Merge pull request #4727 from railsaholic/dependent_restrict_should_add_error

has_many/has_one, :dependent => :restrict, deprecation added

11 files changed, 157 insertions, 35 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index b45aba6bb1..e9e97f5d62 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,5 +1,24 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Added deprecation for the `:dependent => :restrict` association option.
+
+    Please note:
+
+      * Up until now `has_many` and `has_one`, `:dependent => :restrict`
+        option raised a `DeleteRestrictionError` at the time of destroying
+        the object. Instead, it will add an error on the model.
+
+      * To fix this warning, make sure your code isn't relying on a
+        `DeleteRestrictionError` and then add
+        `config.active_record.dependent_restrict_raises = false` to your
+        application config.
+
+      * New rails application would be generated with the
+        `config.active_record.dependent_restrict_raises = false` in the
+        application config.
+
+    *Manoj Kumar*
+
 *   Added `create_join_table` migration helper to create HABTM join tables
 
         create_join_table :products, :categories
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index 58725246c8..958821add6 100644
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -1097,8 +1097,8 @@ module ActiveRecord
       #   alongside this object by calling their +destroy+ method. If set to <tt>:delete_all</tt> all associated
       #   objects are deleted *without* calling their +destroy+ method. If set to <tt>:nullify</tt> all associated
       #   objects' foreign keys are set to +NULL+ *without* calling their +save+ callbacks. If set to
-      #   <tt>:restrict</tt> this object raises an <tt>ActiveRecord::DeleteRestrictionError</tt> exception and
-      #   cannot be deleted if it has any associated objects.
+      #   <tt>:restrict</tt> an error will be added to the object, preventing its deletion, if any associated 
+      #   objects are present.
       #
       #   If using with the <tt>:through</tt> option, the association on the join model must be
       #   a +belongs_to+, and the records which get deleted are the join records, rather than
@@ -1251,8 +1251,8 @@ module ActiveRecord
       #   If set to <tt>:destroy</tt>, the associated object is destroyed when this object is. If set to
       #   <tt>:delete</tt>, the associated object is deleted *without* calling its destroy method.
       #   If set to <tt>:nullify</tt>, the associated object's foreign key is set to +NULL+.
-      #   Also, association is assigned. If set to <tt>:restrict</tt> this object raises an
-      #   <tt>ActiveRecord::DeleteRestrictionError</tt> exception and cannot be deleted if it has any associated object.
+      #   If set to <tt>:restrict</tt>, an error will be added to the object, preventing its deletion, if an
+      #   associated object is present.
       # [:foreign_key]
       #   Specify the foreign key used for the association. By default this is guessed to be the name
       #   of this class in lower-case and "_id" suffixed. So a Person class that makes a +has_one+ association
diff --git a/activerecord/lib/active_record/associations/builder/association.rb b/activerecord/lib/active_record/associations/builder/association.rb
index 6e2e5f9de0..ba2fcf5ed7 100644
--- a/activerecord/lib/active_record/associations/builder/association.rb
+++ b/activerecord/lib/active_record/associations/builder/association.rb
@@ -51,5 +51,34 @@ module ActiveRecord::Associations::Builder
           association(name).writer(value)
         end
       end
-  end
+
+      def dependent_restrict_raises?
+        ActiveRecord::Base.dependent_restrict_raises == true
+      end
+
+      def dependent_restrict_deprecation_warning
+        if dependent_restrict_raises?
+          msg = "In the next release, `:dependent => :restrict` will not raise a `DeleteRestrictionError`."\
+                "Instead, it will add an error on the model. To fix this warning, make sure your code" \
+                "isn't relying on a `DeleteRestrictionError` and then add" \
+                "`config.active_record.dependent_restrict_raises = false` to your application config."
+          ActiveSupport::Deprecation.warn msg
+        end
+      end
+
+      def define_restrict_dependency_method
+        name = self.name
+        mixin.redefine_method(dependency_method_name) do
+          # has_many or has_one associations
+          if send(name).respond_to?(:exists?) ? send(name).exists? : !send(name).nil?
+            if dependent_restrict_raises?
+              raise ActiveRecord::DeleteRestrictionError.new(name)
+            else
+              errors.add(:base, :restrict_dependent_destroy, :model => name.to_s.singularize)
+              return false
+            end
+          end
+        end
+      end
+   end
 end
diff --git a/activerecord/lib/active_record/associations/builder/has_many.rb b/activerecord/lib/active_record/associations/builder/has_many.rb
index fc6799fb15..9ddfd433e4 100644
--- a/activerecord/lib/active_record/associations/builder/has_many.rb
+++ b/activerecord/lib/active_record/associations/builder/has_many.rb
@@ -21,6 +21,7 @@ module ActiveRecord::Associations::Builder
                                  ":nullify or :restrict (#{options[:dependent].inspect})"
           end
 
+          dependent_restrict_deprecation_warning if options[:dependent] == :restrict
           send("define_#{options[:dependent]}_dependency_method")
           model.before_destroy dependency_method_name
         end
@@ -52,13 +53,6 @@ module ActiveRecord::Associations::Builder
         end
       end
 
-      def define_restrict_dependency_method
-        name = self.name
-        mixin.redefine_method(dependency_method_name) do
-          raise ActiveRecord::DeleteRestrictionError.new(name) unless send(name).empty?
-        end
-      end
-
       def dependency_method_name
         "has_many_dependent_for_#{name}"
       end
diff --git a/activerecord/lib/active_record/associations/builder/has_one.rb b/activerecord/lib/active_record/associations/builder/has_one.rb
index 7a6cd3890f..bc8a212bee 100644
--- a/activerecord/lib/active_record/associations/builder/has_one.rb
+++ b/activerecord/lib/active_record/associations/builder/has_one.rb
@@ -34,15 +34,12 @@ module ActiveRecord::Associations::Builder
                                  ":nullify or :restrict (#{options[:dependent].inspect})"
           end
 
+          dependent_restrict_deprecation_warning if options[:dependent] == :restrict
           send("define_#{options[:dependent]}_dependency_method")
           model.before_destroy dependency_method_name
         end
       end
 
-      def dependency_method_name
-        "has_one_dependent_#{options[:dependent]}_for_#{name}"
-      end
-
       def define_destroy_dependency_method
         name = self.name
         mixin.redefine_method(dependency_method_name) do
@@ -52,11 +49,8 @@ module ActiveRecord::Associations::Builder
       alias :define_delete_dependency_method :define_destroy_dependency_method
       alias :define_nullify_dependency_method :define_destroy_dependency_method
 
-      def define_restrict_dependency_method
-        name = self.name
-        mixin.redefine_method(dependency_method_name) do
-          raise ActiveRecord::DeleteRestrictionError.new(name) unless send(name).nil?
-        end
+      def dependency_method_name
+        "has_one_dependent_#{options[:dependent]}_for_#{name}"
       end
   end
 end
diff --git a/activerecord/lib/active_record/core.rb b/activerecord/lib/active_record/core.rb
index a774af6024..a2ce620354 100644
--- a/activerecord/lib/active_record/core.rb
+++ b/activerecord/lib/active_record/core.rb
@@ -72,6 +72,16 @@ module ActiveRecord
       # The connection handler
       config_attribute :connection_handler
       self.connection_handler = ConnectionAdapters::ConnectionHandler.new
+
+      ##
+      # :singleton-method:
+      # Specifies wether or not has_many or has_one association option
+      # :dependent => :restrict raises an exception. If set to true, the
+      # ActiveRecord::DeleteRestrictionError exception will be raised
+      # along with a DEPRECATION WARNING. If set to false, an error would
+      # be added to the model instead.
+      config_attribute :dependent_restrict_raises, :global => true
+      self.dependent_restrict_raises = true
     end
 
     module ClassMethods
diff --git a/activerecord/lib/active_record/locale/en.yml b/activerecord/lib/active_record/locale/en.yml
index 44328f63b6..8892f7ef2f 100644
--- a/activerecord/lib/active_record/locale/en.yml
+++ b/activerecord/lib/active_record/locale/en.yml
@@ -10,6 +10,7 @@ en:
       messages:
         taken: "has already been taken"
         record_invalid: "Validation failed: %{errors}"
+        restrict_dependent_destroy: "Cannot delete record because dependent %{model} exists"
         # Append your own errors here or at the model/attributes scope.
 
       # You can define own errors for models or model attributes.
diff --git a/activerecord/test/cases/associations/has_many_associations_test.rb b/activerecord/test/cases/associations/has_many_associations_test.rb
index f1a341437f..8c7956406a 100644
--- a/activerecord/test/cases/associations/has_many_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_associations_test.rb
@@ -1140,16 +1140,41 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     assert_nil companies(:leetsoft).reload.client_of
     assert_nil companies(:jadedpixel).reload.client_of
 
-
     assert_equal num_accounts, Account.count
   end
 
   def test_restrict
-    firm = RestrictedFirm.new(:name => 'restrict')
-    firm.save!
+    # ActiveRecord::Base.dependent_restrict_raises = true, by default
+
+    firm = RestrictedFirm.create!(:name => 'restrict')
     firm.companies.create(:name => 'child')
+
     assert !firm.companies.empty?
     assert_raise(ActiveRecord::DeleteRestrictionError) { firm.destroy }
+    assert RestrictedFirm.exists?(:name => 'restrict')
+    assert firm.companies.exists?(:name => 'child')
+  end
+
+  def test_restrict_when_dependent_restrict_raises_config_set_to_false
+    # ActiveRecord::Base.dependent_restrict_raises = true, by default
+
+    ActiveRecord::Base.dependent_restrict_raises = false
+    # add an error on the model instead of raising ActiveRecord::DeleteRestrictionError
+
+    firm = RestrictedFirm.create!(:name => 'restrict')
+    firm.companies.create(:name => 'child')
+
+    assert !firm.companies.empty?
+
+    firm.destroy
+
+    assert !firm.errors.empty?
+
+    assert_equal "Cannot delete record because dependent company exists", firm.errors[:base].first
+    assert RestrictedFirm.exists?(:name => 'restrict')
+    assert firm.companies.exists?(:name => 'child')
+  ensure
+    ActiveRecord::Base.dependent_restrict_raises = true
   end
 
   def test_included_in_collection
@@ -1401,29 +1426,29 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
       firm.clients.last
     end
   end
-  
+
   def test_custom_primary_key_on_new_record_should_fetch_with_query
     author = Author.new(:name => "David")
     assert !author.essays.loaded?
-    
-    assert_queries 1 do 
+
+    assert_queries 1 do
       assert_equal 1, author.essays.size
     end
-    
+
     assert_equal author.essays, Essay.find_all_by_writer_id("David")
-    
+
   end
-  
+
   def test_has_many_custom_primary_key
     david = authors(:david)
     assert_equal david.essays, Essay.find_all_by_writer_id("David")
   end
-  
+
   def test_blank_custom_primary_key_on_new_record_should_not_run_queries
     author = Author.new
     assert !author.essays.loaded?
-    
-    assert_queries 0 do 
+
+    assert_queries 0 do
       assert_equal 0, author.essays.size
     end
   end
@@ -1649,4 +1674,11 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     assert_equal [bulb2], car.bulbs
     assert_equal [bulb2], car.reload.bulbs
   end
+
+  def test_building_has_many_association_with_restrict_dependency
+    klass = Class.new(ActiveRecord::Base)
+    
+    assert_deprecated     { klass.has_many :companies, :dependent => :restrict }  
+    assert_not_deprecated { klass.has_many :companies }
+  end
 end
diff --git a/activerecord/test/cases/associations/has_one_associations_test.rb b/activerecord/test/cases/associations/has_one_associations_test.rb
index 26931e3e85..7c6736fb95 100644
--- a/activerecord/test/cases/associations/has_one_associations_test.rb
+++ b/activerecord/test/cases/associations/has_one_associations_test.rb
@@ -157,11 +157,37 @@ class HasOneAssociationsTest < ActiveRecord::TestCase
   end
 
   def test_dependence_with_restrict
-    firm = RestrictedFirm.new(:name => 'restrict')
-    firm.save!
+    # ActiveRecord::Base.dependent_restrict_raises = true, by default
+
+    firm = RestrictedFirm.create!(:name => 'restrict')
     firm.create_account(:credit_limit => 10)
+
     assert_not_nil firm.account
+
     assert_raise(ActiveRecord::DeleteRestrictionError) { firm.destroy }
+    assert RestrictedFirm.exists?(:name => 'restrict')
+    assert firm.account.present?
+  end
+
+  def test_dependence_with_restrict_with_dependent_restrict_raises_config_set_to_false
+    # ActiveRecord::Base.dependent_restrict_raises = true, by default
+
+    ActiveRecord::Base.dependent_restrict_raises = false
+    # adds an error on the model instead of raising ActiveRecord::DeleteRestrictionError
+
+    firm = RestrictedFirm.create!(:name => 'restrict')
+    firm.create_account(:credit_limit => 10)
+
+    assert_not_nil firm.account
+
+    firm.destroy
+
+    assert !firm.errors.empty?
+    assert_equal "Cannot delete record because dependent account exists", firm.errors[:base].first
+    assert RestrictedFirm.exists?(:name => 'restrict')
+    assert firm.account.present?
+  ensure
+    ActiveRecord::Base.dependent_restrict_raises = true
   end
 
   def test_successful_build_association
@@ -456,4 +482,11 @@ class HasOneAssociationsTest < ActiveRecord::TestCase
 
     assert_equal car.id, bulb.attributes_after_initialize['car_id']
   end
+
+  def test_building_has_one_association_with_dependent_restrict
+    klass = Class.new(ActiveRecord::Base)
+    
+    assert_deprecated     { klass.has_one :account, :dependent => :restrict }
+    assert_not_deprecated { klass.has_one :account }
+  end
 end
diff --git a/railties/lib/rails/generators/rails/app/templates/config/application.rb b/railties/lib/rails/generators/rails/app/templates/config/application.rb
index 3517956e4a..c3a87d30b4 100644
--- a/railties/lib/rails/generators/rails/app/templates/config/application.rb
+++ b/railties/lib/rails/generators/rails/app/templates/config/application.rb
@@ -56,6 +56,11 @@ module <%= app_const_base %>
     # parameters by using an attr_accessible or attr_protected declaration.
     # config.active_record.whitelist_attributes = true
 
+    # Specifies wether or not has_many or has_one association option :dependent => :restrict raises
+    # an exception. If set to true, then an ActiveRecord::DeleteRestrictionError exception would be
+    # raised. If set to false, then an error will be added on the model instead.
+    config.active_record.dependent_restrict_raises = false
+
 <% unless options.skip_sprockets? -%>
     # Enable the asset pipeline.
     config.assets.enabled = true
diff --git a/railties/test/generators/app_generator_test.rb b/railties/test/generators/app_generator_test.rb
index f3071843e2..33a51fe782 100644
--- a/railties/test/generators/app_generator_test.rb
+++ b/railties/test/generators/app_generator_test.rb
@@ -349,6 +349,11 @@ class AppGeneratorTest < Rails::Generators::TestCase
     end
   end
 
+  def test_active_record_dependent_restrict_raises_is_present_application_config
+    run_generator
+    assert_file "config/application.rb", /config\.active_record\.dependent_restrict_raises = false/
+  end
+
 protected
 
   def action(*args, &block)