Fold rfc2047 headers correctly when narrowed to header value

* lisp/mail/rfc2047.el (rfc2047-fold-region): Fold headers
correctly if narrowed to the header value.

1 files changed, 13 insertions, 6 deletions

diff --git a/lisp/mail/rfc2047.el b/lisp/mail/rfc2047.el
index e3315120d82..a02201ec323 100644
--- a/lisp/mail/rfc2047.el
+++ b/lisp/mail/rfc2047.el
@@ -732,12 +732,19 @@ Point moves to the end of the region."
   (save-restriction
     (narrow-to-region b e)
     (goto-char (point-min))
-    (let ((break nil)
-          (qword-break nil)
-          (first t)
-          (bol (save-restriction
-                 (widen)
-                 (point-at-bol))))
+    (let* ((break nil)
+           (qword-break nil)
+           (bol (save-restriction
+                  (widen)
+                  (line-beginning-position)))
+           ;; This function is either called with the Header: name in
+           ;; the region or not.  If it's not in the region, then we
+           ;; may already have a space.
+           (first (or (= bol (point))
+                      (save-restriction
+                        (widen)
+                        (save-excursion
+                          (not (re-search-backward "[ \t]" bol t)))))))
       (while (not (eobp))
         (when (and (or break qword-break)
                    (> (- (point) bol) 76))