Fix infloop in woman-file-name

* lisp/woman.el (woman-file-name): Fix infloop for non-existent
manual page (bug#414).

1 files changed, 4 insertions, 2 deletions

diff --git a/lisp/woman.el b/lisp/woman.el
index d9aa573d27b..0bc992d8f7f 100644
--- a/lisp/woman.el
+++ b/lisp/woman.el
@@ -1274,9 +1274,11 @@ cache to be re-read."
        ;; Complete topic more carefully, i.e. use the completion
        ;; rather than the string entered by the user:
        ((setq files (all-completions topic woman-topic-all-completions))
-        (while (/= (length topic) (length (car files)))
+        (while (and files
+                    (/= (length topic) (length (car files))))
           (setq files (cdr files)))
-        (setq files (woman-file-name-all-completions (car files)))))
+        (when files
+          (setq files (woman-file-name-all-completions (car files))))))
       (cond
        ((null files) nil)               ; no file found for topic.
        ((null (cdr files)) (car (car files))) ; only 1 file for topic.