Merge remote-tracking branch 'origin/master' into wip-texlive

24 files changed, 502 insertions, 283 deletions

diff --git a/guix/build/cargo-build-system.scm b/guix/build/cargo-build-system.scm
index f38de16cf7..7d363a18a5 100644
--- a/guix/build/cargo-build-system.scm
+++ b/guix/build/cargo-build-system.scm
@@ -2,6 +2,7 @@
 ;;; Copyright © 2016 David Craven <david@craven.ch>
 ;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
 ;;; Copyright © 2019 Ivan Petkov <ivanppetkov@gmail.com>
+;;; Copyright © 2019 Efraim Flashner <efraim@flashner.co.il>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -39,6 +40,21 @@
 ;;
 ;; Code:
 
+;; TODO: Move this to (guix build cargo-utils). Will cause a full rebuild
+;; of all rust compilers.
+
+(define (generate-all-checksums dir-name)
+  (for-each
+    (lambda (filename)
+      (let* ((dir (dirname filename))
+             (checksum-file (string-append dir "/.cargo-checksum.json")))
+        (when (file-exists? checksum-file) (delete-file checksum-file))
+        (display (string-append
+                   "patch-cargo-checksums: generate-checksums for "
+                   dir "\n"))
+        (generate-checksums dir)))
+    (find-files dir-name "Cargo.toml$")))
+
 (define (manifest-targets)
   "Extract all targets from the Cargo.toml manifest"
   (let* ((port (open-input-pipe "cargo read-manifest"))
@@ -94,8 +110,7 @@ Cargo.toml file present at its root."
               ;; so that we can generate any cargo checksums.
               ;; The --strip-components argument is needed to prevent creating
               ;; an extra directory within `crate-dir`.
-              (invoke "tar" "xvf" path "-C" crate-dir "--strip-components" "1")
-              (generate-checksums crate-dir)))))
+              (invoke "tar" "xvf" path "-C" crate-dir "--strip-components" "1")))))
     inputs)
 
   ;; Configure cargo to actually use this new directory.
@@ -121,6 +136,31 @@ directory = '" port)
   (setenv "CC" (string-append (assoc-ref inputs "gcc") "/bin/gcc"))
   #t)
 
+;; The Cargo.lock file tells the build system which crates are required for
+;; building and hardcodes their version and checksum.  In order to build with
+;; the inputs we provide, we need to recreate the file with our inputs.
+(define* (update-cargo-lock #:key
+                            (vendor-dir "guix-vendor")
+                            #:allow-other-keys)
+  "Regenerate the Cargo.lock file with the current build inputs."
+  (when (file-exists? "Cargo.lock")
+    (begin
+      ;; Unfortunately we can't generate a Cargo.lock file until the checksums
+      ;; are generated, so we have an extra round of generate-all-checksums here.
+      (generate-all-checksums vendor-dir)
+      (delete-file "Cargo.lock")
+      (invoke "cargo" "generate-lockfile")))
+  #t)
+
+;; After the 'patch-generated-file-shebangs phase any vendored crates who have
+;; their shebangs patched will have a mismatch on their checksum.
+(define* (patch-cargo-checksums #:key
+                                (vendor-dir "guix-vendor")
+                                #:allow-other-keys)
+  "Patch the checksums of the vendored crates after patching their shebangs."
+  (generate-all-checksums vendor-dir)
+  #t)
+
 (define* (build #:key
                 skip-build?
                 (cargo-build-flags '("--release"))
@@ -162,7 +202,9 @@ directory = '" port)
     (replace 'configure configure)
     (replace 'build build)
     (replace 'check check)
-    (replace 'install install)))
+    (replace 'install install)
+    (add-after 'configure 'update-cargo-lock update-cargo-lock)
+    (add-after 'patch-generated-file-shebangs 'patch-cargo-checksums patch-cargo-checksums)))
 
 (define* (cargo-build #:key inputs (phases %standard-phases)
                       #:allow-other-keys #:rest args)
diff --git a/guix/build/go-build-system.scm b/guix/build/go-build-system.scm
index 858068ba98..3dac43c18a 100644
--- a/guix/build/go-build-system.scm
+++ b/guix/build/go-build-system.scm
@@ -135,6 +135,9 @@ of the package being built and its dependencies, and GOBIN, which determines
 where executables (\"commands\") are installed to.  This phase is sometimes used
 by packages that use (guix build-system gnu) but have a handful of Go
 dependencies, so it should be self-contained."
+  ;; The Go cache is required starting in Go 1.12.  We don't actually use it but
+  ;; we need it to be a writable directory.
+  (setenv "GOCACHE" "/tmp/go-cache")
   ;; Using the current working directory as GOPATH makes it easier for packagers
   ;; who need to manipulate the unpacked source code.
   (setenv "GOPATH" (getcwd))
diff --git a/guix/discovery.scm b/guix/discovery.scm
index 468b6c59de..7c5fed7f0e 100644
--- a/guix/discovery.scm
+++ b/guix/discovery.scm
@@ -51,13 +51,15 @@ DIRECTORY is not accessible."
       ((? symbol? type)
        type)))
 
+  (define (dot-prefixed? file)
+    (string-prefix? "." file))
+
   ;; Use 'scandir*' so we can avoid an extra 'lstat' for each entry, as
   ;; opposed to Guile's 'scandir' or 'file-system-fold'.
   (fold-right (lambda (entry result)
                 (match entry
-                  (("." . _)
-                   result)
-                  ((".." . _)
+                  (((? dot-prefixed?) . _)
+                   ;; Exclude ".", "..", and hidden files such as backups.
                    result)
                   ((name . properties)
                    (let ((absolute (string-append directory "/" name)))
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/gexp.scm b/guix/gexp.scm
index eef308b000..45cd5869f7 100644
--- a/guix/gexp.scm
+++ b/guix/gexp.scm
@@ -427,7 +427,9 @@ This is the declarative counterpart of 'gexp->script'."
     (($ <program-file> name gexp guile module-path)
      (gexp->script name gexp
                    #:module-path module-path
-                   #:guile (or guile (default-guile))))))
+                   #:guile (or guile (default-guile))
+                   #:system system
+                   #:target target))))
 
 (define-record-type <scheme-file>
   (%scheme-file name gexp splice?)
@@ -1345,6 +1347,7 @@ last one is created from the given <scheme-file> object."
 (define* (compiled-modules modules
                            #:key (name "module-import-compiled")
                            (system (%current-system))
+                           target
                            (guile (%guile-for-build))
                            (module-path %load-path)
                            (extensions '())
@@ -1355,7 +1358,8 @@ last one is created from the given <scheme-file> object."
                            (pre-load-modules? #t))
   "Return a derivation that builds a tree containing the `.go' files
 corresponding to MODULES.  All the MODULES are built in a context where
-they can refer to each other."
+they can refer to each other.  When TARGET is true, cross-compile MODULES for
+TARGET, a GNU triplet."
   (define total (length modules))
 
   (mlet %store-monad ((modules (imported-modules modules
@@ -1374,6 +1378,12 @@ they can refer to each other."
                       (srfi srfi-26)
                       (system base compile))
 
+         ;; TODO: Inline this on the next rebuild cycle.
+         (ungexp-splicing
+          (if target
+              (gexp ((use-modules (system base target))))
+              (gexp ())))
+
          (define (regular? file)
            (not (member file '("." ".."))))
 
@@ -1391,9 +1401,19 @@ they can refer to each other."
                                                    (gexp ()))))
                          (ungexp (* total (if pre-load-modules? 2 1)))
                          entry)
-                 (compile-file entry
-                               #:output-file output
-                               #:opts %auto-compilation-options)
+
+                 (ungexp-splicing
+                  (if target
+                      (gexp ((with-target (ungexp target)
+                               (lambda ()
+                                 (compile-file entry
+                                               #:output-file output
+                                               #:opts
+                                               %auto-compilation-options)))))
+                      (gexp ((compile-file entry
+                                           #:output-file output
+                                           #:opts %auto-compilation-options)))))
+
                  (+ 1 processed))))
 
          (define (process-directory directory output processed)
@@ -1494,7 +1514,7 @@ they can refer to each other."
               'guile-2.2))
 
 (define* (load-path-expression modules #:optional (path %load-path)
-                               #:key (extensions '()))
+                               #:key (extensions '()) system target)
   "Return as a monadic value a gexp that sets '%load-path' and
 '%load-compiled-path' to point to MODULES, a list of module names.  MODULES
 are searched for in PATH.  Return #f when MODULES and EXTENSIONS are empty."
@@ -1502,10 +1522,13 @@ are searched for in PATH.  Return #f when MODULES and EXTENSIONS are empty."
       (with-monad %store-monad
         (return #f))
       (mlet %store-monad ((modules  (imported-modules modules
-                                                      #:module-path path))
+                                                      #:module-path path
+                                                      #:system system))
                           (compiled (compiled-modules modules
                                                       #:extensions extensions
-                                                      #:module-path path)))
+                                                      #:module-path path
+                                                      #:system system
+                                                      #:target target)))
         (return (gexp (eval-when (expand load eval)
                         (set! %load-path
                           (cons (ungexp modules)
@@ -1527,14 +1550,18 @@ are searched for in PATH.  Return #f when MODULES and EXTENSIONS are empty."
 
 (define* (gexp->script name exp
                        #:key (guile (default-guile))
-                       (module-path %load-path))
+                       (module-path %load-path)
+                       (system (%current-system))
+                       target)
   "Return an executable script NAME that runs EXP using GUILE, with EXP's
 imported modules in its search path.  Look up EXP's modules in MODULE-PATH."
   (mlet %store-monad ((set-load-path
                        (load-path-expression (gexp-modules exp)
                                              module-path
                                              #:extensions
-                                             (gexp-extensions exp))))
+                                             (gexp-extensions exp)
+                                             #:system system
+                                             #:target target)))
     (gexp->derivation name
                       (gexp
                        (call-with-output-file (ungexp output)
@@ -1554,6 +1581,8 @@ imported modules in its search path.  Look up EXP's modules in MODULE-PATH."
 
                            (write '(ungexp exp) port)
                            (chmod port #o555))))
+                      #:system system
+                      #:target target
                       #:module-path module-path)))
 
 (define* (gexp->file name exp #:key
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/git.scm b/guix/git.scm
index 289537dedf..de98fed40c 100644
--- a/guix/git.scm
+++ b/guix/git.scm
@@ -139,29 +139,44 @@ of SHA1 string."
   "Switch to REPOSITORY's branch, commit or tag specified by REF.  Return the
 OID (roughly the commit hash) corresponding to REF."
   (define obj
-    (match ref
-      (('branch . branch)
-       (let ((oid (reference-target
-                   (branch-lookup repository branch BRANCH-REMOTE))))
-         (object-lookup repository oid)))
-      (('commit . commit)
-       (let ((len (string-length commit)))
-         ;; 'object-lookup-prefix' appeared in Guile-Git in Mar. 2018, so we
-         ;; can't be sure it's available.  Furthermore, 'string->oid' used to
-         ;; read out-of-bounds when passed a string shorter than 40 chars,
-         ;; which is why we delay calls to it below.
-         (if (< len 40)
-             (if (module-defined? (resolve-interface '(git object))
-                                  'object-lookup-prefix)
-                 (object-lookup-prefix repository (string->oid commit) len)
-                 (raise (condition
-                         (&message
-                          (message "long Git object ID is required")))))
-             (object-lookup repository (string->oid commit)))))
-      (('tag    . tag)
-       (let ((oid (reference-name->oid repository
-                                       (string-append "refs/tags/" tag))))
-         (object-lookup repository oid)))))
+    (let resolve ((ref ref))
+      (match ref
+        (('branch . branch)
+         (let ((oid (reference-target
+                     (branch-lookup repository branch BRANCH-REMOTE))))
+           (object-lookup repository oid)))
+        (('commit . commit)
+         (let ((len (string-length commit)))
+           ;; 'object-lookup-prefix' appeared in Guile-Git in Mar. 2018, so we
+           ;; can't be sure it's available.  Furthermore, 'string->oid' used to
+           ;; read out-of-bounds when passed a string shorter than 40 chars,
+           ;; which is why we delay calls to it below.
+           (if (< len 40)
+               (if (module-defined? (resolve-interface '(git object))
+                                    'object-lookup-prefix)
+                   (object-lookup-prefix repository (string->oid commit) len)
+                   (raise (condition
+                           (&message
+                            (message "long Git object ID is required")))))
+               (object-lookup repository (string->oid commit)))))
+        (('tag-or-commit . str)
+         (if (or (> (string-length str) 40)
+                 (not (string-every char-set:hex-digit str)))
+             (resolve `(tag . ,str))              ;definitely a tag
+             (catch 'git-error
+               (lambda ()
+                 (resolve `(tag . ,str)))
+               (lambda _
+                 ;; There's no such tag, so it must be a commit ID.
+                 (resolve `(commit . ,str))))))
+        (('tag    . tag)
+         (let ((oid (reference-name->oid repository
+                                         (string-append "refs/tags/" tag))))
+           ;; Get the commit that the tag at OID refers to.  This is not
+           ;; strictly needed, but it's more consistent to always return the
+           ;; OID of a commit.
+           (object-lookup repository
+                          (tag-target-id (tag-lookup repository oid))))))))
 
   (reset repository obj RESET_HARD)
   (object-id obj))
@@ -218,8 +233,8 @@ please upgrade Guile-Git.~%"))))
 values: the cache directory name, and the SHA1 commit (a string) corresponding
 to REF.
 
-REF is pair whose key is [branch | commit | tag] and value the associated
-data, respectively [<branch name> | <sha1> | <tag name>].
+REF is pair whose key is [branch | commit | tag | tag-or-commit ] and value
+the associated data: [<branch name> | <sha1> | <tag name> | <string>].
 
 When RECURSIVE? is true, check out submodules as well, if any."
   (define canonical-ref
@@ -319,7 +334,7 @@ Log progress and checkout info to LOG-PORT."
   git-checkout?
   (url     git-checkout-url)
   (branch  git-checkout-branch (default "master"))
-  (commit  git-checkout-commit (default #f))
+  (commit  git-checkout-commit (default #f))      ;#f | tag | commit
   (recursive? git-checkout-recursive? (default #f)))
 
 (define* (latest-repository-commit* url #:key ref recursive? log-port)
@@ -358,7 +373,7 @@ Log progress and checkout info to LOG-PORT."
     (($ <git-checkout> url branch commit recursive?)
      (latest-repository-commit* url
                                 #:ref (if commit
-                                          `(commit . ,commit)
+                                          `(tag-or-commit . ,commit)
                                           `(branch . ,branch))
                                 #:recursive? recursive?
                                 #:log-port (current-error-port)))))
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/build.scm b/guix/scripts/build.scm
index ec58ba871b..3ee0b737fe 100644
--- a/guix/scripts/build.scm
+++ b/guix/scripts/build.scm
@@ -341,10 +341,15 @@ strings like \"guile-next=cabba9e\" meaning that packages are built using
   (define (replace old url commit)
     (package
       (inherit old)
-      (version (string-append "git."
-                              (if (< (string-length commit) 7)
-                                  commit
-                                  (string-take commit 7))))
+      (version (if (and (> (string-length commit) 1)
+                        (string-prefix? "v" commit)
+                        (char-set-contains? char-set:digit
+                                            (string-ref commit 1)))
+                   (string-drop commit 1)        ;looks like a tag like "v1.0"
+                   (string-append "git."
+                                  (if (< (string-length commit) 7)
+                                      commit
+                                      (string-take commit 7)))))
       (source (git-checkout (url url) (commit commit)
                             (recursive? #t)))))
 
diff --git a/guix/scripts/deploy.scm b/guix/scripts/deploy.scm
index 978cfb2a81..52bba3f3bf 100644
--- a/guix/scripts/deploy.scm
+++ b/guix/scripts/deploy.scm
@@ -23,6 +23,8 @@
   #:use-module (guix scripts build)
   #:use-module (guix store)
   #:use-module (guix ui)
+  #:use-module (guix utils)
+  #:use-module (guix grafts)
   #:use-module (ice-9 format)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-37)
@@ -40,6 +42,8 @@
 (define (show-help)
   (display (G_ "Usage: guix deploy [OPTION] FILE...
 Perform the deployment specified by FILE.\n"))
+  (display (G_ "
+  -s, --system=SYSTEM    attempt to build for SYSTEM--e.g., \"i686-linux\""))
   (show-build-options-help)
   (newline)
   (display (G_ "
@@ -54,10 +58,14 @@ Perform the deployment specified by FILE.\n"))
                  (lambda args
                    (show-help)
                    (exit 0)))
+         (option '(#\s "system") #t #f
+                 (lambda (opt name arg result)
+                   (alist-cons 'system arg
+                               (alist-delete 'system result eq?))))
          %standard-build-options))
 
 (define %default-options
-  '((system . ,(%current-system))
+  `((system . ,(%current-system))
     (substitutes? . #t)
     (build-hook? . #t)
     (graft? . #t)
@@ -80,5 +88,7 @@ Perform the deployment specified by FILE.\n"))
       (set-build-options-from-command-line store opts)
       (for-each (lambda (machine)
                   (info (G_ "deploying to ~a...") (machine-display-name machine))
-                  (run-with-store store (deploy-machine machine)))
+                  (parameterize ((%current-system (assq-ref opts 'system))
+                                 (%graft? (assq-ref opts 'graft?)))
+                    (run-with-store store (deploy-machine machine))))
                 machines))))
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/scripts/system.scm b/guix/scripts/system.scm
index 67a4071684..9fc3a10e98 100644
--- a/guix/scripts/system.scm
+++ b/guix/scripts/system.scm
@@ -41,6 +41,7 @@
                                        delete-matching-generations)
   #:use-module (guix graph)
   #:use-module (guix scripts graph)
+  #:use-module (guix scripts system reconfigure)
   #:use-module (guix build utils)
   #:use-module (guix progress)
   #:use-module ((guix build syscalls) #:select (terminal-columns))
@@ -178,43 +179,9 @@ TARGET, and register them."
 
     (return *unspecified*)))
 
-(define* (install-bootloader installer
-                             #:key
-                             bootcfg bootcfg-file
-                             target)
-  "Run INSTALLER, a bootloader installation script, with error handling, in
-%STORE-MONAD."
-  (mlet %store-monad ((installer-drv (if installer
-                                         (lower-object installer)
-                                         (return #f)))
-                      (bootcfg       (lower-object bootcfg)))
-    (let* ((gc-root      (string-append target %gc-roots-directory
-                                        "/bootcfg"))
-           (temp-gc-root (string-append gc-root ".new"))
-           (install (and installer-drv
-                         (derivation->output-path installer-drv)))
-           (bootcfg (derivation->output-path bootcfg)))
-      ;; Prepare the symlink to bootloader config file to make sure that it's
-      ;; a GC root when 'installer-drv' completes (being a bit paranoid.)
-      (switch-symlinks temp-gc-root bootcfg)
-
-      (unless (false-if-exception
-               (begin
-                 (install-boot-config bootcfg bootcfg-file target)
-                 (when install
-                   (save-load-path-excursion (primitive-load install)))))
-        (delete-file temp-gc-root)
-        (leave (G_ "failed to install bootloader ~a~%") install))
-
-      ;; Register bootloader config file as a GC root so that its dependencies
-      ;; (background image, font, etc.) are not reclaimed.
-      (rename-file temp-gc-root gc-root)
-      (return #t))))
-
 (define* (install os-drv target
                   #:key (log-port (current-output-port))
-                  bootloader-installer install-bootloader?
-                  bootcfg bootcfg-file)
+                  install-bootloader? bootloader bootcfg)
   "Copy the closure of BOOTCFG, which includes the output of OS-DRV, to
 directory TARGET.  TARGET must be an absolute directory name since that's what
 'register-path' expects.
@@ -265,10 +232,11 @@ the ownership of '~a' may be incorrect!~%")
         (populate os-dir target)
 
         (mwhen install-bootloader?
-          (install-bootloader bootloader-installer
-                              #:bootcfg bootcfg
-                              #:bootcfg-file bootcfg-file
-                              #:target target))))))
+          (install-bootloader local-eval bootloader bootcfg
+                              #:target target)
+          (return
+           (info (G_ "bootloader successfully installed on '~a'~%")
+                 (bootloader-configuration-target bootloader))))))))
 
 
 ;;;
@@ -335,82 +303,6 @@ unload."
        (warning (G_ "failed to obtain list of shepherd services~%"))
        (return #f)))))
 
-(define (upgrade-shepherd-services os)
-  "Upgrade the Shepherd (PID 1) by unloading obsolete services and loading new
-services specified in OS and not currently running.
-
-This is currently very conservative in that it does not stop or unload any
-running service.  Unloading or stopping the wrong service ('udev', say) could
-bring the system down."
-  (define new-services
-    (service-value
-     (fold-services (operating-system-services os)
-                    #:target-type shepherd-root-service-type)))
-
-  ;; Arrange to simply emit a warning if the service upgrade fails.
-  (with-shepherd-error-handling
-   (call-with-service-upgrade-info new-services
-     (lambda (to-restart to-unload)
-        (for-each (lambda (unload)
-                    (info (G_ "unloading service '~a'...~%") unload)
-                    (unload-service unload))
-                  to-unload)
-
-        (with-monad %store-monad
-          (munless (null? new-services)
-            (let ((new-service-names  (map shepherd-service-canonical-name new-services))
-                  (to-restart-names   (map shepherd-service-canonical-name to-restart))
-                  (to-start           (filter shepherd-service-auto-start? new-services)))
-              (info (G_ "loading new services:~{ ~a~}...~%") new-service-names)
-              (unless (null? to-restart-names)
-                ;; Listing TO-RESTART-NAMES in the message below wouldn't help
-                ;; because many essential services cannot be meaningfully
-                ;; restarted.  See <https://debbugs.gnu.org/cgi/bugreport.cgi?bug=22039#30>.
-                (format #t (G_ "To complete the upgrade, run 'herd restart SERVICE' to stop,
-upgrade, and restart each service that was not automatically restarted.\n")))
-              (mlet %store-monad ((files (mapm %store-monad
-                                               (compose lower-object
-                                                        shepherd-service-file)
-                                               new-services)))
-                ;; Here we assume that FILES are exactly those that were computed
-                ;; as part of the derivation that built OS, which is normally the
-                ;; case.
-                (load-services/safe (map derivation->output-path files))
-
-                (for-each start-service
-                          (map shepherd-service-canonical-name to-start))
-                (return #t)))))))))
-
-(define* (switch-to-system os
-                           #:optional (profile %system-profile))
-  "Make a new generation of PROFILE pointing to the directory of OS, switch to
-it atomically, and then run OS's activation script."
-  (mlet* %store-monad ((drv (operating-system-derivation os))
-                       (script (lower-object (operating-system-activation-script os))))
-    (let* ((system     (derivation->output-path drv))
-           (number     (+ 1 (generation-number profile)))
-           (generation (generation-file-name profile number)))
-      (switch-symlinks generation system)
-      (switch-symlinks profile generation)
-
-      (format #t (G_ "activating system...~%"))
-
-      ;; The activation script may change $PATH, among others, so protect
-      ;; against that.
-      (save-environment-excursion
-       ;; Tell 'activate-current-system' what the new system is.
-       (setenv "GUIX_NEW_SYSTEM" system)
-
-       ;; The activation script may modify '%load-path' & co., so protect
-       ;; against that.  This is necessary to ensure that
-       ;; 'upgrade-shepherd-services' gets to see the right modules when it
-       ;; computes derivations with 'gexp->derivation'.
-       (save-load-path-excursion
-        (primitive-load (derivation->output-path script))))
-
-      ;; Finally, try to update system services.
-      (upgrade-shepherd-services os))))
-
 (define-syntax-rule (unless-file-not-found exp)
   (catch 'system-error
     (lambda ()
@@ -505,18 +397,13 @@ STORE is an open connection to the store."
                      ((bootloader-configuration-file-generator bootloader)
                       bootloader-config entries
                       #:old-entries old-entries)))
-           (bootcfg-file -> (bootloader-configuration-file bootloader))
-           (target -> "/")
            (drvs -> (list bootcfg)))
         (mbegin %store-monad
           (show-what-to-build* drvs)
           (built-derivations drvs)
-          ;; Only install bootloader configuration file. Thus, no installer is
-          ;; provided here.
-          (install-bootloader #f
-                              #:bootcfg bootcfg
-                              #:bootcfg-file bootcfg-file
-                              #:target target))))))
+          ;; Only install bootloader configuration file.
+          (install-bootloader local-eval bootloader-config bootcfg
+                              #:run-installer? #f))))))
 
 
 ;;;
@@ -820,8 +707,17 @@ and TARGET arguments."
                                         (condition-message c))
                                 (exit 1)))
                        (#$installer #$bootloader #$device #$target)
-                       (format #t "bootloader successfully installed on '~a'~%"
-                               #$device))))))
+                       (info (G_ "bootloader successfully installed on '~a'~%")
+                             #$device))))))
+
+(define (local-eval exp)
+  "Evaluate EXP, a G-Expression, in-place."
+  (mlet* %store-monad ((lowered (lower-gexp exp))
+                       (_ (built-derivations (lowered-gexp-inputs lowered))))
+    (save-load-path-excursion
+     (set! %load-path (lowered-gexp-load-path lowered))
+     (set! %load-compiled-path (lowered-gexp-load-compiled-path lowered))
+     (return (primitive-eval (lowered-gexp-sexp lowered))))))
 
 (define* (perform-action action os
                          #:key skip-safety-checks?
@@ -858,19 +754,12 @@ static checks."
         (map boot-parameters->menu-entry (profile-boot-parameters))))
 
   (define bootloader
-    (bootloader-configuration-bootloader (operating-system-bootloader os)))
+    (operating-system-bootloader os))
 
   (define bootcfg
     (and (memq action '(init reconfigure))
          (operating-system-bootcfg os menu-entries)))
 
-  (define bootloader-script
-    (let ((installer (bootloader-installer bootloader))
-          (target    (or target "/")))
-      (bootloader-installer-script installer
-                                   (bootloader-package bootloader)
-                                   bootloader-target target)))
-
   (when (eq? action 'reconfigure)
     (maybe-suggest-running-guix-pull))
 
@@ -897,9 +786,7 @@ static checks."
        ;; See <http://bugs.gnu.org/21068>.
        (drvs      (mapm %store-monad lower-object
                         (if (memq action '(init reconfigure))
-                            (if install-bootloader?
-                                (list sys bootcfg bootloader-script)
-                                (list sys bootcfg))
+                            (list sys bootcfg)
                             (list sys))))
        (%         (if derivations-only?
                       (return (for-each (compose println derivation-file-name)
@@ -909,28 +796,32 @@ static checks."
 
     (if (or dry-run? derivations-only?)
         (return #f)
-        (let ((bootcfg-file (bootloader-configuration-file bootloader)))
+        (begin
           (for-each (compose println derivation->output-path)
                     drvs)
 
           (case action
             ((reconfigure)
+             (newline)
+             (format #t (G_ "activating system...~%"))
              (mbegin %store-monad
-               (switch-to-system os)
+               (switch-to-system local-eval os)
                (mwhen install-bootloader?
-                 (install-bootloader bootloader-script
-                                     #:bootcfg bootcfg
-                                     #:bootcfg-file bootcfg-file
-                                     #:target "/"))))
+                 (install-bootloader local-eval bootloader bootcfg
+                                     #:target (or target "/"))
+                 (return
+                  (info (G_ "bootloader successfully installed on '~a'~%")
+                        (bootloader-configuration-target bootloader))))
+               (with-shepherd-error-handling
+                  (upgrade-shepherd-services local-eval os))))
             ((init)
              (newline)
              (format #t (G_ "initializing operating system under '~a'...~%")
                      target)
              (install sys (canonicalize-path target)
                       #:install-bootloader? install-bootloader?
-                      #:bootcfg bootcfg
-                      #:bootcfg-file bootcfg-file
-                      #:bootloader-installer bootloader-script))
+                      #:bootloader bootloader
+                      #:bootcfg bootcfg))
             (else
              ;; All we had to do was to build SYS and maybe register an
              ;; indirect GC root.
diff --git a/guix/scripts/system/reconfigure.scm b/guix/scripts/system/reconfigure.scm
new file mode 100644
index 0000000000..dee0c24bd2
--- /dev/null
+++ b/guix/scripts/system/reconfigure.scm
@@ -0,0 +1,232 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2014, 2015, 2016, 2017, 2018, 2019 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2016 Alex Kost <alezost@gmail.com>
+;;; Copyright © 2016, 2017, 2018 Chris Marusich <cmmarusich@gmail.com>
+;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
+;;; Copyright © 2018 Ricardo Wurmus <rekado@elephly.net>
+;;; Copyright © 2019 Christopher Baines <mail@cbaines.net>
+;;; Copyright © 2019 Jakob L. Kreuze <zerodaysfordays@sdf.lonestar.org>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (guix scripts system reconfigure)
+  #:autoload   (gnu packages gnupg) (guile-gcrypt)
+  #:use-module (gnu bootloader)
+  #:use-module (gnu services)
+  #:use-module (gnu services herd)
+  #:use-module (gnu services shepherd)
+  #:use-module (gnu system)
+  #:use-module (guix gexp)
+  #:use-module (guix modules)
+  #:use-module (guix monads)
+  #:use-module (guix store)
+  #:use-module (ice-9 match)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-11)
+  #:export (switch-system-program
+            switch-to-system
+
+            upgrade-services-program
+            upgrade-shepherd-services
+
+            install-bootloader-program
+            install-bootloader))
+
+;;; Commentary:
+;;;
+;;; This module implements the "effectful" parts of system
+;;; reconfiguration. Although building a system derivation is a pure
+;;; operation, a number of impure operations must be carried out for the
+;;; system configuration to be realized -- chiefly, creation of generation
+;;; symlinks and invocation of activation scripts.
+;;;
+;;; Code:
+
+
+;;;
+;;; Profile creation.
+;;;
+
+(define* (switch-system-program os #:optional profile)
+  "Return an executable store item that, upon being evaluated, will create a
+new generation of PROFILE pointing to the directory of OS, switch to it
+atomically, and run OS's activation script."
+  (program-file
+   "switch-to-system.scm"
+   (with-extensions (list guile-gcrypt)
+     (with-imported-modules (source-module-closure '((guix config)
+                                                     (guix profiles)
+                                                     (guix utils)))
+       #~(begin
+           (use-modules (guix config)
+                        (guix profiles)
+                        (guix utils))
+
+           (define profile
+             (or #$profile (string-append %state-directory "/profiles/system")))
+
+           (let* ((number (1+ (generation-number profile)))
+                  (generation (generation-file-name profile number)))
+             (switch-symlinks generation #$os)
+             (switch-symlinks profile generation)
+             (setenv "GUIX_NEW_SYSTEM" #$os)
+             (primitive-load #$(operating-system-activation-script os))))))))
+
+(define* (switch-to-system eval os #:optional profile)
+  "Using EVAL, a monadic procedure taking a single G-Expression as an argument,
+create a new generation of PROFILE pointing to the directory of OS, switch to
+it atomically, and run OS's activation script."
+  (eval #~(primitive-load #$(switch-system-program os profile))))
+
+
+;;;
+;;; Services.
+;;;
+
+(define (running-services eval)
+  "Using EVAL, a monadic procedure taking a single G-Expression as an argument,
+return the <live-service> objects that are currently running on MACHINE."
+  (define exp
+    (with-imported-modules '((gnu services herd))
+      #~(begin
+          (use-modules (gnu services herd))
+          (let ((services (current-services)))
+            (and services
+                 ;; 'live-service-running' is ignored, as we can't necessarily
+                 ;; serialize arbitrary objects. This should be fine for now,
+                 ;; since 'machine-current-services' is not exposed publicly,
+                 ;; and the resultant <live-service> objects are only used for
+                 ;; resolving service dependencies.
+                 (map (lambda (service)
+                        (list (live-service-provision service)
+                              (live-service-requirement service)))
+                      services))))))
+  (mlet %store-monad ((services (eval exp)))
+    (return (map (match-lambda
+                   ((provision requirement)
+                    (live-service provision requirement #f)))
+                 services))))
+
+;; XXX: Currently, this does NOT attempt to restart running services. See
+;; <https://issues.guix.info/issue/33508> for details.
+(define (upgrade-services-program service-files to-start to-unload to-restart)
+  "Return an executable store item that, upon being evaluated, will upgrade
+the Shepherd (PID 1) by unloading obsolete services and loading new
+services. SERVICE-FILES is a list of Shepherd service files to load, and
+TO-START, TO-UNLOAD, and TO-RESTART are lists of the Shepherd services'
+canonical names (symbols)."
+  (program-file
+   "upgrade-shepherd-services.scm"
+   (with-imported-modules '((gnu services herd))
+    #~(begin
+        (use-modules (gnu services herd)
+                     (srfi srfi-1))
+
+        ;; Load the service files for any new services.
+        (load-services/safe '#$service-files)
+
+        ;; Unload obsolete services and start new services.
+        (for-each unload-service '#$to-unload)
+        (for-each start-service '#$to-start)))))
+
+(define* (upgrade-shepherd-services eval os)
+  "Using EVAL, a monadic procedure taking a single G-Expression as an argument,
+upgrade the Shepherd (PID 1) by unloading obsolete services and loading new
+services as defined by OS."
+  (define target-services
+    (service-value
+     (fold-services (operating-system-services os)
+                    #:target-type shepherd-root-service-type)))
+
+  (mlet* %store-monad ((live-services (running-services eval)))
+    (let*-values (((to-unload to-restart)
+                   (shepherd-service-upgrade live-services target-services)))
+      (let* ((to-unload (map live-service-canonical-name to-unload))
+             (to-restart (map shepherd-service-canonical-name to-restart))
+             (to-start (lset-difference eqv?
+                                        (map shepherd-service-canonical-name
+                                             target-services)
+                                        (map live-service-canonical-name
+                                             live-services)))
+             (service-files (map shepherd-service-file target-services)))
+        (eval #~(primitive-load #$(upgrade-services-program service-files
+                                                            to-start
+                                                            to-unload
+                                                            to-restart)))))))
+
+
+;;;
+;;; Bootloader configuration.
+;;;
+
+(define (install-bootloader-program installer bootloader-package bootcfg
+                                    bootcfg-file device target)
+  "Return an executable store item that, upon being evaluated, will install
+BOOTCFG to BOOTCFG-FILE, a target file name, on DEVICE, a file system device,
+at TARGET, a mount point, and subsequently run INSTALLER from
+BOOTLOADER-PACKAGE."
+  (program-file
+   "install-bootloader.scm"
+   (with-extensions (list guile-gcrypt)
+     (with-imported-modules (source-module-closure '((gnu build bootloader)
+                                                     (gnu build install)
+                                                     (guix store)
+                                                     (guix utils)))
+       #~(begin
+           (use-modules (gnu build bootloader)
+                        (gnu build install)
+                        (guix build utils)
+                        (guix store)
+                        (guix utils)
+                        (ice-9 binary-ports)
+                        (srfi srfi-34)
+                        (srfi srfi-35))
+           (let* ((gc-root (string-append #$target %gc-roots-directory "/bootcfg"))
+                  (temp-gc-root (string-append gc-root ".new")))
+             (switch-symlinks temp-gc-root gc-root)
+             (install-boot-config #$bootcfg #$bootcfg-file #$target)
+             ;; Preserve the previous activation's garbage collector root
+             ;; until the bootloader installer has run, so that a failure in
+             ;; the bootloader's installer script doesn't leave the user with
+             ;; a broken installation.
+             (when #$installer
+               (catch #t
+                 (lambda ()
+                   (#$installer #$bootloader-package #$device #$target))
+                 (lambda args
+                   (delete-file temp-gc-root)
+                   (apply throw args))))
+             (rename-file temp-gc-root gc-root)))))))
+
+(define* (install-bootloader eval configuration bootcfg
+                             #:key
+                             (run-installer? #t)
+                             (target "/"))
+  "Using EVAL, a monadic procedure taking a single G-Expression as an argument,
+configure the bootloader on TARGET such that OS will be booted by default and
+additional configurations specified by MENU-ENTRIES can be selected."
+  (let* ((bootloader (bootloader-configuration-bootloader configuration))
+         (installer (and run-installer?
+                         (bootloader-installer bootloader)))
+         (package (bootloader-package bootloader))
+         (device (bootloader-configuration-target configuration))
+         (bootcfg-file (bootloader-configuration-file bootloader)))
+    (eval #~(primitive-load #$(install-bootloader-program installer
+                                                          package
+                                                          bootcfg
+                                                          bootcfg-file
+                                                          device
+                                                          target)))))
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."