gistfile1.txt

class SaveFromAfterCommitBlockTest < ActiveRecord::TestCase
  class TopicWithSaveInCallback < ActiveRecord::Base
    self.table_name = :topics
    after_commit :cache_topic, :on => :create

    def cache_topic
      puts "******************* calling this stuff again #{cached.inspect}"
      unless cached
        self.cached = true
        self.save
      else
        self.cached = false
      end
    end

    def cached=(value)
      @cached = value
    end

    def cached
      puts "returning #{@cached.inspect}"
      @cached
    end
  end

  def test_after_commit_in_save
    t = TopicWithSaveInCallback.new()
    t.save
    puts "I am here"
  end
end

Using mysql with Identity Map off
Run options: 

# Running tests:

returning nil
Value is nil
.returning nil
******************* calling this stuff again nil
..............

Finished tests in 0.373179s, 40.1952 tests/s, 61.6326 assertions/s.