Vim ":source %" command results in Error (E499)

Question

Hello fellow Stack Overflow vim users, I have recently found myself spending a considerable amount of time in my school's Computer Science lab writing code. I've configured vim on countless linux systems and have never encountered this error:

E499: Empty file name for '%' or '#', only works with ":p:h"

This error happens anytime I use % in a command in vim. I've never seen this before, but I will give as much info as I can. Here is my .vimrc:

set nocompatible
filetype off

set rtp+=~/.vim/bundle/Vundle.vim
call vundle#begin()

Plugin 'VundleVim/Vundle.vim'
"Plugin 'scrooloose/nerdtree'
"Plugin 'bling/vim-airline'
"Plugin 'altercation/vim-colors-solarized'

call vundle#end()
filetype plugin indent on

I've commented out those last few plugins to see if they had any correlation with the error, but that didn't seem to help. I used Git to install vim as usual:

git clone https://github.com/VundleVim/Vundle.vim.git ~/.vim/bundle/Vundle.vim

All I did after that was run :PluginInstall to install the plugins, and then tried to use :source %, resulting in the error.

This has really stumped me, and I hope to solve it, as I'd like to use my customized vim setup for this CS class, but I can deal with stock ViM or even Vi, or if it comes to it... nano.

EDIT: Using Ubuntu 15.04

Answer 1

This seems to be related to empty %. You can do two things: pass the filename when invoking vim: vim myscript.vim and then calling :source %, or passing the filename to :source (:source myscript.vim).

EDIT

If you issue :help registers, there is listed that % is a read-only register containing the current filename. So, if you are editing a buffer that doesn't have a filename (not saved), this register is empty and so you get error message.