What's happening? Suppose you have a simple app and you want to run some tests using the test database. Not sure if this is mandatory when using the built in JRuby but it seems to be normal to use the jdbcmysql adapter. When you try to run the tests you will see something like this:
ActiveRecord::StatementInvalid: ActiveRecord::JDBCError: Table 'kontakt_test.contacts' doesn't exist: DELETE FROM `contacts`
followed by the stack trace that isn't really helpful as it's not the root cause. Rails somehow doesn't create the tables in the test database. You'll see a more helpful output when starting the rake task "db:test:prepare" directly in debug mode:
** Invoke db:test:prepare (first_time)
** Invoke db:abort_if_pending_migrations (first_time)
** Invoke environment (first_time)
** Execute environment
** Execute db:abort_if_pending_migrations
Task not supported by 'jdbcmysql'
** Execute db:test:prepare
** Invoke db:test:load (first_time)
** Invoke db:test:purge (first_time)
** Invoke environment
** Execute db:test:purge
The task fails in the database task in the rails lib. You can open up the source code by opening the node
At line 357 you can see the problem: Rails only expexts some hardcoded adapters, jdbcmysql not being one of them. It skips the task for unknown adapters. Two options to fix it: Insert a regular expression that matches both:
when /mysql/ # instead of when "mysql"
or add the jdbcmysql adapter as a second option:
Now the tests are running and hopefully passing. The same kind of error might occur for other tasks as well as there are some more checks for the mysql adapter in this file. You should be able to fix them the same way.
I wouldn't have expected to have to patch the rails code for using it in Netbeans but this doesn't seem to be uncommon. Using a recent active record version is supposed to fix the problem as you can use mysql as an adapter name then but I didn't find a way to run the jdbc generator from Netbeans. It isn't available in the list of generators and I didn't find a generator gem to download.
What's to be learned for me from this? I got a better understanding of how the build process works using rake. But more importantly: even technologies that have been hyped for a long time might not be that flawless as you would expect.