'wrong-type-argument stringp nil' Error With org-babel-load-file Function

Question

I'm following the tutorial here to implement my init.el file in org mode. I therefore cleaned out my init.el file and added this only:

(require 'org)
(org-babel-load-file
 (expand-file-name "emacs-init.org"
                   user-emacs-directory))

When I do I get the following error:

Debugger entered--Lisp error: (wrong-type-argument stringp nil)
  expand-file-name(nil)
  load-file(nil)
  org-babel-load-file("/home/tom/.emacs.d/emacs-init.org")
  mapc(org-babel-load-file ("/home/tom/.emacs.d/emacs-init.org"))
  eval-buffer(#<buffer  *load*> nil "/home/tom/.emacs.d/init.el" nil t)  ; Reading at buffer position 1065
  load-with-code-conversion("/home/tom/.emacs.d/init.el" "/home/tom/.emacs.d/init.el" t t)
  load("/home/tom/.emacs.d/init" t t)
  ...
  command-line()
  normal-top-level()

It seems that the expand-file-name function is working, but for some reason nil is being passed to the load-file function. Is that a proper reading of this stack trace? And if so, then why is that happening?

Answer 1

Load the source file that defines org-babel-load-file (*.el, not *.elc). Then M-x debug-on-entry org-babel-load-file. Use d to step through the execution, to see why, given the argument "/home/tom/.emacs.d/emacs-init.org", it ends up trying to load nil and not a file name. You can use c to skip through any steps you are not interested in digging into.

See the Elisp manual, node Function Debugging (and its parent node, Debugger).

Answer 2

Ok, after using Drew's debugging steps I learned that org-babel-load-file basically does the following:

1. Load your emacs-init.org file in org-mode.
2. Strip out all of the emacs-lisp code blocks that contain your emacs config.
3. Put those emacs-lisp code blocks into a file called emacs-init.el.
4. It then executes the code in that file.

My issue was that my emacs-init.org file didn't yet contain any emacs-lisp code blocks so it couldn't create the emacs-init.el file, which is why nil is being passed to load-file.

So here's what I'm doing instead that is working much better.

1. I added the code snippet in my question to the top of my existing init.el file.
2. I then created an emacs-init.org file in the .emacs.d dir.
3. I then moved a couple lines of config from init.el to emacs-init.org.
4. I then start a second emacs process to test everything.

My plan is to move everything in chunks like this.

Answer 3

You must tell your "emacs-init.org" which language is it.

 #+BEGIN_SRC LANGUAGE NAME
.
.
.
#+END_SRC

Example for emacs-lisp

#+BEGIN_SRC emacs-lisp
(tool-bar-mode -1)
(menu-bar-mode -1)
(scroll-bar-mode -1)
#+END_SRC