Problems with longlines-mode

[Sven Joachim]

The minor mode longlines-mode has several problems. First, turning it
on and off again does not turn into a no-op as it should, but changes
several buffer-local variables:

- use-hard-newlines        is set to t
- require-final-new-line   is set to nil (Why?)
- fill-column              is set to its global value

Secondly, it does not work if the buffer is read-only. That may not be
so bad, but at least longlines-mode should fail gracefully and
(barf-if-buffer-read-only) at its very beginning if it cannot handle
read-only buffers. Especially funny is the following scenario:

Visit a file read-only, type M-x longlines-mode (getting a "Buffer is
read-only" error), type C-x C-q to make the buffer read-write and type
M-x longlines-mode again. You will be be rewarded by seeing Emacs
display the whole buffer as a single long line.

I made these observations in

GNU Emacs 22.0.50.1 (i386-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
of 2005-08-20 on debian, modified by Debian.

Regards,

Sven Joachim