Association reload fails due to cached @finder_sql

assuming that:

class Tag < ActiveRecord::Base
  has_one  :tagging

and

class Tagging < ActiveRecord::Base
  belongs_to :tag

This test fails on the second assert_equal after tag.tagging.reload

  def test_where_reload_assoc_fails
    tag = Tag.new
    ing = Tagging.new
    
    ing.tag = tag
    tag.tagging = ing
    
    tag.save!
    
    assert_equal(ing, tag.tagging)

    tag.tagging.reload

    assert_equal(ing, tag.tagging)
  end

Here is an almost identical test that passes

  def test_where_reload_assoc_works
    tag = Tag.new
    ing = Tagging.new
    
    ing.tag = tag
    tag.tagging = ing
    
    tag.save!
    
    assert_equal(ing, tag.tagging)

    tag.reload

    assert_equal(ing, tag.tagging)
  end

The problem appears to be that the tag.tagging.reload uses a cached @finder_sql which was generated when the association was first referenced (when assigning the Not yet saved "ing" object to it) At that point the finder_sql was generated to include this line:

  "#{@reflection.quoted_table_name}.#{@reflection.options[:as]}_id = #{owner_quoted_id} AND " +

And owner_quoted_id is nil at this point because "tag" is not yet saved.

So when we tag.tagging.reload we execute this bad cached SQL that says "tag_id = NULL"