ruby: unknown encoding name: undecided

I've actually figured out what causes this error, but Googling for it was unsuccessful so I thought I'd write it down here to help out other people. This error pops up when you've got an # -*- coding: undecided -*- comment at the top of one of your files. Emacs added this automatically for me, but re-saving the file caus开发者_开发技巧ed it to be changed to the correct # -*- coding: utf-8 -*-.

This error pops up when you've got an # -*- coding: undecided -*- comment at the top of one of your files. Emacs added this automatically for me, but re-saving the file caused it to be changed to the correct # -*- coding: utf-8 -*-.