Merge pull request #4727 from railsaholic/dependent_restrict_should_add_error

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

6 files changed, 49 insertions, 21 deletions

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.