maint: Switch to Guile-JSON 3.x.

Guile-JSON 3.x is incompatible with Guile-JSON 1.x, which we relied on
until now: it maps JSON dictionaries to alists (instead of hash tables),
and JSON arrays to vectors (instead of lists).  This commit is about
adjusting all the existing code to this new mapping.

* m4/guix.m4 (GUIX_CHECK_GUILE_JSON): New macro.
* configure.ac: Use it.
* doc/guix.texi (Requirements): Mention the Guile-JSON version.
* guix/git-download.scm (git-fetch)[guile-json]: Use GUILE-JSON-3.
* guix/import/cpan.scm (string->license): Expect vectors instead of
lists.
(module->dist-name): Use 'json-fetch' instead of 'json-fetch-alist'.
(cpan-fetch): Likewise.
* guix/import/crate.scm (crate-fetch): Likewise, and call 'vector->list'
for DEPS.
* guix/import/gem.scm (rubygems-fetch): Likewise.
* guix/import/json.scm (json-fetch-alist): Remove.
* guix/import/pypi.scm (pypi-fetch): Use 'json-fetch' instead of
'json-fetch-alist'.
(latest-source-release, latest-wheel-release): Call 'vector->list' on
RELEASES.
* guix/import/stackage.scm (stackage-lts-info-fetch): Use 'json-fetch'
instead of 'json-fetch-alist'.
(lts-package-version): Use 'vector->list'.
* guix/import/utils.scm (hash-table->alist): Remove.
(alist->package): Pass 'vector->list' on the inputs fields, and default
to the empty vector.
* guix/scripts/import/json.scm (guix-import-json): Remove call to
'hash-table->alist'.
* guix/swh.scm (define-json-reader): Expect pair? or null? instead of
hash-table?.
[extract-field]: Use 'assoc-ref' instead of 'hash-ref'.
(json->branches): Use 'map' instead of 'hash-map->list'.
(json->checksums): Likewise.
(json->directory-entries, origin-visits): Call 'vector->list' on the
result of 'json->scm'.
* tests/import-utils.scm ("alist->package with dependencies"): New test.
* gnu/installer.scm (build-compiled-file)[builder]: Use GUILE-JSON-3.
* gnu/installer.scm (installer-program)[installer-builder]: Likewise.
* gnu/installer/locale.scm (iso639->iso639-languages): Use 'assoc-ref'
instead of 'hash-ref', and pass vectors through 'vector->list'.
(iso3166->iso3166-territories): Likewise.
* gnu/system/vm.scm (system-docker-image)[build]: Use GUILE-JSON-3.
* guix/docker.scm (manifest, config): Adjust for Guile-JSON 3.
* guix/scripts/pack.scm (docker-image)[build]: Use GUILE-JSON-3.
* guix/import/github.scm (fetch-releases-or-tags): Update docstring.
(latest-released-version): Use 'assoc-ref' instead of 'hash-ref'.  Pass
the result of 'fetch-releases-or-tags' to 'vector->list'.
* guix/import/launchpad.scm (latest-released-version): Likewise.

22 files changed, 140 insertions, 104 deletions

diff --git a/configure.ac b/configure.ac
index 3918550a79..689b28d984 100644
--- a/configure.ac
+++ b/configure.ac
@@ -119,8 +119,8 @@ if test "x$have_guile_git" != "xyes"; then
 fi
 
 dnl Check for Guile-JSON.
-GUILE_MODULE_AVAILABLE([have_guile_json], [(json)])
-if test "x$have_guile_json" != "xyes"; then
+GUIX_CHECK_GUILE_JSON
+if test "x$guix_cv_have_recent_guile_json" != "xyes"; then
   AC_MSG_ERROR([Guile-JSON is missing; please install it.])
 fi
 
diff --git a/doc/guix.texi b/doc/guix.texi
index f6d9718f59..c2da4ce173 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -750,7 +750,7 @@ or later;
 @c FIXME: Specify a version number once a release has been made.
 @uref{https://gitlab.com/guile-git/guile-git, Guile-Git}, from August
 2017 or later;
-@item @uref{https://savannah.nongnu.org/projects/guile-json/, Guile-JSON};
+@item @uref{https://savannah.nongnu.org/projects/guile-json/, Guile-JSON} 3.x;
 @item @url{https://zlib.net, zlib};
 @item @url{https://www.gnu.org/software/make/, GNU Make}.
 @end itemize
diff --git a/gnu/installer.scm b/gnu/installer.scm
index 1452c4dc7e..15d971dfc4 100644
--- a/gnu/installer.scm
+++ b/gnu/installer.scm
@@ -69,7 +69,7 @@ version of this file."
         (setlocale LC_ALL "en_US.utf8")))
 
   (define builder
-    (with-extensions (list guile-json)
+    (with-extensions (list guile-json-3)
       (with-imported-modules (source-module-closure
                               '((gnu installer locale)))
         #~(begin
@@ -313,7 +313,7 @@ selected keymap."
     ;; packages …), etc. modules.
     (with-extensions (list guile-gcrypt guile-newt
                            guile-parted guile-bytestructures
-                           guile-json guile-git guix)
+                           guile-json-3 guile-git guix)
       (with-imported-modules `(,@(source-module-closure
                                   `(,@modules
                                     (gnu services herd)
diff --git a/gnu/installer/locale.scm b/gnu/installer/locale.scm
index 13f3a1e881..ccffb6d8ef 100644
--- a/gnu/installer/locale.scm
+++ b/gnu/installer/locale.scm
@@ -134,16 +134,18 @@ ISO639-3 and ISO639-5 files."
         (lambda (port-iso639-5)
           (filter-map
            (lambda (hash)
-             (let ((alpha2 (hash-ref hash "alpha_2"))
-                   (alpha3 (hash-ref hash "alpha_3"))
-                   (name   (hash-ref hash "name")))
+             (let ((alpha2 (assoc-ref hash "alpha_2"))
+                   (alpha3 (assoc-ref hash "alpha_3"))
+                   (name   (assoc-ref hash "name")))
                (and (supported-locale? locales alpha2 alpha3)
                     `((alpha2 . ,alpha2)
                       (alpha3 . ,alpha3)
                       (name   . ,name)))))
            (append
-            (hash-ref (json->scm port-iso639-3) "639-3")
-            (hash-ref (json->scm port-iso639-5) "639-5"))))))))
+            (vector->list
+             (assoc-ref (json->scm port-iso639-3) "639-3"))
+            (vector->list
+             (assoc-ref (json->scm port-iso639-5) "639-5")))))))))
 
 (define (language-code->language-name languages language-code)
   "Using LANGUAGES as a list of ISO639 association lists, return the language
@@ -179,10 +181,11 @@ ISO3166 file."
   (call-with-input-file iso3166
     (lambda (port)
       (map (lambda (hash)
-             `((alpha2 . ,(hash-ref hash "alpha_2"))
-               (alpha3 . ,(hash-ref hash "alpha_3"))
-               (name   . ,(hash-ref hash "name"))))
-           (hash-ref (json->scm port) "3166-1")))))
+             `((alpha2 . ,(assoc-ref hash "alpha_2"))
+               (alpha3 . ,(assoc-ref hash "alpha_3"))
+               (name   . ,(assoc-ref hash "name"))))
+           (vector->list
+            (assoc-ref (json->scm port) "3166-1"))))))
 
 (define (territory-code->territory-name territories territory-code)
   "Using TERRITORIES as a list of ISO3166 association lists return the
diff --git a/gnu/system/vm.scm b/gnu/system/vm.scm
index e7f7d8ca51..ac6e4ded92 100644
--- a/gnu/system/vm.scm
+++ b/gnu/system/vm.scm
@@ -514,7 +514,7 @@ system."
         (name  (string-append name ".tar.gz"))
         (graph "system-graph"))
     (define build
-      (with-extensions (cons guile-json           ;for (guix docker)
+      (with-extensions (cons guile-json-3         ;for (guix docker)
                              gcrypt-sqlite3&co)   ;for (guix store database)
         (with-imported-modules `(,@(source-module-closure
                                     '((guix docker)
diff --git a/guix/docker.scm b/guix/docker.scm
index b1bd226fa1..c598a073f6 100644
--- a/guix/docker.scm
+++ b/guix/docker.scm
@@ -62,9 +62,9 @@
 
 (define (manifest path id)
   "Generate a simple image manifest."
-  `(((Config . "config.json")
-     (RepoTags . (,(generate-tag path)))
-     (Layers . (,(string-append id "/layer.tar"))))))
+  `#(((Config . "config.json")
+      (RepoTags . #(,(generate-tag path)))
+      (Layers . #(,(string-append id "/layer.tar"))))))
 
 ;; According to the specifications this is required for backwards
 ;; compatibility.  It duplicates information provided by the manifest.
@@ -81,17 +81,18 @@
   `((architecture . ,arch)
     (comment . "Generated by GNU Guix")
     (created . ,time)
-    (config . ,`((env . ,(map (match-lambda
-                                ((name . value)
-                                 (string-append name "=" value)))
-                              environment))
+    (config . ,`((env . ,(list->vector
+                          (map (match-lambda
+                                 ((name . value)
+                                  (string-append name "=" value)))
+                               environment)))
                  ,@(if entry-point
-                       `((entrypoint . ,entry-point))
+                       `((entrypoint . ,(list->vector entry-point)))
                        '())))
     (container_config . #nil)
     (os . "linux")
     (rootfs . ((type . "layers")
-               (diff_ids . (,(layer-diff-id layer)))))))
+               (diff_ids . #(,(layer-diff-id layer)))))))
 
 (define %tar-determinism-options
   ;; GNU tar options to produce archives deterministically.
diff --git a/guix/git-download.scm b/guix/git-download.scm
index f904d11c25..8f84681d46 100644
--- a/guix/git-download.scm
+++ b/guix/git-download.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2014, 2015, 2016, 2017, 2018 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2014, 2015, 2016, 2017, 2018, 2019 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2017 Mathieu Lirzin <mthl@gnu.org>
 ;;; Copyright © 2017 Christopher Baines <mail@cbaines.net>
 ;;;
@@ -85,7 +85,7 @@ HASH-ALGO (a symbol).  Use NAME as the file name, or a generic name if #f."
     (module-ref (resolve-interface '(gnu packages compression)) 'zlib))
 
   (define guile-json
-    (module-ref (resolve-interface '(gnu packages guile)) 'guile-json))
+    (module-ref (resolve-interface '(gnu packages guile)) 'guile-json-3))
 
   (define gnutls
     (module-ref (resolve-interface '(gnu packages tls)) 'gnutls))
diff --git a/guix/import/cpan.scm b/guix/import/cpan.scm
index d4bea84353..ec86f11743 100644
--- a/guix/import/cpan.scm
+++ b/guix/import/cpan.scm
@@ -76,8 +76,8 @@
    ;; ssleay
    ;; sun
    ("zlib" 'zlib)
-   ((x) (string->license x))
-   ((lst ...) `(list ,@(map string->license lst)))
+   (#(x) (string->license x))
+   (#(lst ...) `(list ,@(map string->license lst)))
    (_ #f)))
 
 (define (module->name module)
@@ -88,10 +88,10 @@
   "Return the base distribution module for a given module.  E.g. the 'ok'
 module is distributed with 'Test::Simple', so (module->dist-name \"ok\") would
 return \"Test-Simple\""
-  (assoc-ref (json-fetch-alist (string-append
-                                "https://fastapi.metacpan.org/v1/module/"
-                                module
-                                "?fields=distribution"))
+  (assoc-ref (json-fetch (string-append
+                          "https://fastapi.metacpan.org/v1/module/"
+                          module
+                          "?fields=distribution"))
              "distribution"))
 
 (define (package->upstream-name package)
@@ -114,7 +114,7 @@ return \"Test-Simple\""
   "Return an alist representation of the CPAN metadata for the perl module MODULE,
 or #f on failure.  MODULE should be e.g. \"Test::Script\""
   ;; This API always returns the latest release of the module.
-  (json-fetch-alist (string-append "https://fastapi.metacpan.org/v1/release/" name)))
+  (json-fetch (string-append "https://fastapi.metacpan.org/v1/release/" name)))
 
 (define (cpan-home name)
   (string-append "https://metacpan.org/release/" name))
diff --git a/guix/import/crate.scm b/guix/import/crate.scm
index 29318aac0e..52c5cb1c30 100644
--- a/guix/import/crate.scm
+++ b/guix/import/crate.scm
@@ -51,7 +51,7 @@
   (define (crate-kind-predicate kind)
     (lambda (dep) (string=? (assoc-ref dep "kind") kind)))
 
-  (and-let* ((crate-json (json-fetch-alist (string-append crate-url crate-name)))
+  (and-let* ((crate-json (json-fetch (string-append crate-url crate-name)))
              (crate (assoc-ref crate-json "crate"))
              (name (assoc-ref crate "name"))
              (version (assoc-ref crate "max_version"))
@@ -63,8 +63,8 @@
                                  string->license)
                           '()))                   ;missing license info
              (path (string-append "/" version "/dependencies"))
-             (deps-json (json-fetch-alist (string-append crate-url name path)))
-             (deps (assoc-ref deps-json "dependencies"))
+             (deps-json (json-fetch (string-append crate-url name path)))
+             (deps (vector->list (assoc-ref deps-json "dependencies")))
              (dep-crates (filter (crate-kind-predicate "normal") deps))
              (dev-dep-crates
               (filter (lambda (dep)
diff --git a/guix/import/gem.scm b/guix/import/gem.scm
index ea576b5e4a..0bf9ff2552 100644
--- a/guix/import/gem.scm
+++ b/guix/import/gem.scm
@@ -40,7 +40,7 @@
 (define (rubygems-fetch name)
   "Return an alist representation of the RubyGems metadata for the package NAME,
 or #f on failure."
-  (json-fetch-alist
+  (json-fetch
    (string-append "https://rubygems.org/api/v1/gems/" name ".json")))
 
 (define (ruby-package-name name)
@@ -130,14 +130,18 @@ VERSION, HASH, HOME-PAGE, DESCRIPTION, DEPENDENCIES, and LICENSES."
                                (assoc-ref package "info")))
                 (home-page    (assoc-ref package "homepage_uri"))
                 (dependencies-names (map (lambda (dep) (assoc-ref dep "name"))
-                                         (assoc-ref* package "dependencies" "runtime")))
+                                         (vector->list
+                                          (assoc-ref* package
+                                                      "dependencies"
+                                                      "runtime"))))
                 (dependencies (map (lambda (dep)
                                      (if (string=? dep "bundler")
                                          "bundler" ; special case, no prefix
                                          (ruby-package-name dep)))
                                    dependencies-names))
                 (licenses     (map string->license
-                                   (assoc-ref package "licenses"))))
+                                   (vector->list
+                                    (assoc-ref package "licenses")))))
            (values (make-gem-sexp name version hash home-page synopsis
                                   description dependencies licenses)
                    dependencies-names)))))
diff --git a/guix/import/github.scm b/guix/import/github.scm
index cdac70420a..fa23fa4c06 100644
--- a/guix/import/github.scm
+++ b/guix/import/github.scm
@@ -1,6 +1,6 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2016 Ben Woodcroft <donttrustben@gmail.com>
-;;; Copyright © 2017, 2018 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2017, 2018, 2019 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2018 Eric Bavier <bavier@member.fsf.org>
 ;;; Copyright © 2019 Arun Isaac <arunisaac@systemreboot.net>
 ;;;
@@ -130,7 +130,7 @@ repository separated by a forward slash, from a string URL of the form
 
 (define (fetch-releases-or-tags url)
   "Fetch the list of \"releases\" or, if it's empty, the list of tags for the
-repository at URL.  Return the corresponding JSON dictionaries (hash tables),
+repository at URL.  Return the corresponding JSON dictionaries (alists),
 or #f if the information could not be retrieved.
 
 We look at both /releases and /tags because the \"release\" feature of GitHub
@@ -172,11 +172,11 @@ empty list."
 'https://github.com/arq5x/bedtools2/archive/v2.24.0.tar.gz' and the name of
 the package e.g. 'bedtools2'.  Return #f if there is no releases"
   (define (pre-release? x)
-    (hash-ref x "prerelease"))
+    (assoc-ref x "prerelease"))
 
   (define (release->version release)
-    (let ((tag (or (hash-ref release "tag_name") ;a "release"
-                   (hash-ref release "name")))   ;a tag
+    (let ((tag (or (assoc-ref release "tag_name") ;a "release"
+                   (assoc-ref release "name")))   ;a tag
           (name-length (string-length package-name)))
       (cond
        ;; some tags include the name of the package e.g. "fdupes-1.51"
@@ -197,7 +197,8 @@ the package e.g. 'bedtools2'.  Return #f if there is no releases"
         tag)
        (else #f))))
 
-  (let* ((json (fetch-releases-or-tags url)))
+  (let* ((json (and=> (fetch-releases-or-tags url)
+                      vector->list)))
     (if (eq? json #f)
         (if (%github-token)
             (error "Error downloading release information through the GitHub
diff --git a/guix/import/json.scm b/guix/import/json.scm
index 81ea5e7b31..8900724dcd 100644
--- a/guix/import/json.scm
+++ b/guix/import/json.scm
@@ -1,7 +1,7 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2014 David Thompson <davet@gnu.org>
 ;;; Copyright © 2015, 2016 Eric Bavier <bavier@member.fsf.org>
-;;; Copyright © 2018 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2018, 2019 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -23,8 +23,7 @@
   #:use-module (guix http-client)
   #:use-module (guix import utils)
   #:use-module (srfi srfi-34)
-  #:export (json-fetch
-            json-fetch-alist))
+  #:export (json-fetch))
 
 (define* (json-fetch url
                      ;; Note: many websites returns 403 if we omit a
@@ -43,9 +42,3 @@ the query."
            (result (json->scm port)))
       (close-port port)
       result)))
-
-(define (json-fetch-alist url)
-  "Return an alist representation of the JSON resource URL, or #f if URL
-returns 403 or 404."
-  (and=> (json-fetch url)
-         hash-table->alist))
diff --git a/guix/import/launchpad.scm b/guix/import/launchpad.scm
index ffd5e9221e..1a15f28077 100644
--- a/guix/import/launchpad.scm
+++ b/guix/import/launchpad.scm
@@ -87,15 +87,16 @@ for example, 'linuxdcpp'. Return #f if there is no releases."
     ;; example, "5.1.0-rc1") are assumed to be pre-releases.
     (not (string-every (char-set-union (char-set #\.)
                                        char-set:digit)
-                       (hash-ref x "version"))))
+                       (assoc-ref x "version"))))
 
-  (hash-ref
+  (assoc-ref
    (last (remove
           pre-release?
-          (hash-ref (json-fetch
-                     (string-append "https://api.launchpad.net/1.0/"
-                                    package-name "/releases"))
-                    "entries")))
+          (vector->list
+           (assoc-ref (json-fetch
+                       (string-append "https://api.launchpad.net/1.0/"
+                                      package-name "/releases"))
+                      "entries"))))
    "version"))
 
 (define (latest-release pkg)
diff --git a/guix/import/pypi.scm b/guix/import/pypi.scm
index ab7a024ee0..9b3d80a02e 100644
--- a/guix/import/pypi.scm
+++ b/guix/import/pypi.scm
@@ -1,7 +1,7 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2014 David Thompson <davet@gnu.org>
 ;;; Copyright © 2015 Cyril Roelandt <tipecaml@gmail.com>
-;;; Copyright © 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2015, 2016, 2017, 2019 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
 ;;; Copyright © 2018 Ricardo Wurmus <rekado@elephly.net>
 ;;; Copyright © 2019 Maxim Cournoyer <maxim.cournoyer@gmail.com>
@@ -56,7 +56,7 @@
 (define (pypi-fetch name)
   "Return an alist representation of the PyPI metadata for the package NAME,
 or #f on failure."
-  (json-fetch-alist (string-append "https://pypi.org/pypi/" name "/json")))
+  (json-fetch (string-append "https://pypi.org/pypi/" name "/json")))
 
 ;; For packages found on PyPI that lack a source distribution.
 (define-condition-type &missing-source-error &error
@@ -69,7 +69,7 @@ or #f on failure."
                               (assoc-ref* pypi-package "info" "version"))))
     (or (find (lambda (release)
                 (string=? "sdist" (assoc-ref release "packagetype")))
-              releases)
+              (vector->list releases))
         (raise (condition (&missing-source-error
                            (package pypi-package)))))))
 
@@ -80,7 +80,7 @@ or #f if there isn't any."
                               (assoc-ref* pypi-package "info" "version"))))
     (or (find (lambda (release)
                 (string=? "bdist_wheel" (assoc-ref release "packagetype")))
-              releases)
+              (vector->list releases))
         #f)))
 
 (define (python->package-name name)
diff --git a/guix/import/stackage.scm b/guix/import/stackage.scm
index 1c1e73a723..194bea633e 100644
--- a/guix/import/stackage.scm
+++ b/guix/import/stackage.scm
@@ -60,7 +60,7 @@
      (let* ((url (if (string=? "" version)
                      (string-append %stackage-url "/lts")
                      (string-append %stackage-url "/lts-" version)))
-            (lts-info (json-fetch-alist url)))
+            (lts-info (json-fetch url)))
        (if lts-info
            (reverse lts-info)
            (leave-with-message "LTS release version not found: ~a" version))))))
@@ -74,7 +74,7 @@
 (define (lts-package-version pkgs-info name)
   "Return the version of the package with upstream NAME included in PKGS-INFO."
   (let ((pkg (find (lambda (pkg) (string=? (stackage-package-name pkg) name))
-                   pkgs-info)))
+                   (vector->list pkgs-info))))
     (stackage-package-version pkg)))
 
 
diff --git a/guix/import/utils.scm b/guix/import/utils.scm
index 84503ab907..2a3b7341fb 100644
--- a/guix/import/utils.scm
+++ b/guix/import/utils.scm
@@ -45,7 +45,6 @@
   #:use-module (srfi srfi-41)
   #:export (factorize-uri
 
-            hash-table->alist
             flatten
             assoc-ref*
 
@@ -100,21 +99,6 @@ of the string VERSION is replaced by the symbol 'version."
                '()
                indices))))))
 
-(define (hash-table->alist table)
-  "Return an alist represenation of TABLE."
-  (map (match-lambda
-        ((key . (lst ...))
-         (cons key
-               (map (lambda (x)
-                      (if (hash-table? x)
-                          (hash-table->alist x)
-                          x))
-                    lst)))
-        ((key . (? hash-table? table))
-         (cons key (hash-table->alist table)))
-        (pair pair))
-       (hash-map->list cons table)))
-
 (define (flatten lst)
   "Return a list that recursively concatenates all sub-lists of LST."
   (fold-right
@@ -330,11 +314,14 @@ the expected fields of an <origin> object."
       (lookup-build-system-by-name
        (string->symbol (assoc-ref meta "build-system"))))
     (native-inputs
-     (specs->package-lists (or (assoc-ref meta "native-inputs") '())))
+     (specs->package-lists
+      (vector->list (or (assoc-ref meta "native-inputs") '#()))))
     (inputs
-     (specs->package-lists (or (assoc-ref meta "inputs") '())))
+     (specs->package-lists
+      (vector->list (or (assoc-ref meta "inputs") '#()))))
     (propagated-inputs
-     (specs->package-lists (or (assoc-ref meta "propagated-inputs") '())))
+     (specs->package-lists
+      (vector->list (or (assoc-ref meta "propagated-inputs") '#()))))
     (home-page
      (assoc-ref meta "home-page"))
     (synopsis
diff --git a/guix/scripts/import/json.scm b/guix/scripts/import/json.scm
index 8771e7b0eb..c9daf65479 100644
--- a/guix/scripts/import/json.scm
+++ b/guix/scripts/import/json.scm
@@ -93,7 +93,7 @@ Import and convert the JSON package definition in PACKAGE-FILE.\n"))
            (let ((json (json-string->scm
                         (with-input-from-file file-name read-string))))
              ;; TODO: also print define-module boilerplate
-             (package->code (alist->package (hash-table->alist json)))))
+             (package->code (alist->package json))))
          (lambda _
            (leave (G_ "invalid JSON in file '~a'~%") file-name))))
       (()
diff --git a/guix/scripts/pack.scm b/guix/scripts/pack.scm
index 01472d9768..fdb98983bf 100644
--- a/guix/scripts/pack.scm
+++ b/guix/scripts/pack.scm
@@ -479,7 +479,7 @@ the image."
 
   (define build
     ;; Guile-JSON and Guile-Gcrypt are required by (guix docker).
-    (with-extensions (list guile-json guile-gcrypt)
+    (with-extensions (list guile-json-3 guile-gcrypt)
       (with-imported-modules `(((guix config) => ,(make-config.scm))
                                ,@(source-module-closure
                                   `((guix docker)
diff --git a/guix/self.scm b/guix/self.scm
index 838ede7690..f03fe01d0c 100644
--- a/guix/self.scm
+++ b/guix/self.scm
@@ -50,7 +50,7 @@
                (module-ref (resolve-interface module) variable))))
     (match-lambda
       ("guile"      (ref '(gnu packages commencement) 'guile-final))
-      ("guile-json" (ref '(gnu packages guile) 'guile-json))
+      ("guile-json" (ref '(gnu packages guile) 'guile-json-3))
       ("guile-ssh"  (ref '(gnu packages ssh)   'guile-ssh))
       ("guile-git"  (ref '(gnu packages guile) 'guile-git))
       ("guile-sqlite3" (ref '(gnu packages guile) 'guile-sqlite3))
diff --git a/guix/swh.scm b/guix/swh.scm
index d692f81806..df2a138f04 100644
--- a/guix/swh.scm
+++ b/guix/swh.scm
@@ -138,16 +138,16 @@ following SPEC, a series of field specifications."
                         (json->scm input))
                        ((string? input)
                         (json-string->scm input))
-                       ((hash-table? input)
+                       ((or (null? input) (pair? input))
                         input))))
       (let-syntax ((extract-field (syntax-rules ()
                                     ((_ table (field key json->value))
-                                     (json->value (hash-ref table key)))
+                                     (json->value (assoc-ref table key)))
                                     ((_ table (field key))
-                                     (hash-ref table key))
+                                     (assoc-ref table key))
                                     ((_ table (field))
-                                     (hash-ref table
-                                               (symbol->string 'field))))))
+                                     (assoc-ref table
+                                                (symbol->string 'field))))))
         (ctor (extract-field table spec) ...)))))
 
 (define-syntax-rule (define-json-mapping rtd ctor pred json->record
@@ -257,12 +257,13 @@ FALSE-IF-404? is true, return #f upon 404 responses."
   (target-url   branch-target-url))
 
 (define (json->branches branches)
-  (hash-map->list (lambda (key value)
-                    (make-branch key
-                                 (string->symbol
-                                  (hash-ref value "target_type"))
-                                 (hash-ref value "target_url")))
-                  branches))
+  (map (match-lambda
+         ((key . value)
+          (make-branch key
+                       (string->symbol
+                        (assoc-ref value "target_type"))
+                       (assoc-ref value "target_url"))))
+       branches))
 
 ;; <https://archive.softwareheritage.org/api/1/release/1f44934fb6e2cefccbecd4fa347025349fa9ff76/>
 (define-json-mapping <release> make-release release?
@@ -292,9 +293,10 @@ FALSE-IF-404? is true, return #f upon 404 responses."
   (license-url   content-license-url "license_url"))
 
 (define (json->checksums checksums)
-  (hash-map->list (lambda (key value)
-                    (cons key (base16-string->bytevector value)))
-                  checksums))
+  (map (match-lambda
+         ((key . value)
+          (cons key (base16-string->bytevector value))))
+       checksums))
 
 ;; <https://archive.softwareheritage.org/api/1/directory/27c69c5d298a43096a53affbf881e7b13f17bdcd/>
 (define-json-mapping <directory-entry> make-directory-entry directory-entry?
@@ -365,14 +367,15 @@ FALSE-IF-404? is true, return #f upon 404 responses."
   json->directory-entries)
 
 (define (json->directory-entries port)
-  (map json->directory-entry (json->scm port)))
+  (map json->directory-entry
+       (vector->list (json->scm port))))
 
 (define (origin-visits origin)
   "Return the list of visits of ORIGIN, a record as returned by
 'lookup-origin'."
   (call (swh-url (origin-visits-url origin))
         (lambda (port)
-          (map json->visit (json->scm port)))))
+          (map json->visit (vector->list (json->scm port))))))
 
 (define (visit-snapshot visit)
   "Return the snapshot corresponding to VISIT."
diff --git a/m4/guix.m4 b/m4/guix.m4
index d0c5ec0f08..716bfb08ec 100644
--- a/m4/guix.m4
+++ b/m4/guix.m4
@@ -174,6 +174,27 @@ AC_DEFUN([GUIX_CHECK_GUILE_SQLITE3], [
      fi])
 ])
 
+dnl GUIX_CHECK_GUILE_JSON
+dnl
+dnl Check whether a recent-enough Guile-JSON is available.
+AC_DEFUN([GUIX_CHECK_GUILE_JSON], [
+  dnl Check whether we're using Guile-JSON 3.x, which uses a JSON-to-Scheme
+  dnl mapping different from that of earlier versions.
+  AC_CACHE_CHECK([whether Guile-JSON is available and recent enough],
+    [guix_cv_have_recent_guile_json],
+    [GUILE_CHECK([retval],
+      [(use-modules (json) (ice-9 match))
+       (match (json-string->scm \"[[] { \\\"a\\\": 42 } []]\")
+         (#(("a" . 42)) #t)
+	 (_ #f))])
+     if test "$retval" = 0; then
+       guix_cv_have_recent_guile_json="yes"
+     else
+       guix_cv_have_recent_guile_json="no"
+     fi])
+])
+
+
 dnl GUIX_TEST_ROOT_DIRECTORY
 AC_DEFUN([GUIX_TEST_ROOT_DIRECTORY], [
   AC_CACHE_CHECK([for unit test root directory],
diff --git a/tests/import-utils.scm b/tests/import-utils.scm
index 5c0c041360..c3ab25d788 100644
--- a/tests/import-utils.scm
+++ b/tests/import-utils.scm
@@ -23,6 +23,7 @@
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix packages)
   #:use-module (guix build-system)
+  #:use-module (gnu packages)
   #:use-module (srfi srfi-64))
 
 (test-begin "import-utils")
@@ -98,4 +99,25 @@
     (or (package-license (alist->package meta))
         'license-is-false)))
 
+(test-equal "alist->package with dependencies"
+  `(("gettext" ,(specification->package "gettext")))
+  (let* ((meta '(("name" . "hello")
+                 ("version" . "2.10")
+                 ("source" . (("method" . "url-fetch")
+                              ("uri"    . "mirror://gnu/hello/hello-2.10.tar.gz")
+                              ("sha256" .
+                               (("base32" .
+                                 "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i")))))
+                 ("build-system" . "gnu")
+                 ("home-page" . "https://gnu.org")
+                 ("synopsis" . "Say hi")
+                 ("description" . "This package says hi.")
+                                                  ;
+                 ;; Note: As with Guile-JSON 3.x, JSON arrays are represented
+                 ;; by vectors.
+                 ("native-inputs" . #("gettext"))
+
+                 ("license" . #f))))
+    (package-native-inputs (alist->package meta))))
+
 (test-end "import-utils")