Merge branch 'master' into core-updates

10 files changed, 634 insertions, 36 deletions

diff --git a/build-aux/build-self.scm b/build-aux/build-self.scm
index cc702490df..a1335fea1d 100644
--- a/build-aux/build-self.scm
+++ b/build-aux/build-self.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2014, 2016 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2014, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -22,6 +22,7 @@
   #:use-module (guix config)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-19)
+  #:use-module (ice-9 match)
   #:export (build))
 
 ;;; Commentary:
@@ -58,11 +59,43 @@
 (define xz
   (first (find-best-packages-by-name "xz" #f)))
 
+(define (false-if-wrong-guile package)
+  "Return #f if PACKAGE depends on the \"wrong\" major version of Guile (e.g.,
+2.0 instead of 2.2), otherwise return PACKAGE."
+  (let ((guile (any (match-lambda
+                      ((label (? package? dep) _ ...)
+                       (and (string=? (package-name dep) "guile")
+                            dep)))
+                    (package-direct-inputs package))))
+    (and (or (not guile)
+             (string-prefix? (effective-version)
+                             (package-version guile)))
+         package)))
+
+(define (package-for-current-guile . names)
+  "Return the package with one of the given NAMES that depends on the current
+Guile major version (2.0 or 2.2), or #f if none of the packages matches."
+  (let loop ((names names))
+    (match names
+      (()
+       #f)
+      ((name rest ...)
+       (match (find-best-packages-by-name name #f)
+         (()
+          (loop rest))
+         ((first _ ...)
+          (or (false-if-wrong-guile first)
+              (loop rest))))))))
+
 (define guile-json
-  (first (find-best-packages-by-name "guile-json" #f)))
+  (package-for-current-guile "guile-json"
+                             "guile2.2-json"
+                             "guile2.0-json"))
 
 (define guile-ssh
-  (first (find-best-packages-by-name "guile-ssh" #f)))
+  (package-for-current-guile "guile-ssh"
+                             "guile2.2-ssh"
+                             "guile2.0-ssh"))
 
 
 ;; The actual build procedure.
@@ -80,6 +113,17 @@ person's version identifier."
   ;; XXX: Replace with a Git commit id.
   (date->string (current-date 0) "~Y~m~d.~H"))
 
+(define (guile-for-build)
+  "Return a derivation for Guile 2.0 or 2.2, whichever matches the currently
+running Guile."
+  (package->derivation (cond-expand
+                         (guile-2.2
+                          (canonical-package
+                           (specification->package "guile@2.2")))
+                         (else
+                          (canonical-package
+                           (specification->package "guile@2.0"))))))
+
 ;; The procedure below is our return value.
 (define* (build source
                 #:key verbose? (version (date-version-string))
@@ -104,15 +148,19 @@ files."
     #~(begin
         (use-modules (guix build pull))
 
-        (let ((json (string-append #$guile-json "/share/guile/site/2.0")))
+        (let ((json (string-append #$guile-json "/share/guile/site/"
+                                   #$(effective-version))))
           (set! %load-path
-                (cons* json
-                       (string-append #$guile-ssh "/share/guile/site/2.0")
-                       %load-path))
+            (cons* json
+                   (string-append #$guile-ssh "/share/guile/site/"
+                                  #$(effective-version))
+                   %load-path))
           (set! %load-compiled-path
-                (cons* json
-                       (string-append #$guile-ssh "/lib/guile/2.0/site-ccache")
-                       %load-compiled-path)))
+            (cons* json
+                   (string-append #$guile-ssh "/lib/guile/"
+                                  #$(effective-version)
+                                  "/site-ccache")
+                   %load-compiled-path)))
 
         ;; XXX: The 'guile-ssh' package prior to Guix commit 92b7258 was
         ;; broken: libguile-ssh could not be found.  Work around that.
@@ -146,13 +194,21 @@ files."
                                      (current-error-port)
                                      (%make-void-port "w")))))
 
-  (gexp->derivation "guix-latest" builder
-                    #:modules '((guix build pull)
-                                (guix build utils))
+  (mlet %store-monad ((guile (guile-for-build)))
+    (gexp->derivation "guix-latest" builder
+                      #:modules '((guix build pull)
+                                  (guix build utils)
+
+                                  ;; Closure of (guix modules).
+                                  (guix modules)
+                                  (guix memoization)
+                                  (guix sets))
+
+                      ;; Arrange so that our own (guix build …) modules are
+                      ;; used.
+                      #:module-path (list (top-source-directory))
 
-                    ;; Arrange so that our own (guix build …) modules are
-                    ;; used.
-                    #:module-path (list (top-source-directory))))
+                      #:guile-for-build guile)))
 
 ;; This file is loaded by 'guix pull'; return it the build procedure.
 build
diff --git a/build-aux/check-available-binaries.scm b/build-aux/check-available-binaries.scm
index 0060a8669e..b832d99935 100644
--- a/build-aux/check-available-binaries.scm
+++ b/build-aux/check-available-binaries.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2013, 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2013, 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -38,10 +38,13 @@
                                %hydra-supported-systems))
            (cross  (map (cut package-cross-derivation store
                              %bootstrap-tarballs <>)
-                        '("mips64el-linux-gnuabi64")))
+                        '("mips64el-linux-gnu"
+                          "arm-linux-gnueabihf")))
            (total  (append native cross)))
 
-      (set-build-options store #:use-substitutes? #t)
+      (set-build-options store
+                         #:use-substitutes? #t
+                         #:substitute-urls %default-substitute-urls)
       (let* ((total     (map derivation->output-path total))
              (available (substitutable-paths store total))
              (missing   (lset-difference string=? total available)))
diff --git a/build-aux/check-final-inputs-self-contained.scm b/build-aux/check-final-inputs-self-contained.scm
index dc44c4b636..dfb6a72f24 100644
--- a/build-aux/check-final-inputs-self-contained.scm
+++ b/build-aux/check-final-inputs-self-contained.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -57,7 +57,7 @@
 if it does."
   (let ((references (substitutable-references substitute)))
     (when (any (cut string-contains <> "boot") references)
-      (leave (_ "'~a' refers to bootstrap inputs: ~s~%")
+      (leave (G_ "'~a' refers to bootstrap inputs: ~s~%")
              (substitutable-path substitute) references))))
 
 (define (test-final-inputs store system)
@@ -71,7 +71,7 @@ refer to the bootstrap tools."
                                 (string=? (substitutable-path substitute)
                                           dir))
                               available)
-                  (leave (_ "~a (system: ~a) has no substitute~%")
+                  (leave (G_ "~a (system: ~a) has no substitute~%")
                          dir system)))
               inputs)
 
diff --git a/build-aux/compile-all.scm b/build-aux/compile-all.scm
index d077d75229..147bb80196 100644
--- a/build-aux/compile-all.scm
+++ b/build-aux/compile-all.scm
@@ -24,7 +24,10 @@
              (guix build utils))
 
 (define warnings
-  '(unsupported-warning format unbound-variable arity-mismatch))
+  ;; FIXME: 'format' is missing because it reports "non-literal format
+  ;; strings" due to the fact that we use 'G_' instead of '_'.  We'll need
+  ;; help from Guile to solve this.
+  '(unsupported-warning unbound-variable arity-mismatch))
 
 (define host (getenv "host"))
 
diff --git a/build-aux/download.scm b/build-aux/download.scm
index 0e98bef55b..8dfa914603 100644
--- a/build-aux/download.scm
+++ b/build-aux/download.scm
@@ -42,17 +42,15 @@
   (match (string-tokenize file (char-set-complement (char-set #\/)))
     ((_ ... system basename)
      (string->uri
-       (match system
-        ("aarch64-linux"
-         (string-append "http://flashner.co.il/guix/bootstrap/aarch64-linux"
-                        "/20170217/" basename))
-        (_ (string-append %url-base "/" system
-                          (match system
-                                 ("armhf-linux"
-                                  "/20150101/")
-                                 (_
-                                  "/20131110/"))
-                          basename)))))))
+      (string-append %url-base "/" system
+                     (match system
+                       ("aarch64-linux"
+                        "/20170217/")
+                       ("armhf-linux"
+                        "/20150101/")
+                       (_
+                        "/20131110/"))
+                     basename)))))
 
 (match (command-line)
   ((_ file expected-hash)
diff --git a/build-aux/git-version-gen b/build-aux/git-version-gen
new file mode 100755
index 0000000000..079849d5e5
--- /dev/null
+++ b/build-aux/git-version-gen
@@ -0,0 +1,226 @@
+#!/bin/sh
+# Print a version string.
+scriptversion=2017-01-09.19; # UTC
+
+# Copyright (C) 2007-2017 Free Software Foundation, Inc.
+#
+# This program 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.
+#
+# This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# This script is derived from GIT-VERSION-GEN from GIT: http://git.or.cz/.
+# It may be run two ways:
+# - from a git repository in which the "git describe" command below
+#   produces useful output (thus requiring at least one signed tag)
+# - from a non-git-repo directory containing a .tarball-version file, which
+#   presumes this script is invoked like "./git-version-gen .tarball-version".
+
+# In order to use intra-version strings in your project, you will need two
+# separate generated version string files:
+#
+# .tarball-version - present only in a distribution tarball, and not in
+#   a checked-out repository.  Created with contents that were learned at
+#   the last time autoconf was run, and used by git-version-gen.  Must not
+#   be present in either $(srcdir) or $(builddir) for git-version-gen to
+#   give accurate answers during normal development with a checked out tree,
+#   but must be present in a tarball when there is no version control system.
+#   Therefore, it cannot be used in any dependencies.  GNUmakefile has
+#   hooks to force a reconfigure at distribution time to get the value
+#   correct, without penalizing normal development with extra reconfigures.
+#
+# .version - present in a checked-out repository and in a distribution
+#   tarball.  Usable in dependencies, particularly for files that don't
+#   want to depend on config.h but do want to track version changes.
+#   Delete this file prior to any autoconf run where you want to rebuild
+#   files to pick up a version string change; and leave it stale to
+#   minimize rebuild time after unrelated changes to configure sources.
+#
+# As with any generated file in a VC'd directory, you should add
+# /.version to .gitignore, so that you don't accidentally commit it.
+# .tarball-version is never generated in a VC'd directory, so needn't
+# be listed there.
+#
+# Use the following line in your configure.ac, so that $(VERSION) will
+# automatically be up-to-date each time configure is run (and note that
+# since configure.ac no longer includes a version string, Makefile rules
+# should not depend on configure.ac for version updates).
+#
+# AC_INIT([GNU project],
+#         m4_esyscmd([build-aux/git-version-gen .tarball-version]),
+#         [bug-project@example])
+#
+# Then use the following lines in your Makefile.am, so that .version
+# will be present for dependencies, and so that .version and
+# .tarball-version will exist in distribution tarballs.
+#
+# EXTRA_DIST = $(top_srcdir)/.version
+# BUILT_SOURCES = $(top_srcdir)/.version
+# $(top_srcdir)/.version:
+#	echo $(VERSION) > $@-t && mv $@-t $@
+# dist-hook:
+#	echo $(VERSION) > $(distdir)/.tarball-version
+
+
+me=$0
+
+version="git-version-gen $scriptversion
+
+Copyright 2011 Free Software Foundation, Inc.
+There is NO warranty.  You may redistribute this software
+under the terms of the GNU General Public License.
+For more information about these matters, see the files named COPYING."
+
+usage="\
+Usage: $me [OPTION]... \$srcdir/.tarball-version [TAG-NORMALIZATION-SED-SCRIPT]
+Print a version string.
+
+Options:
+
+   --prefix PREFIX    prefix of git tags (default 'v')
+   --fallback VERSION
+                      fallback version to use if \"git --version\" fails
+
+   --help             display this help and exit
+   --version          output version information and exit
+
+Running without arguments will suffice in most cases."
+
+prefix=v
+fallback=
+
+while test $# -gt 0; do
+  case $1 in
+    --help) echo "$usage"; exit 0;;
+    --version) echo "$version"; exit 0;;
+    --prefix) shift; prefix=${1?};;
+    --fallback) shift; fallback=${1?};;
+    -*)
+      echo "$0: Unknown option '$1'." >&2
+      echo "$0: Try '--help' for more information." >&2
+      exit 1;;
+    *)
+      if test "x$tarball_version_file" = x; then
+        tarball_version_file="$1"
+      elif test "x$tag_sed_script" = x; then
+        tag_sed_script="$1"
+      else
+        echo "$0: extra non-option argument '$1'." >&2
+        exit 1
+      fi;;
+  esac
+  shift
+done
+
+if test "x$tarball_version_file" = x; then
+    echo "$usage"
+    exit 1
+fi
+
+tag_sed_script="${tag_sed_script:-s/x/x/}"
+
+nl='
+'
+
+# Avoid meddling by environment variable of the same name.
+v=
+v_from_git=
+
+# First see if there is a tarball-only version file.
+# then try "git describe", then default.
+if test -f $tarball_version_file
+then
+    v=`cat $tarball_version_file` || v=
+    case $v in
+        *$nl*) v= ;; # reject multi-line output
+        [0-9]*) ;;
+        *) v= ;;
+    esac
+    test "x$v" = x \
+        && echo "$0: WARNING: $tarball_version_file is missing or damaged" 1>&2
+fi
+
+if test "x$v" != x
+then
+    : # use $v
+# Otherwise, if there is at least one git commit involving the working
+# directory, and "git describe" output looks sensible, use that to
+# derive a version string.
+elif test "`git log -1 --pretty=format:x . 2>&1`" = x \
+    && v=`git describe --abbrev=4 --match="$prefix*" HEAD 2>/dev/null \
+          || git describe --abbrev=4 HEAD 2>/dev/null` \
+    && v=`printf '%s\n' "$v" | sed "$tag_sed_script"` \
+    && case $v in
+         $prefix[0-9]*) ;;
+         *) (exit 1) ;;
+       esac
+then
+    # Is this a new git that lists number of commits since the last
+    # tag or the previous older version that did not?
+    #   Newer: v6.10-77-g0f8faeb
+    #   Older: v6.10-g0f8faeb
+    case $v in
+        *-*-*) : git describe is okay three part flavor ;;
+        *-*)
+            : git describe is older two part flavor
+            # Recreate the number of commits and rewrite such that the
+            # result is the same as if we were using the newer version
+            # of git describe.
+            vtag=`echo "$v" | sed 's/-.*//'`
+            commit_list=`git rev-list "$vtag"..HEAD 2>/dev/null` \
+                || { commit_list=failed;
+                     echo "$0: WARNING: git rev-list failed" 1>&2; }
+            numcommits=`echo "$commit_list" | wc -l`
+            v=`echo "$v" | sed "s/\(.*\)-\(.*\)/\1-$numcommits-\2/"`;
+            test "$commit_list" = failed && v=UNKNOWN
+            ;;
+    esac
+
+    # Change the first '-' to a '.', so version-comparing tools work properly.
+    # Remove the "g" in git describe's output string, to save a byte.
+    v=`echo "$v" | sed 's/-/./;s/\(.*\)-g/\1-/'`;
+    v_from_git=1
+elif test "x$fallback" = x || git --version >/dev/null 2>&1; then
+    v=UNKNOWN
+else
+    v=$fallback
+fi
+
+v=`echo "$v" |sed "s/^$prefix//"`
+
+# Test whether to append the "-dirty" suffix only if the version
+# string we're using came from git.  I.e., skip the test if it's "UNKNOWN"
+# or if it came from .tarball-version.
+if test "x$v_from_git" != x; then
+  # Don't declare a version "dirty" merely because a timestamp has changed.
+  git update-index --refresh > /dev/null 2>&1
+
+  dirty=`exec 2>/dev/null;git diff-index --name-only HEAD` || dirty=
+  case "$dirty" in
+      '') ;;
+      *) # Append the suffix only if there isn't one already.
+          case $v in
+            *-dirty) ;;
+            *) v="$v-dirty" ;;
+          esac ;;
+  esac
+fi
+
+# Omit the trailing newline, so that m4_esyscmd can use the result directly.
+printf %s "$v"
+
+# Local variables:
+# eval: (add-hook 'write-file-hooks 'time-stamp)
+# time-stamp-start: "scriptversion="
+# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-time-zone: "UTC0"
+# time-stamp-end: "; # UTC"
+# End:
diff --git a/build-aux/hydra/evaluate.scm b/build-aux/hydra/evaluate.scm
index ab10253f31..cc6a4b9492 100644
--- a/build-aux/hydra/evaluate.scm
+++ b/build-aux/hydra/evaluate.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2016 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2016, 2017 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -32,6 +32,13 @@
     (beautify-user-module! m)
     m))
 
+(cond-expand
+  (guile-2.2
+   ;; Guile 2.2.2 has a bug whereby 'time-monotonic' objects have seconds and
+   ;; nanoseconds swapped (fixed in Guile commit 886ac3e).  Work around it.
+   (define time-monotonic time-tai))
+  (else #t))
+
 (define (call-with-time thunk kont)
   "Call THUNK and pass KONT the elapsed time followed by THUNK's return
 values."
diff --git a/build-aux/hydra/gnu-system.scm b/build-aux/hydra/gnu-system.scm
index 507c6abe0e..b1faa2265a 100644
--- a/build-aux/hydra/gnu-system.scm
+++ b/build-aux/hydra/gnu-system.scm
@@ -111,7 +111,7 @@ SYSTEM."
   ;; chain.)
   (list gcc-4.8 gcc-4.9 gcc-5 glibc binutils
         gmp mpfr mpc coreutils findutils diffutils patch sed grep
-        gawk gnu-gettext hello guile-2.0 zlib gzip xz
+        gawk gnu-gettext hello guile-2.0 guile-2.2 zlib gzip xz
         %bootstrap-binaries-tarball
         %binutils-bootstrap-tarball
         (%glibc-bootstrap-tarball)
diff --git a/build-aux/update-NEWS.scm b/build-aux/update-NEWS.scm
new file mode 100644
index 0000000000..2e8f68c9a8
--- /dev/null
+++ b/build-aux/update-NEWS.scm
@@ -0,0 +1,161 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2017 Ludovic Courtès <ludo@gnu.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/>.
+
+;;; Commentary:
+;;;
+;;; This script updates the list of new and updated packages in 'NEWS'.
+;;;
+;;; Code:
+
+(use-modules (gnu) (guix)
+             (guix build utils)
+             ((guix ui) #:select (fill-paragraph))
+             (srfi srfi-1)
+             (srfi srfi-11)
+             (ice-9 match)
+             (ice-9 rdelim)
+             (ice-9 regex)
+             (ice-9 pretty-print))
+
+(define %header-rx
+  (make-regexp "^\\* Changes in (version )?([0-9.]+) \\(since ([0-9.]+)\\)"))
+
+(define (NEWS->versions port)
+  "Return two values: the previous version and the current version as read
+from PORT, which is an input port on the 'NEWS' file."
+  (let loop ()
+    (let ((line (read-line port)))
+      (cond ((eof-object? line)
+             (error "failed to determine previous and current version"
+                    port))
+            ((regexp-exec %header-rx line)
+             =>
+             (lambda (match)
+               (values (match:substring match 3)
+                       (match:substring match 2))))
+            (else
+             (loop))))))
+
+(define (skip-to-org-heading port)
+  "Read from PORT until an Org heading is found."
+  (let loop ()
+    (let ((next (peek-char port)))
+      (cond ((eqv? next #\*)
+             #t)
+            ((eof-object? next)
+             (error "next heading could not be found"))
+            (else
+             (read-line port)
+             (loop))))))
+
+(define (rewrite-org-section input output heading-rx proc)
+  "Write to OUTPUT the text read from INPUT, but with the first Org section
+matching HEADING-RX replaced by NEW-HEADING and CONTENTS."
+  (let loop ()
+    (let ((line (read-line input)))
+      (cond ((eof-object? line)
+             (error "failed to match heading regexp" heading-rx))
+            ((regexp-exec heading-rx line)
+             =>
+             (lambda (match)
+               (proc match output)
+               (skip-to-org-heading input)
+               (dump-port input output)
+               #t))
+            (else
+             (display line output)
+             (newline output)
+             (loop))))))
+
+(define (enumeration->paragraph lst)
+  "Turn LST, a list of strings, into a single string that is a ready-to-print
+paragraph."
+  (fill-paragraph (string-join (sort lst string<?) ", ")
+                  75))
+
+(define (write-packages-added news-file old new)
+  "Write to NEWS-FILE the list of packages added between OLD and NEW."
+  (let ((added (lset-difference string=? (map car new) (map car old))))
+    (with-atomic-file-replacement news-file
+      (lambda (input output)
+        (rewrite-org-section input output
+                             (make-regexp "^(\\*+) (.*) new packages")
+                             (lambda (match port)
+                               (let ((stars (match:substring match 1)))
+                                 (format port
+                                         "~a ~a new packages~%~%~a~%~%"
+                                         stars (length added)
+                                         (enumeration->paragraph added)))))))))
+
+(define (write-packages-updates news-file old new)
+  "Write to NEWS-FILE the list of packages upgraded between OLD and NEW."
+  (let ((upgraded (filter-map (match-lambda
+                                ((package . new-version)
+                                 (match (assoc package old)
+                                   ((_ . old-version)
+                                    (and (version>? new-version old-version)
+                                         (string-append package "@"
+                                                        new-version)))
+                                   (_ #f))))
+                              new)))
+    (with-atomic-file-replacement news-file
+      (lambda (input output)
+        (rewrite-org-section input output
+                             (make-regexp "^(\\*+) (.*) package updates")
+                             (lambda (match port)
+                               (let ((stars (match:substring match 1)))
+                                 (format port
+                                         "~a ~a package updates~%~%~a~%~%"
+                                         stars (length upgraded)
+                                         (enumeration->paragraph upgraded)))))))))
+
+
+(define (main . args)
+  (match args
+    ((news-file data-directory)
+     ;; Don't browse things listed in the user's $GUIX_PACKAGE_PATH.  Here we
+     ;; assume that the last item in (%package-module-path) is the distro
+     ;; directory.
+     (parameterize ((%package-module-path
+                     (list (last (%package-module-path)))))
+       (define (package-file version)
+         (string-append data-directory "/packages-"
+                        version ".txt"))
+
+       (let-values (((previous-version new-version)
+                     (call-with-input-file news-file NEWS->versions)))
+         (let* ((old (call-with-input-file (package-file previous-version)
+                       read))
+                (new (fold-packages (lambda (p r)
+                                      (alist-cons (package-name p) (package-version p)
+                                                  r))
+                                    '())))
+           (call-with-output-file (package-file new-version)
+             (lambda (port)
+               (pretty-print new port)))
+
+           (write-packages-added news-file old new)
+           (write-packages-updates news-file old new)))))
+    (x
+     (format (current-error-port) "Usage: update-NEWS NEWS-FILE DATA-DIRECTORY
+
+Update the list of new and updated packages in NEWS-FILE using the
+previous-version package list from DATA-DIRECTORY.\n")
+     (exit 1))))
+
+(apply main (cdr (command-line)))
diff --git a/build-aux/update-guix-package.scm b/build-aux/update-guix-package.scm
new file mode 100644
index 0000000000..9598872dfd
--- /dev/null
+++ b/build-aux/update-guix-package.scm
@@ -0,0 +1,144 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2017 Ludovic Courtès <ludo@gnu.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/>.
+
+;;; Commentary:
+;;;
+;;; This scripts updates the definition of the 'guix' package in Guix for the
+;;; current commit.  It requires Git to be installed.
+;;;
+;;; Code:
+
+(use-modules (guix)
+             (guix git-download)
+             (guix upstream)
+             (guix utils)
+             (guix base32)
+             (guix build utils)
+             (gnu packages package-management)
+             (ice-9 match))
+
+(define %top-srcdir
+  (string-append (current-source-directory) "/.."))
+
+(define version-controlled?
+  (git-predicate %top-srcdir))
+
+(define (package-definition-location)
+  "Return the source properties of the definition of the 'guix' package."
+  (call-with-input-file (location-file (package-location guix))
+    (lambda (port)
+      (let loop ()
+        (match (read port)
+          ((? eof-object?)
+           (error "definition of 'guix' package could not be found"
+                  (port-filename port)))
+          (('define-public 'guix value)
+           (source-properties value))
+          (_
+           (loop)))))))
+
+(define* (update-definition commit hash
+                            #:key version old-hash)
+  "Return a one-argument procedure that takes a string, the definition of the
+'guix' package, and returns a string, the update definition for VERSION,
+COMMIT."
+  (define (linear-offset str line column)
+    ;; Return the offset in characters to reach LINE and COLUMN (both
+    ;; zero-indexed) in STR.
+    (call-with-input-string str
+      (lambda (port)
+        (let loop ((offset 0))
+          (cond ((and (= (port-column port) column)
+                      (= (port-line port) line))
+                 offset)
+                ((eof-object? (read-char port))
+                 (error "line and column not reached!"
+                        str))
+                (else
+                 (loop (+ 1 offset))))))))
+
+  (define (update-hash str)
+    ;; Replace OLD-HASH with HASH in STR.
+    (string-replace-substring str
+                              (bytevector->nix-base32-string old-hash)
+                              (bytevector->nix-base32-string hash)))
+
+  (lambda (str)
+    (match (call-with-input-string str read)
+      (('let (('version old-version)
+              ('commit old-commit)
+              ('revision old-revision))
+         defn)
+       (let* ((location (source-properties defn))
+              (line     (assq-ref location 'line))
+              (column   0)
+              (offset   (linear-offset str line column)))
+         (string-append (format #f "(let ((version \"~a\")
+        (commit \"~a\")
+        (revision ~a))\n"
+                                (or version old-version)
+                                commit
+                                (if (and version
+                                         (not (string=? version old-version)))
+                                    0
+                                    (+ 1 old-revision)))
+                        (string-drop (update-hash str) offset))))
+      (exp
+       (error "'guix' package definition is not as expected" exp)))))
+
+
+(define (main . args)
+  (match args
+    ((commit version)
+     (with-store store
+       (let* ((source   (add-to-store store
+                                      "guix-checkout" ;dummy name
+                                      #t "sha256" %top-srcdir
+                                      #:select? version-controlled?))
+              (hash     (query-path-hash store source))
+              (location (package-definition-location))
+              (old-hash (origin-sha256 (package-source guix))))
+         (edit-expression location
+                          (update-definition commit hash
+                                             #:old-hash old-hash
+                                             #:version version))
+
+         ;; Re-add SOURCE to the store, but this time under the real name used
+         ;; in the 'origin'.  This allows us to build the package without
+         ;; having to make a real checkout; thus, it also works when working
+         ;; on a private branch.
+         (reload-module
+          (resolve-module '(gnu packages package-management)))
+
+         (let* ((source (add-to-store store
+                                      (origin-file-name (package-source guix))
+                                      #t "sha256" source))
+                (root   (store-path-package-name source)))
+
+           ;; Add an indirect GC root for SOURCE in the current directory.
+           (false-if-exception (delete-file root))
+           (symlink source root)
+           (add-indirect-root store root)
+
+           (format #t "source code for commit ~a: ~a (GC root: ~a)~%"
+                   commit source root)))))
+    ((commit)
+     ;; Automatically deduce the version and revision numbers.
+     (main commit #f))))
+
+(apply main (cdr (command-line)))