[PATCH] org.el: Fix newline at eob in org-insert-heading

[Leo Vivier <zaephon@gmail.com>]

* lisp/org.el (org-insert-heading): Check if narrowed before inserting
newline at eob

When narrowed into an org-buffer (e.g. when capturing), adding a new
heading with C-<return> or M-<return> on the last line of a
buffer (i.e. that not without a newline at the end) would result in
the insertion of a newline at the bottom of the narrowed capture
buffer.

- C-<return>: `org-insert-heading-respect-content'
- M-<return>: `org-meta-return'

Both functions use `org-insert-heading' in their definitions.

The problem is due to `eobp' returning t when point is on the last
character of the narrowed buffer (as explained in its docstring).
Since those `eobp' predicates in `org-insert-heading' are probably
there to ensure a newline at the end of the *file*, checking whether
the buffer is *narrowed* (with `buffer-narrowed-p') prior to inserting
the newline fixes the problem.

TINYCHANGE
---
 lisp/org.el | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/lisp/org.el b/lisp/org.el
index e2258749b..7e74c2199 100644
--- a/lisp/org.el
+++ b/lisp/org.el
@@ -7542,7 +7542,9 @@ unconditionally."
       (unless (and blank? (org-previous-line-empty-p))
 	(org-N-empty-lines-before-current (if blank? 1 0)))
       (insert stars " ")
-      (when (eobp) (save-excursion (insert "\n")))
+      (when (and (eobp)
+                 (not (buffer-narrowed-p)))
+        (save-excursion (insert "\n")))
       ;; When INVISIBLE-OK is non-nil, ensure newly created headline
       ;; is visible.
       (unless invisible-ok
@@ -7570,12 +7572,16 @@ unconditionally."
 	       (when blank? (insert "\n"))
 	       (insert "\n" stars " ")
 	       (when (org-string-nw-p split) (insert split))
-	       (when (eobp) (save-excursion (insert "\n")))))
+	       (when (and (eobp)
+                          (not (buffer-narrowed-p)))
+                 (save-excursion (insert "\n")))))
 	    (t
 	     (end-of-line)
 	     (when blank? (insert "\n"))
 	     (insert "\n" stars " ")
-	     (when (eobp) (save-excursion (insert "\n"))))))
+	     (when (and (eobp)
+                        (not (buffer-narrowed-p)))
+               (save-excursion (insert "\n"))))))
      ;; On regular text, turn line into a headline or split, if
      ;; appropriate.
      ((bolp)
-- 
2.20.1