bug#29529: next-line-add-newlines shouldn't be respected in next-line-or-history-element

[E. Choroba]

Hi,

I don't like the "end of buffer" errors, so I have switched 
next-line-add-newlines to t. In recent Emacs versions, though, this makes it 
impossible to browse the minibuffer history with cursor arrows: <down> adds a 
newline into the minibufer instead of showing the next history element. M-n 
works correctly, though.

Steps to reproduce (tested in 25.3.1):

emacs -Q
(setq next-line-add-newlines t) C-x C-e
C-x C-f <down>

Solution:

Set the variable to nil locally in next-line-or-history-element.

Patch:

diff -u <(zcat /usr/local/share/emacs/25.3/lisp/simple.el.gz) ~/simple.el
--- /dev/fd/63  2017-12-01 23:45:06.338468797 +0100
+++ /home/choroba/simple.el     2017-12-01 23:45:04.166450109 +0100
@@ -2038,6 +2038,7 @@
   (interactive "^p")
   (or arg (setq arg 1))
   (let* ((old-point (point))
+         (next-line-add-newlines nil)
         ;; Remember the original goal column of possibly multi-line input
         ;; excluding the length of the prompt on the first line.
         (prompt-end (minibuffer-prompt-end))


Cheers,

Ch.