diff --git a/guix/derivations.scm b/guix/derivations.scm
index 5ca516a..eb758b1 100644
--- a/guix/derivations.scm
+++ b/guix/derivations.scm
@@ -701,7 +701,7 @@ derivations where the costs of data transfers would outweigh the benefits."
                                    (derivation->string drv)
                                    (map derivation-input-path
                                         inputs))))
-      (set-file-name drv file))))
+      (pk 'debug-drv (set-file-name drv file)))))
 
 (define* (map-derivation store drv mapping
                          #:key (system (%current-system)))