[bug#33376] [PATCH 1/2] progress: Fix crash because of division by zero.

[Clément Lassieur]

* guix/progress.scm (display-download-progress): Handle the case where SIZE is
null.
---
 guix/progress.scm | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/guix/progress.scm b/guix/progress.scm
index 9da667a02..7a25f11bd 100644
--- a/guix/progress.scm
+++ b/guix/progress.scm
@@ -2,6 +2,7 @@
 ;;; Copyright © 2017 Sou Bunnbu <address@hidden>
 ;;; Copyright © 2015 Steve Sprang <address@hidden>
 ;;; Copyright © 2017, 2018 Ludovic Courtès <address@hidden>
+;;; Copyright © 2018 Clément Lassieur <address@hidden>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -197,7 +198,7 @@ throughput."
   (define elapsed
     (duration->seconds
      (time-difference (current-time time-monotonic) start-time)))
-  (if (number? size)
+  (if (and (number? size) (not (zero? size)))
       (let* ((%  (* 100.0 (/ transferred size)))
              (throughput (/ transferred elapsed))
              (left       (format #f " ~a  ~a" file
-- 
2.19.1