Allow nested attributes in associations to update values in it's owner object. Fixes a regression from 3.0.x

2 files changed, 13 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/associations/association.rb b/activerecord/lib/active_record/associations/association.rb
index d1e3ff8e38..861dda618a 100644
--- a/activerecord/lib/active_record/associations/association.rb
+++ b/activerecord/lib/active_record/associations/association.rb
@@ -230,6 +230,8 @@ module ActiveRecord
         end
 
         def build_record(attributes, options)
+          attributes = (attributes || {}).reverse_merge(creation_attributes)
+
           reflection.build_association(attributes, options) do |record|
             record.assign_attributes(
               create_scope.except(*record.changed),
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index 9215a68cfc..2d2909054d 100644
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -1776,6 +1776,7 @@ MSG
 
         attributes = new_attributes.stringify_keys
         multi_parameter_attributes = []
+        nested_parameter_attributes = []
         @mass_assignment_options = options
 
         unless options[:without_protection]
@@ -1786,12 +1787,21 @@ MSG
           if k.include?("(")
             multi_parameter_attributes << [ k, v ]
           elsif respond_to?("#{k}=")
-            send("#{k}=", v)
+            if v.is_a?(Hash)
+              nested_parameter_attributes << [ k, v ]
+            else
+              send("#{k}=", v)
+            end
           else
             raise(UnknownAttributeError, "unknown attribute: #{k}")
           end
         end
 
+        # assign any deferred nested attributes after the base attributes have been set
+        nested_parameter_attributes.each do |k,v|
+          send("#{k}=", v)
+        end
+
         @mass_assignment_options = nil
         assign_multiparameter_attributes(multi_parameter_attributes)
       end