(gud-display-line): Don't crash if BUFFER is nil.

diff --git a/lisp/gud.el b/lisp/gud.el
index cbbd4aeb2d923230f4f32e8f173a891161484af1..281ceb50573a0f0b7796d119d762ab5d02c4c238 100644 (file)
--- a/lisp/gud.el
+++ b/lisp/gud.el
@@ -1355,22 +1355,24 @@ Obeying it means displaying in another window the specified file and line."
            (or (eq (current-buffer) gud-comint-buffer)
                (set-buffer gud-comint-buffer))
            (gud-find-file true-file)))
-        (window (display-buffer buffer))
+        (window (and buffer (display-buffer buffer)))
         (pos))
-    (save-excursion
-      (set-buffer buffer)
-      (save-restriction
-       (widen)
-       (goto-line line)
-       (setq pos (point))
-       (setq overlay-arrow-string "=>")
-       (or overlay-arrow-position
-           (setq overlay-arrow-position (make-marker)))
-       (set-marker overlay-arrow-position (point) (current-buffer)))
-      (cond ((or (< pos (point-min)) (> pos (point-max)))
-            (widen)
-            (goto-char pos))))
-    (set-window-point window overlay-arrow-position)))
+    (if buffer
+       (progn
+         (save-excursion
+           (set-buffer buffer)
+           (save-restriction
+             (widen)
+             (goto-line line)
+             (setq pos (point))
+             (setq overlay-arrow-string "=>")
+             (or overlay-arrow-position
+                 (setq overlay-arrow-position (make-marker)))
+             (set-marker overlay-arrow-position (point) (current-buffer)))
+           (cond ((or (< pos (point-min)) (> pos (point-max)))
+                  (widen)
+                  (goto-char pos))))
+         (set-window-point window overlay-arrow-position)))))
 
 ;;; The gud-call function must do the right thing whether its invoking
 ;;; keystroke is from the GUD buffer itself (via major-mode binding)