+
+  after_validation { history << :after_validation }
+  after_validation :after_validation_on_create_and_update, :on => [ :create, :update ]
+
+  def before_validation_on_create_and_update
+    history << "before_validation_on_#{self.validation_context}".to_sym
+  end
+
+  def after_validation_on_create_and_update
+    history << "after_validation_on_#{self.validation_context}".to_sym
+  end
+
+  def history
+    @history ||= []
+  end
+end
+
 class CallbackCancellationDeveloper < ActiveRecord::Base
   self.table_name = 'developers'
 
@@ -285,6 +311,17 @@ class CallbacksTest < ActiveRecord::TestCase
     ], david.history
   end
 
+  def test_validate_on_contextual_create
+    david = ContextualCallbacksDeveloper.create('name' => 'David', 'salary' => 1000000)
+    assert_equal [
+      :before_validation,
+      :before_validation_on_create,
+      :validate,
+      :after_validation,
+      :after_validation_on_create
+    ], david.history
+  end
+
   def test_update
     david = CallbackDeveloper.find(1)
     david.save
@@ -344,6 +381,18 @@ class CallbacksTest < ActiveRecord::TestCase
     ], david.history
   end
 
+  def test_validate_on_contextual_update
+    david = ContextualCallbacksDeveloper.find(1)
+    david.save
+    assert_equal [
+      :before_validation,
+      :before_validation_on_update,
+      :validate,
+      :after_validation,
+      :after_validation_on_update
+    ], david.history
+  end
+
   def test_destroy
     david = CallbackDeveloper.find(1)
     david.destroy

guides/source/active_record_validations_callbacks.md

@@ -995,6 +995,25 @@ class User < ActiveRecord::Base
 end
 ```
 
+Callbacks can also be registered to only fire on certain lifecycle events:
+<ruby>
+class User < ActiveRecord::Base
+  before_validation :normalize_name, :on => :create
+  
+  # :on takes an array as well
+  after_validation :set_location, :on => [ :create, :update ]
+
+  protected
+  def normalize_name
+    self.name = self.name.downcase.titleize
+  end
+
+  def set_location
+    self.location = LocationService.query(self)
+  end
+end
+</ruby>
+
 It is considered good practice to declare callback methods as protected or private. If left public, they can be called from outside of the model and violate the principle of object encapsulation.
 
 Available Callbacks