(do-auto-fill): Look at 2nd line for fill prefix

even when on the first line.  Don't accept non-whitespace prefix
from the first line.

(do-auto-fill): Ignore the result of fill-context-prefix if it is empty.

diff --git a/lisp/simple.el b/lisp/simple.el
index 9d34a467d965352838c0dc8de006a545a3babd6d..fa442280255ff3f6c8c0e9ecc270d079de97bb22 100644 (file)
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -2331,10 +2331,15 @@ Setting this variable automatically makes it local to the current buffer.")
       ;; Choose a fill-prefix automatically.
       (if (and adaptive-fill-mode
               (or (null fill-prefix) (string= fill-prefix "")))
-         (setq fill-prefix
-               (fill-context-prefix 
-                (save-excursion (backward-paragraph 1) (point))
-                (point))))
+         (let ((prefix
+                (fill-context-prefix
+                 (save-excursion (backward-paragraph 1) (point))
+                 (save-excursion (forward-paragraph 1) (point))
+                 ;; Don't accept a non-whitespace fill prefix
+                 ;; from the first line of a paragraph.
+                 "^[ \t]*$")))
+           (and prefix (not (equal prefix ""))
+                (setq fill-prefix prefix))))
 
       (while (and (not give-up) (> (current-column) fc))
        ;; Determine where to split the line.