messages: sender: Return unknown sender in the expected format.

diff --git a/mumi/messages.scm b/mumi/messages.scm
index 5a6ca343dd10eceaa536e1713eb5081940984b9c..6354e3c4e81af111ab3b3bdb7533b84e630bde29 100644 (file)
--- a/mumi/messages.scm
+++ b/mumi/messages.scm
@@ -74,7 +74,8 @@ yet.  Return new results alongside cached results."
 
 (define-public (sender message)
   (or (and=> (header message 'from) first)
-      "unknown sender"))
+      '((name . "Unknown sender")
+        (address . "unknown"))))
 
 (define-public sender-email
   (compose extract-email sender))