Hack to Learn

If you are getting an error message like this:

ActiveRecord::StatementInvalid: Mysql::Error: Table configurable_settings doesn't exist

… when trying to use Jacob Radford’s http://agilewebdevelopment.com/plugins/acts_as_configurable

Just do this:

./script/console development ConfigurableSetting.create_table

Of course replace ‘development’ above with whatever environment you need.

If you are experiencing the error: “undefined class/module MyClass” when fetching data from memcached, be assured that you are not alone. It is a known bug and the simplest way I know of to get around it is to reference the class or classes right before you retrieve data from the cache.

For example, if the following code causes the problem:

if not (genres = Cache.get(key))
  genres = Genre.find(:all, :condition => "platform_id = 1")
  Cache.put(key, genres, 60*60*24) # cache for 1 day
end

… then this code will work around it:

Genre
if not (genres = Cache.get(key))
  genres = Genre.find(:all, :condition => "platform_id = 1")
  Cache.put(key, genres, 60*60*24) # cache for 1 day
end

Notice the ‘Genre’ reference before the if statement. Some have reported success by using the ‘model’ statement within the controller, however that is deprecated. This workaround will get you going again.

Come on guys, we should be past stupid upstream inconsistencies like this by now.

After reading all of the worthless posts regarding this error on Gentoo , I came up with the following solution:

sudo ln -s /usr/lib/libdbus-1.so.3 /usr/lib/libdbus-1.so.2

This error seems to rear its head on other platforms as well. I’m not sure if this solution will work on other platforms.

Just do it and be done.

UPDATE: Someone from the Gentoo team tried to leave a berating comment telling me to “read the _blank_ manual” and find that revdep_rebuild solves this problem. In response I can say that it indeed does NOT solve the problem. This is a really stupid bug in Gentoo and should be fixed. Come on guys! I love the product, but this is just retarded. It isn’t that difficult to fix the problem. Just do it once and for all. The amazing thing is that I still get emails and thanks for this resolution, even in Sabayon. I’m not sure who is responsible for this incompetency on the Gentoo team but there is simply no excuse.

revdep_rebuild!?!?! Only an amateur would think that nobody has tried that first.