Overriding rails' default rake tasks

Question

I have a Rails 2.2 project in which I want to override the functionality of the rake db:test:prepare task. I thought this would work, but it doesn't:

#lib/tasks/db.rake
namespace :db do
  namespace :test do
    desc "Overridden version of rails' standard db:test:prepare task since the schema dump used in that can't handle DB enums"  
    task :prepare => [:environment] do
      puts "doing db:structure:dump"
      Rake::Task['db:structure:dump'].invoke
      puts "doing db:test:clone_structure"
      Rake::Task['db:test:clone_structure'].invoke
    end   
  end
end

I get the standard task's behaviour. If I change the name of the task to :prepare2 and then do rake db:test:prepare2, then it works fine. The natural conclusion I draw from this is that my rake tasks are being defined before the built-in Rails ones, so mine is overridden by the standard :prepare task.

Can anyone see how I can fix this? I'd rather override it than have to use a new task. Thanks, max

Answer 1

If you define a rake task that already exists, its execution gets appended to the original task's execution; both tasks will be executed.

If you want to redefine a task you need to clear the original task first:

Rake::Task["db:test:prepare"].clear

It's also useful to note that once a task has been executed in rake, it won't execute again even if you call it again. This is by design but you can call .reset on a task to allow it to be run again.