refresh: Distinguish between "no updater" and "failing updater".

Previously, something like "guix refresh texmacs" would report "no
updater".  Now, it reports that the 'gnu-ftp' updater failed to list
releases.

* guix/upstream.scm (lookup-updater): Use 'find' instead of 'any' to
return the <upstream-updater>.
(package-latest-release): Adjust accordingly.
* guix/scripts/refresh.scm (check-for-package-update): When
'package-latest-release' returns #f, distinguish between "no updater"
and "failing updater".

1 files changed, 6 insertions, 6 deletions

diff --git a/guix/upstream.scm b/guix/upstream.scm
index d4f9c5bb45..aa47dab4b4 100644
--- a/guix/upstream.scm
+++ b/guix/upstream.scm
@@ -245,18 +245,18 @@ correspond to the same version."
 (define (lookup-updater package updaters)
   "Return an updater among UPDATERS that matches PACKAGE, or #f if none of
 them matches."
-  (any (match-lambda
-         (($ <upstream-updater> name description pred latest)
-          (and (pred package) latest)))
-       updaters))
+  (find (match-lambda
+          (($ <upstream-updater> name description pred latest)
+           (pred package)))
+        updaters))
 
 (define (package-latest-release package updaters)
   "Return an upstream source to update PACKAGE, a <package> object, or #f if
 none of UPDATERS matches PACKAGE.  It is the caller's responsibility to ensure
 that the returned source is newer than the current one."
   (match (lookup-updater package updaters)
-    ((? procedure? latest-release)
-     (latest-release package))
+    ((? upstream-updater? updater)
+     ((upstream-updater-latest updater) package))
     (_ #f)))
 
 (define (package-latest-release* package updaters)