bug#44115: [PATCH] import: Make failed recursive imports yield an error instead of backtrace.

[Lulu]

* guix/import/utils.scm (recursive-import): Move error handling of recursive 
imports to a single point.
* guix/import/gem.scm (gem->guix-package): Fix the `values' hack and make the 
procedure return #f on failure.
* guix/import/pypi.scm (pypi->guix-package): Fix the condition hack and make 
the procedure return #f on failure.

---
 guix/import/gem.scm   | 2 +-
 guix/import/pypi.scm  | 5 +----
 guix/import/utils.scm | 9 +++++++--
 3 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/guix/import/gem.scm b/guix/import/gem.scm
index 3fe240f36a..c97df149ab 100644
--- a/guix/import/gem.scm
+++ b/guix/import/gem.scm
@@ -143,7 +143,7 @@ VERSION, HASH, HOME-PAGE, DESCRIPTION, DEPENDENCIES, and 
LICENSES."
                                  dependencies
                                  licenses)
                   dependencies-names))
-        (values #f '()))))
+        #f)))
 
 (define (guix-package->gem-name package)
   "Given a PACKAGE built from rubygems.org, return the name of the
diff --git a/guix/import/pypi.scm b/guix/import/pypi.scm
index 15116e349d..9c6a825243 100644
--- a/guix/import/pypi.scm
+++ b/guix/import/pypi.scm
@@ -478,10 +478,7 @@ VERSION, SOURCE-URL, HOME-PAGE, SYNOPSIS, DESCRIPTION, and 
LICENSE."
             (info    (and project (pypi-project-info project))))
        (and project
             (guard (c ((missing-source-error? c)
-                       (let ((package (missing-source-error-package c)))
-                         (leave (G_ "no source release for pypi package ~a 
~a~%")
-                                (project-info-name info)
-                                (project-info-version info)))))
+                       #f))
               (make-pypi-sexp (project-info-name info)
                               (project-info-version info)
                               (and=> (latest-source-release project)
diff --git a/guix/import/utils.scm b/guix/import/utils.scm
index 145515c489..815a05988e 100644
--- a/guix/import/utils.scm
+++ b/guix/import/utils.scm
@@ -36,6 +36,7 @@
   #:use-module (guix store)
   #:use-module (guix download)
   #:use-module (guix sets)
+  #:use-module (guix ui)
   #:use-module (gnu packages)
   #:use-module (ice-9 match)
   #:use-module (ice-9 rdelim)
@@ -428,8 +429,12 @@ name corresponding to the upstream name."
     (not (null? (find-packages-by-name (guix-name name)))))
 
   (define (lookup-node name)
-    (receive (package dependencies) (repo->guix-package name repo)
-      (make-node name package dependencies)))
+    (call-with-values (lambda () (repo->guix-package name repo))
+      (match-lambda*
+        ((#f)
+         (leave (G_ "failed to download package '~a' during recursive 
import~%") name))
+        ((package dependencies)
+         (make-node name package dependencies)))))
 
   (map node-package
        (topological-sort (list (lookup-node package-name))
-- 
2.29.1