Publish failed using Ant publisher - duplicate entry

I got so frustrated this week with the eclipse + maven + glasfish combo.
It kept on refusing to publish my web project to glassfish with some lame excuse:

Publish failed using Ant publisher
  unable to assemble module
  duplicate entry: some.file

In any case I figured out a workaround (lucky guess):
Right-click on your project -> Maven -> Disable Workspace Resolution

Voi la. I can work again and debug my web apps.