ActiveRecord no longer populates uuid ids that were generated in the database

Migration

class CreatePosts < ActiveRecord::Migration
  def self.up
    execute <<-SQL
      CREATE FUNCTION uuid_generate_v1() RETURNS uuid
          LANGUAGE c STRICT
          AS '$libdir/uuid-ossp', 'uuid_generate_v1';
    
      CREATE TABLE posts (
          id character varying(36) DEFAULT uuid_generate_v1() NOT NULL,
          title character varying
      );
    SQL
  end

  def self.down
    drop_table :posts
  end
end

Model

class Post < ActiveRecord::Base
end

Test

require 'test_helper'

class PostTest < ActiveSupport::TestCase
  test "save should be true" do  # passes
    post = Post.new :title => "Foo"
    assert post.save, "Post save should be true"
  end

  test "save! should be true" do  # passes
    post = Post.new :title => "Foo"
    assert post.save!, "Post save should be true"
  end

  test "save! should change the number of records" do  # passes
    assert_difference('Post.count', 1) do
      Post.create! :title => "Foo"
    end
  end

  test "save assigns the id" do # fails!
    post = Post.create! :title => "Foo"
    assert post.id.present?, "Post should have an id"
  end
end

Gemfile

source 'http://rubygems.org'
gem 'rails', '3.0.0.rc'
gem 'pg'

I've also attached a zip file of the app that might be easier to use to reproduce. I haven't taken the time to see whether this is broken in other adapters.

I've confirmed that on a brand-new rails 2.3.8 app with an identical migration all tests pass. I've also included a zip file with that example.