emacs: Fix notmuch-hello to not break when given a very narrow window.

Simply ensure that some subtractions never result in a negative
number, (since emacs complains when asked to create a string with a
negative length).

diff --git a/emacs/notmuch-hello.el b/emacs/notmuch-hello.el
index f8ae332c440ed3b4d9fed18ceb05cd41db6a6e3f..161d6e30d54ded027bc20316c6e793e3939e7fdf 100644 (file)
--- a/emacs/notmuch-hello.el
+++ b/emacs/notmuch-hello.el
@@ -209,11 +209,12 @@ should be. Returns a cons cell `(tags-per-line width)'."
                   ;; after the name.
                   (+ 9 1 widest)))))))
 
-    (cons tags-per-line (/ (- (window-width) notmuch-hello-indent
-                             ;; Count is 9 wide (8 digits plus
-                             ;; space), 1 for the space after the
-                             ;; name.
-                             (* tags-per-line (+ 9 1)))
+    (cons tags-per-line (/ (max 1
+                               (- (window-width) notmuch-hello-indent
+                                  ;; Count is 9 wide (8 digits plus
+                                  ;; space), 1 for the space after the
+                                  ;; name.
+                                  (* tags-per-line (+ 9 1))))
                           tags-per-line))))
 
 (defun notmuch-hello-insert-tags (tag-alist widest target)
@@ -249,7 +250,9 @@ should be. Returns a cons cell `(tags-per-line width)'."
                ;; can just insert `(- widest (length name))' spaces -
                ;; the column separator is included in the button if
                ;; `(equal widest (length name)'.
-               (widget-insert (make-string (- widest (length name)) ? ))))
+               (widget-insert (make-string (max 1
+                                                (- widest (length name)))
+                                           ? ))))
            (setq count (1+ count))
            (if (eq (% count tags-per-line) 0)
                (widget-insert "\n")))