[PATCH 1/4] emacs: help: check for nil key binding

[Mark Walters]

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 check for a nil binding before adding a help line.
---
 emacs/notmuch.el |   25 +++++++++++++------------
 1 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/emacs/notmuch.el b/emacs/notmuch.el
index 6081245..f98f8cf 100644
--- a/emacs/notmuch.el
+++ b/emacs/notmuch.el
@@ -158,18 +158,19 @@ prefix argument.  PREFIX and TAIL are used internally."
 		  (notmuch-describe-keymap
 		   binding ua-keys (notmuch-prefix-key-description key) tail)))
 	   (t
-	    (when (and ua-keys (symbolp binding)
-		       (get binding 'notmuch-prefix-doc))
-	      ;; Documentation for prefixed command
-	      (let ((ua-desc (key-description ua-keys)))
-		(push (concat ua-desc " " prefix (format-kbd-macro (vector key))
-			      "\t" (get binding 'notmuch-prefix-doc))
-		      tail)))
-	    ;; Documentation for command
-	    (push (concat prefix (format-kbd-macro (vector key)) "\t"
-			  (or (and (symbolp binding) (get binding 'notmuch-doc))
-			      (notmuch-documentation-first-line binding)))
-		  tail))))
+	    (unless (not binding)
+	      (when (and ua-keys (symbolp binding)
+			 (get binding 'notmuch-prefix-doc))
+		;; Documentation for prefixed command
+		(let ((ua-desc (key-description ua-keys)))
+		  (push (concat ua-desc " " prefix (format-kbd-macro (vector key))
+				"\t" (get binding 'notmuch-prefix-doc))
+			tail)))
+	      ;; Documentation for command
+	      (push (concat prefix (format-kbd-macro (vector key)) "\t"
+			    (or (and (symbolp binding) (get binding 'notmuch-doc))
+				(notmuch-documentation-first-line binding)))
+		    tail)))))
    keymap)
   tail)
 
-- 
1.7.9.1