Fix issue with mml-preview from outside Gnus

* lisp/gnus/gnus-art.el (gnus-mime-display-alternative): Be more
resilient when running from outside Gnus.

diff --git a/lisp/gnus/gnus-art.el b/lisp/gnus/gnus-art.el
index b989446792bd4df5f78bbff392f6f4ea5d4e3f44..fb0295d07030de3a19d65e20b64e6f1bc3cb30c6 100644 (file)
--- a/lisp/gnus/gnus-art.el
+++ b/lisp/gnus/gnus-art.el
@@ -6238,8 +6238,9 @@ If nil, don't show those extra buttons."
              (gnus-display-mime preferred)
            (let ((mail-parse-charset gnus-newsgroup-charset)
                  (mail-parse-ignored-charsets
-                  (with-current-buffer gnus-summary-buffer
-                    gnus-newsgroup-ignored-charsets)))
+                   (and (buffer-live-p gnus-summary-buffer)
+                       (with-current-buffer gnus-summary-buffer
+                         gnus-newsgroup-ignored-charsets))))
              (gnus-bind-mm-vars (mm-display-part preferred))
              ;; Do highlighting.
              (save-excursion