whitespace-mode ignores whitespace-line-column

Question

In ~/.emacs I've globally enabled whitespace-mode:

(require 'whitespace)
(setq whitespace-style '(face empty tabs lines-tail trailing))
(global-whitespace-mode t)

Example buffer content:

-*- fill-column: 100; whitespace-line-column: nil -*-
Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut
labore et dolore magna aliquyam erat, sed diam voluptua.

According to documentation for whitespace-line-column: If nil, the `fill-column' variable value is used. However, that doesn't happen. In the buffer with the above sample content, highlight starts at column 80 (default value):

What I already tried, to no avail:

• Enabled whitespace-mode for that buffer explicitly.

• Buffer local: whitespace-line-column: 100

• In ~/.emacs: whitespace-line-column: nil, whitespace-line-column: 100

Version: GNU Emacs 24.4.1 (i686-pc-mingw32) of 2014-10-24 on LEG570

How can I specify line length for whitespace-mode for an individual buffer?

Answer 1

First off, since you didn't mention it: Using the same version of Emacs (24.4.1), the behavior you describe can be reproduced in emacs -Q.

Secondly, what you are doing should work (AFAICT). It seems that turning on whitespace-mode globally (or even in a mode hook) before visiting a file with a custom whitespace-line-column is what's causing the problem. You might want to consider reporting the issue to the Emacs devs via M-x report-emacs-bug.

Finally, you can get the behavior you want by doing the following:

1. Change your config to

   (require 'whitespace)
   (setq whitespace-style '(face empty tabs lines-tail trailing))
   (add-hook 'hack-local-variables-hook 'whitespace-mode)
   

2. Change headers of any files that should use a custom whitespace-line-column to

   -*- whitespace-line-column: 100; -*-