caching bugs in ActiveRecord#create and associations

Looks like this isn't just a problem with find_or_create. I can cause a similar problem with regular create. It only takes a little bit of indirection on the very same association to screw things up.

Patch added contains tests that verify the problem

I still have this issue today (Rails version 2.3.2).

The test code will explain what's wrong.

class Page < ActiveRecord::Base
  acts_as_tree :counter_cache => :children_count
end

Test:

require File.dirname(FILE) + '/../test_helper'







class PageTest < ActiveSupport::TestCase
  context "pages" do

should "have a counter cache" do
  Page.root.children_count.should == 0
  Page.root.children.create(:title => 'about')
  Page.root.children.count.should == 1
  Page.root.children_count.should == 1
  Page.root.children.find_or_create_by_title('contact')
  Page.root.children.count.should == 2
  Page.root.children_count.should == 2 # false
end

  end
end

[bulk edit]

@nickretallack Do you want to rebase your test against rails3 edge?

Just recapping.

class Car
  has_many :brakes
end

c = Car.first
c.brakes # => 0 . so that all brakes are loaded
c.brakes.find_or_create(:name => 'super_brake') # new brake is created
c.brakes.length #=> 0
c.brakes.count #=> 1

when c.brakes.find_or_create is invoked then method_missing is called and method_missing simply does

  @reflection.klass.send(method, *args) { |*block_args| yield(*block_args) }

In contrast when car.brakes.create(:name => 'super_brake') is called then add_record_to_target_with_callbacks is called

def add_record_to_target_with_callbacks(record)
   callback(:before_add, record)
   yield(record) if block_given?
   @target ||= [] unless loaded?
   @target << record unless @reflection.options[:uniq] && @target.include?(record)
   callback(:after_add, record)
   set_inverse_instance(record, @owner)
   record
 end

So not only cache is not getting refreshed but inverse_instance will also not be set.

Added a patch with fixes and tests.

(from [fad166c15277c72b370c90e890d509d0f6c9af63]) AssociationCollection#create_by*, find_or_create_by* work properly now. [#1108 caching bugs in ActiveRecord#create and associations state:resolved]

Signed-off-by: Jeremy Kemper jeremy@bitsweat.net
http://github.com/rails/rails/commit/fad166c15277c72b370c90e890d509...

Automatic cleanup of spam.

I've applied the patch to the 2-3 branch. Thanks!