Is there a way to run a rake task without running the prerequisites?

Question

Is there a command line switch I'm missing?

At the moment I'm having to do this:

#task :install => :build do
task :install do
end

Answer 1

if you define a dependency on a task, it will always be run first. However, you can create your tasks individually and then aggregate them together with another task, like this:

task :build do
  ... 
end

task :install do
  ...
end

task :go => [:build, :install]

and then you can call the build or install tasks independently, or run the sequence with the go task.

rake build

rake install

rake go

i do this a lot, actually. it makes it very convenient for me to run individual steps when i want to, and have the larger sequence of steps when i need them.

Answer 2

I seem to have solved this problem by simply adding extra tasks in the format "taskname_no_prerequisites". So for example in the code below executing "rake install_no_prerequisites" would not cause "build" to be executed.

desc "Build"
task :build do
  puts "BUILDING..."
end

desc "Install"
task :install => :build do
  puts "INSTALLING..."
end

Rake::Task::tasks.each do |task|
  desc "#{task} without prerequisites"
  task "#{task}_no_prerequisites".to_sym do
    task.invoke_without_prerequisites
  end
end

module Rake
  class Task
    def invoke_without_prerequisites
      execute
    end  
  end
end