[bug#31633] [PATCH 2/7] pack: Use 'with-extensions' when referring to (guix docker).

["Ludovic Courtès" <ludo@gnu.org>]

* guix/docker.scm: Use module (json) the normal way.
* guix/scripts/pack.scm (docker-image)[build]: Wrap in
'with-extensions'.
---
 guix/docker.scm       |  6 ++----
 guix/scripts/pack.scm | 37 +++++++++++++++++--------------------
 2 files changed, 19 insertions(+), 24 deletions(-)

diff --git a/guix/docker.scm b/guix/docker.scm
index a75534c33..b86990159 100644
--- a/guix/docker.scm
+++ b/guix/docker.scm
@@ -1,6 +1,6 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2017 Ricardo Wurmus <rekado@elephly.net>
-;;; Copyright © 2017 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2017, 2018 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2018 Chris Marusich <cmmarusich@gmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
@@ -26,6 +26,7 @@
                           delete-file-recursively
                           with-directory-excursion
                           invoke))
+  #:use-module (json)                             ;guile-json
   #:use-module (srfi srfi-19)
   #:use-module (srfi srfi-26)
   #:use-module ((texinfo string-utils)
@@ -34,9 +35,6 @@
   #:use-module (ice-9 match)
   #:export (build-docker-image))
 
-;; Load Guile-JSON at run time to simplify the job of 'imported-modules' & co.
-(module-use! (current-module) (resolve-interface '(json)))
-
 ;; Generate a 256-bit identifier in hexadecimal encoding for the Docker image.
 (define docker-id
   (compose bytevector->base16-string sha256 string->utf8))
diff --git a/guix/scripts/pack.scm b/guix/scripts/pack.scm
index 1e84459e7..f5e247ed7 100644
--- a/guix/scripts/pack.scm
+++ b/guix/scripts/pack.scm
@@ -256,28 +256,25 @@ the image."
         guile-json))
 
   (define build
-    (with-imported-modules `(,@(source-module-closure '((guix docker))
-                                                      #:select? not-config?)
-                             (guix build store-copy)
-                             ((guix config) => ,config))
-      #~(begin
-          ;; Guile-JSON is required by (guix docker).
-          (add-to-load-path
-           (string-append #+json "/share/guile/site/"
-                          (effective-version)))
+    ;; Guile-JSON is required by (guix docker).
+    (with-extensions (list json)
+      (with-imported-modules `(,@(source-module-closure '((guix docker))
+                                                        #:select? not-config?)
+                               (guix build store-copy)
+                               ((guix config) => ,config))
+        #~(begin
+            (use-modules (guix docker) (srfi srfi-19) (guix build store-copy))
 
-          (use-modules (guix docker) (srfi srfi-19) (guix build store-copy))
+            (setenv "PATH" (string-append #$tar "/bin"))
 
-          (setenv "PATH" (string-append #$tar "/bin"))
-
-          (build-docker-image #$output
-                              (call-with-input-file "profile"
-                                read-reference-graph)
-                              #$profile
-                              #:system (or #$target (utsname:machine (uname)))
-                              #:symlinks '#$symlinks
-                              #:compressor '#$(compressor-command compressor)
-                              #:creation-time (make-time time-utc 0 1)))))
+            (build-docker-image #$output
+                                (call-with-input-file "profile"
+                                  read-reference-graph)
+                                #$profile
+                                #:system (or #$target (utsname:machine (uname)))
+                                #:symlinks '#$symlinks
+                                #:compressor '#$(compressor-command compressor)
+                                #:creation-time (make-time time-utc 0 1))))))
 
   (gexp->derivation (string-append name ".tar"
                                    (compressor-extension compressor))
-- 
2.17.0