emacs: help: check for nil key binding

A standard way to unset a key binding is local-unset-key which is equivalent to
  (define-key (current-local-map) key nil)

Currently notmuch-help gives an error and fails if a user has done this.

To fix this we only add a help line if the binding is non-nil.

diff --git a/emacs/notmuch-lib.el b/emacs/notmuch-lib.el
index bc695119b1978b24fd33c3102cc257bbf1aba278..4c615474dd0e012a4216e316dd4bf1f4bef6a573 100644 (file)
--- a/emacs/notmuch-lib.el
+++ b/emacs/notmuch-lib.el
@@ -253,7 +253,7 @@ prefix argument.  PREFIX and TAIL are used internally."
            (setq tail
                  (notmuch-describe-keymap
                   binding ua-keys (notmuch-prefix-key-description key) tail)))
-          (t
+          (binding
            (when (and ua-keys (symbolp binding)
                       (get binding 'notmuch-prefix-doc))
              ;; Documentation for prefixed command