(rmail-output-body-to-file): Avoid error if message has no subject.

Use and set rmail-default-body-file.

diff --git a/lisp/mail/rmailout.el b/lisp/mail/rmailout.el
index 1834ff5ae26e5a34fba901c0cac70177d7729fa2..7a8bfcf393ee361ab9e24661006ee3c41d8e156c 100644 (file)
--- a/lisp/mail/rmailout.el
+++ b/lisp/mail/rmailout.el
@@ -333,12 +333,18 @@ The optional fourth argument FROM-GNUS is set when called from GNUS."
 FILE-NAME defaults, interactively, from the Subject field of the message."
   (interactive
    (let ((default-file
-          (mail-fetch-field "Subject")))
-     (list (read-file-name
-           "Output message body to file: "
-           (file-name-directory default-file)
-           default-file
-           nil default-file))))
+          (or (mail-fetch-field "Subject")
+              rmail-default-body-file)))
+     (list (setq rmail-default-body-file
+                (read-file-name
+                 "Output message body to file: "
+                 (and default-file (file-name-directory default-file))
+                 default-file
+                 nil default-file)))))
+  (setq file-name
+       (expand-file-name file-name
+                         (and rmail-default-body-file
+                              (file-name-directory rmail-default-body-file))))
   (save-excursion
     (goto-char (point-min))
     (search-forward "\n\n")