Rake FileTask rebuilds despite :intemediate => :phony - ruby-on-rails

Question

Problem
I am trying to use phony tasks in Rake, to prevent forced rebuild of my FileTasks.
(Exerpt from ruby/lib/rake/phony.rb on GitHub)
# Defines a :phony task that you can use as a dependency. This allows
# file-based tasks to use non-file-based tasks as prerequisites
# without forcing them to rebuild.
Despite using the :phony task, my FileTasks still rebuild. I have made an example demonstrating this.
Example Scenario
We need to build final.file from source.file, using an :intermediate task.
It should only rebuild if final.file is out of date with source.file. However, listing :intermediate as a prerequisite, forces a rebuild every time.
Using rake/phony and the :phony task as a prerequisite is supposed to fix that, but doesn't.
Example Code:
require 'rake/phony'
task :default => 'final.file'
file 'final.file' => ['source.file', :intermediate] do |f|
touch f.name
end
# Marked as phony, so should not force FileTask to rebuild
task :intermediate => [:phony] do |t|
puts "#{t.name} task"
end
Problem Demonstation
$ touch source.file # Create the source file
$ rake # Run Rake to build 'final.file'
intermediate task
touch final.file
$ rake # Rake should NOT rebuild, but does. <<<<<<<<
intermediate task
touch final.file
Version
As you can see, I am using a more recent version of Rake than the one which introduced phony tasks (which was 0.9.4), so :phony should work.
$ ruby -v
ruby 2.2.0p0 (2014-12-25 revision 49005) [x86_64-darwin14]
$ rake -V
rake, version 10.4.2

Answer 1

I guess rake/phony is a gem? It's not something built into rake, I don't think, I've never seen it before.
Maybe this one? https://github.com/floere/phony But that seems like it might have nothing to do with what you're talking about, so maybe that's not it, and you are using something else.
Whatever it is you are using, you could try posting an Issue on their github, or otherwise asking them a question if their readme has other preferred methods of receiving questions. It might be a bug in that gem, or maybe that gem doesn't do what you expect.
It's likely few readers here are familiar with that gem, and at any rate don't have the interest to read your lengthy post/question where you paste a huge chunk of source code.
Since we don't know what it is or what it's supposed to do, we don't really have a way to know if it's a bug in that gem or if you're doing it wrong, and while there are lots of people on the internet who enjoy helping out by answering a targetted question on something they are familiar with, there are very few who enjoy going through a vaguely worded "Am I doing something wrong or is it broken?" question that pastes in gigantic swathes of source material, on something they are not familiar with.

Answer 2

I think lib/rake/task.rb has a broken definition of "timestamp" method.
Here is what I think it should be:
def timestamp # on Task
prerequisite_tasks.collect { |pre| pre.timestamp }.max || Time.now
end
I found this information in this page:
http://blog.zenspider.com/blog/2012/01/simulating-phony-in-rake.html
So one hack to fix it is to re-open the Task class and redefine the timestamp method like so:
require 'rake/phony'
task :default => %w[targetA]
file targetA: :test do |t|
sh "touch #{t.name}"
end
task :test do |t|
p t.name
end
task :test => :phony
class Rake::Task
def timestamp
prerequisite_tasks.collect { |pre| pre.timestamp }.max || Time.now
end
end

Answer 3

I guess rake/phony is a gem? It's not something built into rake, I don't think, I've never seen it before.
No, it's part of Rake:
https://github.com/ruby/rake/blob/master/lib/rake/phony.rb
It can be used only for File tasks, as a dependency, so that Rake stops complaining that it doesn't know how to build that dependency.
A basic usage example:
require 'rake/phony'
file "doc.html" => "doc.md"
file "doc.md" => :phony
This is taken from an actual Rakefile I use:
require 'rake/phony'
LIB_ES_SOURCES = FileList['alan_en/StartLib/*.i']
LIB_ES_SOURCES.each do |lib_src|
file 'alan_en/cloak/cloakv3.a3c' => "#{lib_src}"
file lib_src => :phony
end
where I need every *.i in the alan_en/StartLib/ folder to depend on the status of the alan_en/cloak/cloakv3.a3c (a compiled VM file); but then Rake would complain that it didn't know how to build all those .i files, hence the line that creates a File task for each .i file, making it dependent on :phony.
Once you require 'rake/phony' the :phony task is immediately available, and you can assign it as the dependency of any File task. It will never require executing the task since its always mimicking an up to date status, so it won't execute any custom code either (it's what its name indicates: a dummy/phony/fake task).