This isn't a bug. Grunt no longer supports globbing in dest using that configuration. However, you can use the files array format, like this:

files: [

  {

    expand: true,

    cwd: 'src',

    src: ['*.less'],

    dest: 'assets/css/',

    ext: '.css'

  }

]

Also, if you use a library like Bootstrap and you want to build each LESS file (component) into a separate, individual CSS file, it's not very easy to accomplish out of the box. The reason is that each LESS file would need to have its own @import statements for variables.less and mixins.less (and a couple of others like forms.less and navbar.less, since they are referenced in other files).

To make this really easy, try the Grunt plugin, assemble-less (disclaimer: I'm one of the maintainers of the project, and I'm also on the core team for less.js). assemble-less is a fork of grunt-contrib-less by Tyler Kellen, but it adds some experimental features that will accomplish what you need (if you want stability, please stick with grunt-contrib-less). For example:

// Project configuration.

grunt.initConfig({



  less: {

    // Compile all targeted LESS files individually

    components: {

      options: {

        imports: {

          // Use the new reference directive, e.g.

          // @import (reference) variables.less;

          reference: [

            bootstrap/mixins.less, 

            bootstrap/variables.less 

          ]

        }

      },

      files: [

        {

          expand: true,

          cwd: 'bootstrap/less',

          // Compile each LESS component excluding bootstrap.less, 

          // mixins.less and variables.less 

          src: ['*.less', '!{boot,var,mix}*.less'],

          dest: 'assets/css/',

          ext: '.css'

        }

      ]

    }

  }

  ...

}

The imports feature essentially prepends the specified @import statements onto the source files. The reference option allows you to reference other less files while only outputting styles that are specifically referenced via mixins or :extend. You might need to reference a few more files than shown here, since Bootstrap cross-references styles from other components, like forms.less, buttons.less, etc. (See the Gruntfile in assemble-less for examples.)

So after running the assemble-less task with the configuration in the example above, the assets/css folder would have:

• alerts.css


• badges.css


• breadcrumbs.css


• button-groups.css


• buttons.css


• carousel.css


• close.css


• code.css


• component-animations.css


• dropdowns.css


• forms.css


• glyphicons.css


• grid.css


• input-groups.css


• jumbotron.css


• labels.css


• list-group.css


• media.css


• modals.css


• navbar.css


• navs.css


• normalize.css


• pager.css


• pagination.css


• panels.css


• popovers.css


• print.css


• progress-bars.css


• responsive-utilities.css


• scaffolding.css


• tables.css


• theme.css


• thumbnails.css


• tooltip.css


• type.css


• utilities.css


• wells.css

There are other features that should help you with this, but the imports feature is super powerful since it allows you to add directives directly to the Gruntfile.