Restore the use of `#add_to_target` for nested attribute updates on existing records, and don't bother updating the association if the update is going to be rejected anyway.

This requires adding a `skip_callbacks` argument to `#add_to_target`
so that we don't call the callbacks multiple times in this case,
which is functionally an application of existing association data,
rather than an addition of a new record to the association.

1 files changed, 4 insertions, 4 deletions

diff --git a/activerecord/lib/active_record/associations/collection_association.rb b/activerecord/lib/active_record/associations/collection_association.rb
index 8ce02afef8..228c500f0a 100644
--- a/activerecord/lib/active_record/associations/collection_association.rb
+++ b/activerecord/lib/active_record/associations/collection_association.rb
@@ -290,7 +290,7 @@ module ActiveRecord
 
       # Returns true if the collection is empty.
       #
-      # If the collection has been loaded 
+      # If the collection has been loaded
       # it is equivalent to <tt>collection.size.zero?</tt>. If the
       # collection has not been loaded, it is equivalent to
       # <tt>collection.exists?</tt>. If the collection has not already been
@@ -366,8 +366,8 @@ module ActiveRecord
         target
       end
 
-      def add_to_target(record)
-        callback(:before_add, record)
+      def add_to_target(record, skip_callbacks = false)
+        callback(:before_add, record) unless skip_callbacks
         yield(record) if block_given?
 
         if association_scope.distinct_value && index = @target.index(record)
@@ -376,7 +376,7 @@ module ActiveRecord
           @target << record
         end
 
-        callback(:after_add, record)
+        callback(:after_add, record) unless skip_callbacks
         set_inverse_instance(record)
 
         record