Merge pull request #27490 from kamipo/should_not_update_children_when…

…_parent_creation_with_no_reason

Should not update children when the parent creation with no reason

activerecord/lib/active_record/associations/has_many_through_association.rb

@@ -38,10 +38,12 @@ def concat_records(records)
       def insert_record(record, validate = true, raise = false)
         ensure_not_nested
 
-        if raise
-          record.save!(:validate => validate)
-        else
-          return unless record.save(:validate => validate)
+        if record.new_record? || record.has_changes_to_save?
+          if raise
+            record.save!(validate: validate)
+          else
+            return unless record.save(validate: validate)
+          end
         end
 
         save_through_record(record)

activerecord/test/cases/autosave_association_test.rb

@@ -1390,6 +1390,14 @@ def test_should_update_children_when_autosave_is_true_and_parent_is_new_but_chil
     assert_equal "Squawky", parrot.reload.name
   end
 
+  def test_should_not_update_children_when_parent_creation_with_no_reason
+    parrot = Parrot.create!(name: "Polly")
+    assert_equal 0, parrot.updated_count
+
+    Pirate.create!(parrot_ids: [parrot.id], catchphrase: "Arrrr")
+    assert_equal 0, parrot.reload.updated_count
+  end
+
   def test_should_automatically_validate_the_associated_models
     @pirate.send(@association_name).each { |child| child.name = '' }
 

activerecord/test/models/parrot.rb

@@ -13,6 +13,11 @@ class Parrot < ActiveRecord::Base
   def cancel_save_callback_method
     throw(:abort)
   end
+
+  before_update :increment_updated_count
+  def increment_updated_count
+    self.updated_count += 1
+  end
 end
 
 class LiveParrot < Parrot

activerecord/test/schema/schema.rb

@@ -568,6 +568,7 @@
     t.column :color, :string
     t.column :parrot_sti_class, :string
     t.column :killer_id, :integer
+    t.column :updated_count, :integer, default: 0
     if subsecond_precision_supported?
       t.column :created_at, :datetime, precision: 0
       t.column :created_on, :datetime, precision: 0