175/197: gurses: Don't crash if asked for an item by an invalid index.

[Danny Milosavljevic]

dannym pushed a commit to branch wip-installer-2
in repository guix.

commit 300f5cfeee06fe6fcf63ac752feab996dc412680
Author: John Darrington <address@hidden>
Date:   Tue Feb 7 12:10:13 2017 +0100

    gurses: Don't crash if asked for an item by an invalid index.
    
    * gurses/menu.scm (menu-get-current-item): Return #f if the index is
    out of range.
---
 gurses/menu.scm | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/gurses/menu.scm b/gurses/menu.scm
index d1d7954..36f5b42 100644
--- a/gurses/menu.scm
+++ b/gurses/menu.scm
@@ -64,7 +64,9 @@
 
 (define (menu-get-current-item menu)
   (let ((idx (menu-current-item menu)))
-    (list-ref (menu-items menu) idx)))
+    (if (>= idx (length (menu-items menu)))
+        #f
+        (list-ref (menu-items menu) idx))))
 
 (define (menu-scroll-down menu step)
   (let ((limit (- (length (menu-items menu))