uninitialized constant Rake::Pipeline::ManifestEntry::DateTime - rake

Question

I'm not a ruby person and i'm working on a project with Ember.js and i'm using Rake pipeline for compile my scripts.
# AssetFile
$: << 'lib'
require 'rake-pipeline-web-filters'
output BUILD
input SRC_DIR do
match '**/*.handlebars' do
handlebars :precompile => true
concat 'templates.js'
end
match '**/*.coffee' do
coffee_script
end
end
output JS_DIR
input BUILD_DIR do
match '*.js' do
concat 'app.js'
end
end
when i execute rakep on the console works fine the first time but the second time i get an const_missing error
c:/Ruby193/lib/ruby/1.9.1/rake/ext/module.rb:36:in `const_missing': uninitialized constant Rake::Pipeline::ManifestEntry::DateTime (NameError)
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline/manifest_entry.rb:9:in `from_hash'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline/manifest.rb:24:in `block in read_manifest'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline/manifest.rb:23:in `each'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline/manifest.rb:23:in `read_manifest'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline/project.rb:225:in `last_manifest'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline/filter.rb:219:in `create_file_task'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline/filter.rb:197:in `block (2 levels) in generate_rake_tasks'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline/filter.rb:196:in `each'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline/filter.rb:196:in `block in generate_rake_tasks'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline/filter.rb:194:in `each'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline/filter.rb:194:in `map'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline/filter.rb:194:in `generate_rake_tasks'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline.rb:410:in `block in generate_rake_tasks'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline.rb:407:in `each'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline.rb:407:in `generate_rake_tasks'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline.rb:333:in `setup'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline.rb:308:in `block in invoke'
from <internal:prelude>:10:in `synchronize'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline.rb:305:in `invoke'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline/project.rb:111:in `each'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline/project.rb:111:in `block in invoke'
from <internal:prelude>:10:in `synchronize'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline/project.rb:110:in `invoke'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/lib/rake-pipeline/cli.rb:19:in `build'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.16.0/lib/thor/task.rb:27:in `run'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.16.0/lib/thor/invocation.rb:120:in `invoke_task'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.16.0/lib/thor.rb:275:in `dispatch'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/thor-0.16.0/lib/thor/base.rb:425:in `start'
from c:/Ruby193/lib/ruby/gems/1.9.1/gems/rake-pipeline-0.7.0/bin/rakep:4:in `<top (required)>'
from c:/Ruby193/bin/rakep:23:in `load'
from c:/Ruby193/bin/rakep:23:in `<main>'
the rakep command works fine when i remove the files manually or let pass time
Note:I am also having problems to sort the files to concatenate

Answer 1

I just hit upon the same problem. I'm using rake-pipeline to minify stylesheets for a static site.
What's happening here is that rake-pipeline is trying to parse a datetime using the DateTime class, but since you're not working on a Ruby project, the class isn't available. I guess because rake-pipeline is mostly used in Ruby projects, nobody noticed that this was a problem at the time. I can see that this problem has been fixed on the master branch, but a new gem version hasn't been released yet.
In the meantime, you can add the following code to your Assetfile (before your input and output), which will delete the tmp directory before your filters run. This is only a temporary fix as it means that your inputs will be filtered every time, regardless of whether they've changed, but it does negate the need for any dodgy datetime parsing.
require 'fileutils'
FileUtils.rm_rf 'tmp'
Be careful with rm_rf! Make sure it's pointing at your tmp directory and nothing else.
Re: sorting your files, I don't know the specifics of your problem, but you might find this example helpful.