import: go: Improve error handling.

* guix/import/go.scm (go-module->guix-package*): Handle errors, remove
memoize.
(go-module-recursive-import): Remove 'guard', add memoize.
* guix/scripts/import/go.scm (guix-import-go): Adjust.
* tests/go.scm: Adjust.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

guix/import/go.scm

@@ -6,6 +6,7 @@
 ;;; Copyright © 2021 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2021 Xinglu Chen <public@yoctocell.xyz>
 ;;; Copyright © 2021 Sarah Morgensen <iskarian@mgsn.dev>
+;;; Copyright © 2021 Simon Tournier <zimon.toutoune@gmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -63,6 +64,7 @@
   #:use-module (web uri)
 
   #:export (go-module->guix-package
+            go-module->guix-package*
             go-module-recursive-import))
 
 ;;; Commentary:
@@ -646,7 +648,28 @@ hint: use one of the following available versions ~a\n"
          dependencies+versions
          dependencies))))
 
-(define go-module->guix-package* (memoize go-module->guix-package))
+(define go-module->guix-package*
+  (lambda args
+    ;; Disable output buffering so that the following warning gets printed
+    ;; consistently.
+    (setvbuf (current-error-port) 'none)
+    (let ((package-name (match args ((name _ ...) name))))
+      (guard (c ((http-get-error? c)
+                 (warning (G_ "Failed to import package ~s.
+reason: ~s could not be fetched: HTTP error ~a (~s).
+This package and its dependencies won't be imported.~%")
+                          package-name
+                          (uri->string (http-get-error-uri c))
+                          (http-get-error-code c)
+                          (http-get-error-reason c))
+                 (values #f '()))
+                (else
+                 (warning (G_ "Failed to import package ~s.
+reason: ~s.~%")
+                          package-name
+                          (exception-args c))
+                 (values #f '())))
+        (apply go-module->guix-package args)))))
 
 (define* (go-module-recursive-import package-name
                                      #:key (goproxy "https://proxy.golang.org")
@@ -656,19 +679,8 @@ hint: use one of the following available versions ~a\n"
   (recursive-import
    package-name
    #:repo->guix-package
+   (memoize
     (lambda* (name #:key version repo)
-     ;; Disable output buffering so that the following warning gets printed
-     ;; consistently.
-     (setvbuf (current-error-port) 'none)
-     (guard (c ((http-get-error? c)
-                (warning (G_ "Failed to import package ~s.
-reason: ~s could not be fetched: HTTP error ~a (~s).
-This package and its dependencies won't be imported.~%")
-                         name
-                         (uri->string (http-get-error-uri c))
-                         (http-get-error-code c)
-                         (http-get-error-reason c))
-                (values #f '())))
       (receive (package-sexp dependencies)
           (go-module->guix-package* name #:goproxy goproxy
                                     #:version version

guix/scripts/import/go.scm

@@ -112,10 +112,10 @@ that are not yet in Guix"))
                (map package->definition*
                     (apply go-module-recursive-import arguments))
                ;; Single import.
-               (let ((sexp (apply go-module->guix-package arguments)))
+               (let ((sexp (apply go-module->guix-package* arguments)))
                  (unless sexp
-                   (leave (G_ "failed to download meta-data for module '~a'~%")
+                   (leave (G_ "failed to download meta-data for module '~a'.~%")
-                          module-name))
+                          name))
                  (package->definition* sexp))))))
       (()
        (leave (G_ "too few arguments~%")))

tests/go.scm

@@ -410,6 +410,6 @@ package.")
                               (nix-base32-string->bytevector
                                "0sjjj9z1dhilhpc8pq4154czrb79z9cm044jvn75kxcjv6v5l2m5")
                               #f)))
-                 (go-module->guix-package "github.com/go-check/check")))))))
+                 (go-module->guix-package* "github.com/go-check/check")))))))
 
 (test-end "go")