Rake des not know how to build task 'compile', how to track this error?

Question

I get the error "Don't know how to build task 'compile'". Im still new to ruby, but but all those traces seem to point to code i didnt wrote, so what should i do on this error?

#> rake compile --trace
rake aborted!
Don't know how to build task 'compile'
/usr/local/rvm/gems/ruby-1.9.3-p286/gems/rake-10.0.3/lib/rake/task_manager.rb:49:in `[]'
/usr/local/rvm/gems/ruby-1.9.3-p286/gems/rake-10.0.3/lib/rake/application.rb:142:in `invoke_task'
/usr/local/rvm/gems/ruby-1.9.3-p286/gems/rake-10.0.3/lib/rake/application.rb:101:in `block (2 levels) in top_level'
/usr/local/rvm/gems/ruby-1.9.3-p286/gems/rake-10.0.3/lib/rake/application.rb:101:in `each'
/usr/local/rvm/gems/ruby-1.9.3-p286/gems/rake-10.0.3/lib/rake/application.rb:101:in `block in top_level'
/usr/local/rvm/gems/ruby-1.9.3-p286/gems/rake-10.0.3/lib/rake/application.rb:110:in `run_with_threads'
/usr/local/rvm/gems/ruby-1.9.3-p286/gems/rake-10.0.3/lib/rake/application.rb:95:in `top_level'
/usr/local/rvm/gems/ruby-1.9.3-p286/gems/rake-10.0.3/lib/rake/application.rb:73:in `block in run'
/usr/local/rvm/gems/ruby-1.9.3-p286/gems/rake-10.0.3/lib/rake/application.rb:160:in `standard_exception_handling'
/usr/local/rvm/gems/ruby-1.9.3-p286/gems/rake-10.0.3/lib/rake/application.rb:70:in `run'
/usr/local/rvm/gems/ruby-1.9.3-p286/gems/rake-10.0.3/bin/rake:33:in `'
/usr/local/rvm/gems/ruby-1.9.3-p286/bin/rake:23:in `load'
/usr/local/rvm/gems/ruby-1.9.3-p286/bin/rake:23:in `'

this is the Rakefile:

require 'bundler/gem_tasks'
require 'rake'
require 'rake/extensiontask'
$myDir = File.dirname(__FILE__)

require $myDir + '/lib/Q/console.rb'
require $myDir + '/lib/Q/version.rb'
require $myDir + '/lib/Q/rakeoverride.rb'
require $myDir + '/lib/Q/filetools.rb'

# this just prints out a header and gems version number
puts Q::Console.txHead('Q-Pool Ruby Extension Q V' + Q::VERSION)

# load specifiation from gemspec and create
# a task for every extension file in
# executables.
spec = Gem::Specification.load('Q.gemspec')
spec.executables.each do |f|
  Rake::ExtensionTask.new('Q', spec) do |ext|
    # extension file is *.so, so we need
    # to chop the extension to get the name
    ext.name    = f.gsub(/\.so$/,'')
    ext.tmp_dir = 'tmp'
    ext.lib_dir = 'bin'
  end
end

# clean environment by removing old binaries
override_task :clean do
  puts Q::Console.txNote('cleaning...')
  clear_tmp
  begin
    Rake::Task["clean:original"].invoke
    puts Q::Console.txConfirm('...cleaned!')
  rescue
    puts Q::Console.txAlert('could not clean: ' + $!.to_s)
    exit
  end
end

# initialize directory structure
task :init do
  FileCheckCreateDirectory($myDir + '/bin')
  FileCheckCreateDirectory($myDir + '/tmp')
end

# compile module and install to lib
override_task :compile do
  puts Q::Console.txNote('compiling...')
  begin
    Rake::Task["compile:original"].invoke
    puts Q::Console.txConfirm('...compiled!')
  rescue Exception
    puts Q::Console.txAlert('could not compile: ' + $!.to_s)
    exit
  ensure
    clear_tmp
    puts
  end
end

# show commands
task :help do
  show_help
end

# build module and install
task :build => [:init, :clean, :compile]

Bundler::GemHelper.install_tasks

# remove any temporary files
def clear_tmp
  FileUtils.rm_rf(Dir.glob($myDir + '/tmp/*'))
end

# display help screen
def show_help
  Q::Console.out(Q::Console.txCode('build') + '      performs init, clean and compile.')
  Q::Console.out(Q::Console.txCode('clean') + '      removes any old binaries from temp-dir.')
  Q::Console.out(Q::Console.txCode('compile') + '    compiles binaries.')
  Q::Console.out(Q::Console.txCode('help') + '       enlists rake-commands (this page).')
  Q::Console.out(Q::Console.txCode('init') + '       creates gems directory structure.')
  puts
end

Answer 1

Ok, this error-message was really of little use at all…

The problem was that Gem::Specification.executables was empty due to a not matching regex in gemspec. As I iterate though it (see Rakefile), there was no extensiontask build, hence the misleading error.