How Grunt task file rename works

README.md

• If the prod task includes a clean at the end of the list of tasks, running it consecutively will cause it to fail to retrieve the app's controllers (and any other compiled files specified in the include option of the requirejs task.
• The reasoning is that the rename function gets run before any tasks execute, so it actually won't work if run solo (by itself) and will seem to work if a previous build was generated (such as a dev build or any tasks that do compilation).
• Thus, the task will work if run after a test task because the compiled assets exist before entering the prod task.
• This can be resolved by separating the module bundling from compilation or running them as separate shell commands.
• There doesn't seem to be an obvious autonomous way to run this under a single task grouping, given that the include requires compiled assets (such as controllers in our case).

Gruntfile.coffee

# Taken from https://github.com/naganowl/chaplin-mocha-grunt/blob/master/Gruntfile.coffee
module.exports = (grunt) ->
  'use strict'

  # For use as rename method in copy:assets.
  # Used to flatten the directory and place matched file in dest.
  flattenFile = (dest, src) ->
    if src.indexOf(@path) is 0
      dest + src.slice @path.length
    else
      dest + src

  # Load all grunt tasks matching the `grunt-*` pattern
  require('load-grunt-tasks')(grunt)

  grunt.initConfig
    pkg: grunt.file.readJSON 'package.json'

    clean:
      public:
        src: 'public/*'

    handlebars:
      compile:
        options:
          amd: yes
          namespace: 'Handlebars.templates'
          processName: (file) ->
            file.replace('app/views/templates/', '').replace '.hbs', ''
        files:
          'public/src/views/templates.js': 'app/views/templates/*.hbs'

    stylus:
      compile:
        options:
          compress: no
          'include css': yes
          urlfunc: 'embedurl'
          linenos: yes
          define:
            '$version': '<%= pkg.version %>'
        files:
          'public/stylesheets/application.css': [
            'app/views/styles/**/*.styl'
            '!app/views/styles/retina.styl'
            'app/views/styles/retina.styl'
          ]

    coffee:
      compile:
        expand: yes
        cwd: 'app/'
        src: ['*.coffee', '**/*.coffee']
        dest: 'public/src/'
        ext: '.js'
      # For Mocha tests in browser.
      test:
        expand: yes
        cwd: 'test/'
        src: ['*.coffee', '**/*.coffee']
        dest: 'public/src/test'
        ext: '.js'

    # Docs: https://github.com/jrburke/r.js/blob/master/build/example.build.js
    requirejs:
      compile:
        options:
          baseUrl: 'public/src'
          mainConfigFile: 'public/src/config.js'

          findNestedDependencies: yes
          name: "almond"

          # Handlebars templates won't load correctly with this enabled.
          wrap: no

          out: 'public/javascripts/application.min.js'
          include:['initialize'].concat(grunt.util.
            _(grunt.file.expandMapping(['controllers/*controller.js'], ''
              cwd: 'public/src/'
              rename: (base, path) ->
                path.replace /\.js$/, ''
            )).pluck 'dest')
          optimize: 'none'

          generateSourceMaps: yes
          # Do not preserve any license comments when working with source
          # maps.  These options are incompatible.
          preserveLicenseComments: no
          waitSeconds: 7

    copy:
      main:
        src: 'index.html'
        dest: 'public/index.html'
      test:
        src: [
          'test/index.html'
          'vendor/**/mocha.css'
          'node_modules/grunt-blanket-mocha/**/support/*.js'
        ]
        dest: 'public/'
      assets:
        # `path` property is needed for the rename method.
        files: [
          # Fonts, images, etc.
          expand: yes
          src: 'app/assets/**'
          dest: 'public/'
          path: 'app/assets'
          rename: flattenFile
        ,
          # Fonts, images, etc.
          expand: yes
          src: 'vendor/bower/bootstrap/fonts/**'
          dest: 'public/fonts/'
          path: 'vendor/bower/bootstrap/fonts'
          rename: flattenFile
        ,
          # Vendor source files.
          src: [
            'vendor/**/*.js'
            '!vendor/**/{doc,example,lang,test}*/**'
          ]
          dest: 'public/'
        ]

    concat:
      # Stylus doesn't concat well with Bootstrap.
      css:
        src: [
          'vendor/bower/bootstrap/dist/css/bootstrap.css'
          'public/stylesheets/application.css'
        ]
        dest: 'public/stylesheets/application.css'

    cssmin:
      compile:
        options:
          keepSpecialComments: 0
        src: [
          'vendor/bower/bootstrap/dist/css/bootstrap.css'
          'public/stylesheets/application.css'
        ]
        dest: 'public/stylesheets/application.min.css'

    blanket_mocha:
      options:
        threshold : 50
        globalThreshold : 65
        log : yes
        logErrors: yes
        moduleThreshold : 60
        modulePattern : "./src/(.*?)/"
      ci:
        src: 'public/test/index.html'
        dest: 'test-results.xml'
        options:
          reporter: 'XUnit'
      test:
        src: 'public/test/index.html'

    coffeelint:
      source: ['{app,test}/**/*.coffee', 'Gruntfile.coffee']
      options:
        arrow_spacing: level: 'warn'
        cyclomatic_complexity: level: 'warn'
        max_line_length: level: 'warn'
        no_backticks: level: 'warn'
        no_empty_param_list: level: 'warn'
        no_stand_alone_at: level: 'warn'

    shell:
      options:
        failOnError: yes
      specs:
        command: 'find test -regex ".*-test\.coffee" > public/testSpecs.txt'

    concurrent:
      pipe:
        tasks: ['server', 'watch']
        options:
          logConcurrentOutput: yes

    server:
      options:
        host: '127.0.0.1'
        port: 8000

      release:
        options:
          prefix: 'public/'

    # Only run tasks on modified files.
    watch:
      options:
        spawn: no
        interrupt: yes
        dateFormat: (time) ->
          grunt.log
            .writeln("Compiled in #{time}ms @ #{(new Date).toString()} 💪\n")

      stylus:
        files: 'app/views/styles/**/*.styl'
        tasks: ['newer:stylus', 'concat:css']

      coffee_hbs:
        files: ['{app,test}/**/*.coffee', 'app/views/templates/**/*.hbs']
        tasks: [
          'newer:handlebars'
          'newer:coffee'
          'coffeelint'
          'blanket_mocha:test'
        ]

      lint:
        files: 'Gruntfile.coffee'
        tasks: 'coffeelint'

      main:
        files: 'index.html'
        tasks: 'copy:main'

      test:
        files: 'test/index.html'
        tasks: 'copy:test'


  # Create aliased tasks.
  grunt.registerTask('default', ['build', 'coffeelint', 'test', 'concurrent'])
  grunt.registerTask('test', ['blanket_mocha:test'])
  grunt.registerTask('test:ci', ['compile', 'copy', 'blanket_mocha:ci'])

  grunt.registerTask 'compile', [
    'handlebars'
    'coffee'
    'shell:specs'
  ]

  grunt.registerTask 'build', [
    'clean'

    'stylus'
    'compile'

    'concat:css'
    'copy'
  ]

  grunt.registerTask 'prod', [
    'clean'

    'handlebars'
    'stylus'
    'coffee:compile'

    'copy:assets'
    'copy:main'
    'cssmin'

    'requirejs'
  ]