Failed to packaging files in array style?

[skygragon]

debian_package: {
      files: [
        { src: ['src/**/*.js'], dest: '/var/test1/' },
        { src: ['test/**/*.js'], dest: '/var/test2/' }
      ],
  } // <=  debian_package

It failed to packaging:

# grunt debian_package
Running "debian_package:files" (debian_package) task
Warning: Object #<Object> has no method 'indexOf' Use --force to continue.

Aborted due to warnings.

However it will succeed if using single format:

files: { src: ['src/**/*.js'], dest: '/var/test1/' },

Here are the versions I used:

node: 0.10.26
grunt: 0.4.5
grunt-debian-package: 0.1.11

[skygragon]

I figured out: by modifying the example in README to use a sub task, thing goes well.

debian_package: {
  debian: {
      files: [
        { src: ['src/**/*.js'], dest: '/var/test1/' },
        { src: ['test/**/*.js'], dest: '/var/test2/' }
      ],
  }
  } // <=  debian_package