07/09: refresh: Bail out when asked for a nonexistent updater.

[Ludovic Courtès]

civodul pushed a commit to branch master
in repository guix.

commit fba607b12919b254d75b1e7e9223d712fe2ac32c
Author: Ludovic Courtès <address@hidden>
Date:   Mon Dec 7 23:10:02 2015 +0100

    refresh: Bail out when asked for a nonexistent updater.
    
    * guix/scripts/refresh.scm (lookup-updater): Call 'leave' when 'find'
    returns #f.
---
 guix/scripts/refresh.scm |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/guix/scripts/refresh.scm b/guix/scripts/refresh.scm
index a94bb22..2341ae6 100644
--- a/guix/scripts/refresh.scm
+++ b/guix/scripts/refresh.scm
@@ -197,9 +197,10 @@ unavailable optional dependencies such as Guile-JSON."
 
 (define (lookup-updater name)
   "Return the updater called NAME."
-  (find (lambda (updater)
-          (eq? name (upstream-updater-name updater)))
-        %updaters))
+  (or (find (lambda (updater)
+              (eq? name (upstream-updater-name updater)))
+            %updaters)
+      (leave (_ "~a: no such updater~%") name)))
 
 (define (list-updaters-and-exit)
   "Display available updaters and exit."