gexp: 'lower-object' raises an exception when passed an invalid object.

* guix/gexp.scm (&gexp-error, &gexp-input-error): New error conditions.
(lower-object): Raise &gexp-input-error when 'lookup-compiler' returns #f.
* tests/gexp.scm ("lower-object & gexp-input-error?"): New test.
* guix/ui.scm (call-with-error-handling): Add case for 'gexp-input-error?'.

1 files changed, 7 insertions, 0 deletions

diff --git a/tests/gexp.scm b/tests/gexp.scm
index b3f7323984..41a53ae5a4 100644
--- a/tests/gexp.scm
+++ b/tests/gexp.scm
@@ -946,6 +946,13 @@
                      (string=? (readlink (string-append comp "/text"))
                                text)))))))
 
+(test-assert "lower-object & gexp-input-error?"
+  (guard (c ((gexp-input-error? c)
+             (gexp-error-invalid-input c)))
+    (run-with-store %store
+      (lower-object (current-module))
+      #:guile-for-build (%guile-for-build))))
+
 (test-assert "printer"
   (string-match "^#<gexp \\(string-append .*#<package coreutils.*\
  \"/bin/uname\"\\) [[:xdigit:]]+>$"