From 51390b8524a644aa8655691fc7bf56e2a174d140 Mon Sep 17 00:00:00 2001
From: David Heinemeier Hansson <david@loudthinking.com>
Date: Sat, 15 Jan 2005 17:52:08 +0000
Subject: [PATCH] Added validates_associated that enables validation of objects
 in an unsaved association #398 [Tim Bates]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@418 5ecf4fe2-1ee6-0310-87b1-e25e094e27de
---
 activerecord/CHANGELOG                        |  9 +++++
 activerecord/lib/active_record/validations.rb | 33 +++++++++++++++++++
 activerecord/test/validations_test.rb         | 21 ++++++++++++
 3 files changed, 63 insertions(+)

diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index d43e6a0537c96..ba5cf01178639 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,14 @@
 *SVN*
 
+* Added validates_associated that enables validation of objects in an unsaved association #398 [Tim Bates]. Example:
+
+    class Book < ActiveRecord::Base
+      has_many :pages
+      belongs_to :library
+    
+      validates_associated :pages, :library
+    end
+    
 * Added support for associating unsaved objects #402 [Tim Bates]. Rules that govern this addition:
 
     == Unsaved objects and associations
diff --git a/activerecord/lib/active_record/validations.rb b/activerecord/lib/active_record/validations.rb
index 1da73d6dc56e6..d4f75052d38d6 100755
--- a/activerecord/lib/active_record/validations.rb
+++ b/activerecord/lib/active_record/validations.rb
@@ -271,6 +271,39 @@ def validates_inclusion_of(*attr_names)
           end
         end
       end
+
+      # Validates whether the associated object or objects are all themselves valid. Works with any kind of assocation.
+      #
+      #   class Book < ActiveRecord::Base
+      #     has_many :pages
+      #     belongs_to :library
+      #
+      #     validates_associated :pages, :library
+      #   end
+      #
+      # Warning: If, after the above definition, you then wrote:
+      #
+      #   class Page < ActiveRecord::Base
+      #     belongs_to :book
+      #
+      #     validates_associated :book
+      #   end
+      #
+      # this would specify a circular dependency and cause infinite recursion. The Rails team recommends against this practice.
+      #
+      # Configuration options:
+      # * <tt>on</tt> Specifies when this validation is active (default is :save, other options :create, :update)
+      def validates_associated(*attr_names)
+        configuration = { :message => ActiveRecord::Errors.default_error_messages[:invalid], :on => :save }
+        configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash)
+        
+        for attr_name in attr_names
+          class_eval(%(#{validation_method(configuration[:on])} %{
+            errors.add("#{attr_name}", "#{configuration[:message]}") unless
+              (#{attr_name}.is_a?(Array) ? #{attr_name} : [#{attr_name}]).inject(true){ |memo, record| memo and (record.nil? or record.valid?) }
+          }))
+        end
+      end
       
 
       private
diff --git a/activerecord/test/validations_test.rb b/activerecord/test/validations_test.rb
index ed9d76bd3e68f..052cf3d6ca5cf 100755
--- a/activerecord/test/validations_test.rb
+++ b/activerecord/test/validations_test.rb
@@ -389,6 +389,27 @@ def test_validates_length_of_custom_errors_for_is_with_wrong_length
     assert_equal "hoo 5", t.errors["title"]
   end
 
+  def test_validates_associated_many
+    Topic.validates_associated( :replies )
+    t = Topic.create("title" => "uhohuhoh", "content" => "whatever")
+    t.replies << [r = Reply.create("title" => "A reply"), Reply.create("title" => "Another reply", "content" => "with content!")]
+    assert !t.valid?
+    assert t.errors.on(:replies)
+    r.content = "non-empty"
+    assert t.valid?
+  end
+
+  def test_validates_associated_one
+    Reply.validates_associated( :topic )
+    Topic.validates_presence_of( :content )
+    r = Reply.create("title" => "A reply", "content" => "with content!")
+    r.topic = Topic.create("title" => "uhohuhoh")
+    assert !r.valid?
+    assert r.errors.on(:topic)
+    r.topic.content = "non-empty"
+    assert r.valid?
+  end
+
   def test_throw_away_typing
     d = Developer.create "name" => "David", "salary" => "100,000"
     assert !d.valid?