file-systems: 'uuid' raises a syntax error for invalid UUIDs.

* gnu/system/file-systems.scm (uuid): Call 'syntax-violation' when
  'string->uuid' returns #f.
* tests/file-systems.scm ("uuid, syntax error"): New test.

1 files changed, 4 insertions, 2 deletions

diff --git a/gnu/system/file-systems.scm b/gnu/system/file-systems.scm
index ece8fb41e6..0f3e6fbcaa 100644
--- a/gnu/system/file-systems.scm
+++ b/gnu/system/file-systems.scm
@@ -153,8 +153,10 @@ UUID representation."
       ((_ str)
        (string? (syntax->datum #'str))
        ;; A literal string: do the conversion at expansion time.
-       (with-syntax ((bv (string->uuid (syntax->datum #'str))))
-         #''bv))
+       (let ((bv (string->uuid (syntax->datum #'str))))
+         (unless bv
+           (syntax-violation 'uuid "invalid UUID" s))
+         (datum->syntax #'str bv)))
       ((_ str)
        #'(string->uuid str)))))