substitute: 'lookup-narinfos' returns exactly a list of narinfos.

* guix/scripts/substitute.scm (lookup-narinfos): Filter out #f values
  from CACHED, such that the end result is exactly a list of narinfos,
  not interspersed with #f.
* guix/scripts/challenge.scm (discrepancies): Assume REMOTE is a list of
  narinfos.

2 files changed, 5 insertions, 5 deletions

diff --git a/guix/scripts/challenge.scm b/guix/scripts/challenge.scm
index 19a9b061b8a..4a0c865b07f 100644
--- a/guix/scripts/challenge.scm
+++ b/guix/scripts/challenge.scm
@@ -125,10 +125,8 @@ taken since we do not import the archives."
                                               servers))
                        ;; No 'assert-valid-narinfo' on purpose.
                        (narinfos -> (fold (lambda (narinfo vhash)
-                                            (if narinfo
-                                                (vhash-cons (narinfo-path narinfo) narinfo
-                                                            vhash)
-                                                vhash))
+                                            (vhash-cons (narinfo-path narinfo) narinfo
+                                                        vhash))
                                           vlist-null
                                           remote)))
     (return (filter-map (lambda (item local)
diff --git a/guix/scripts/substitute.scm b/guix/scripts/substitute.scm
index 0377bb6abe5..34fee5863f2 100755
--- a/guix/scripts/substitute.scm
+++ b/guix/scripts/substitute.scm
@@ -598,7 +598,9 @@ information is available locally."
                          (let-values (((valid? value)
                                        (cached-narinfo cache path)))
                            (if valid?
-                               (values (cons value cached) missing)
+                               (if value
+                                   (values (cons value cached) missing)
+                                   (values cached missing))
                                (values cached (cons path missing)))))
                        '()
                        '()