ThinkingSphinx and Nil Results

Have you ever gotten a result like the following when using ThinkingSphinx (by the awesome Pat Allen):

NoMethodError (undefined method `constantize' for nil:NilClass):

This error occurs when your index isn’t quite up to date and ThinkingSphinx returns results that have since been deleted from your database. To fix the problem add :retry_stale => true to your searches, like this:

Article.search('chunky bacon', :retry_stale => true)

There is more information about :retry_stale in the source code:

# If you pass :retry_stale => true to a single-model search, missing records will
# cause Thinking Sphinx to retry the query but excluding those records. Since search
# is paginated, the new search could potentially include missing records as well, so by
# default Thinking Sphinx will retry three times. Pass :retry_stale => 5 to retry five
# times, and so on. If there are still missing ids on the last retry, they are
# shown as nils.