Merge branch 'master' into core-updates

22 files changed, 546 insertions, 212 deletions

diff --git a/guix/build-system/go.scm b/guix/build-system/go.scm
index ec447d2a28..cf91163275 100644
--- a/guix/build-system/go.scm
+++ b/guix/build-system/go.scm
@@ -82,6 +82,7 @@
                    (import-path "")
                    (unpack-path "")
                    (tests? #t)
+                   (allow-go-reference? #f)
                    (system (%current-system))
                    (guile #f)
                    (imported-modules %go-build-system-modules)
@@ -107,6 +108,7 @@
                 #:import-path ,import-path
                 #:unpack-path ,unpack-path
                 #:tests? ,tests?
+                #:allow-go-reference? ,allow-go-reference?
                 #:inputs %build-inputs)))
 
   (define guile-for-build
diff --git a/guix/build-system/r.scm b/guix/build-system/r.scm
index 2c8a89f8de..6bdb7061eb 100644
--- a/guix/build-system/r.scm
+++ b/guix/build-system/r.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2015 Ricardo Wurmus <rekado@elephly.net>
+;;; Copyright © 2015, 2017 Ricardo Wurmus <rekado@elephly.net>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -50,8 +50,11 @@ available via the first URI, the second URI points to the archived version."
 (define (bioconductor-uri name version)
   "Return a URI string for the R package archive on Bioconductor for the
 release corresponding to NAME and VERSION."
-  (string-append "https://bioconductor.org/packages/release/bioc/src/contrib/"
-                 name "_" version ".tar.gz"))
+  (list (string-append "https://bioconductor.org/packages/release/bioc/src/contrib/"
+                       name "_" version ".tar.gz")
+        ;; TODO: use %bioconductor-version from (guix import cran)
+        (string-append "https://bioconductor.org/packages/3.6/bioc/src/contrib/Archive/"
+                       name "_" version ".tar.gz")))
 
 (define %r-build-system-modules
   ;; Build-side modules imported by default.
diff --git a/guix/build/compile.scm b/guix/build/compile.scm
index ea0c36fa33..8b5a2faf84 100644
--- a/guix/build/compile.scm
+++ b/guix/build/compile.scm
@@ -77,6 +77,12 @@
   "Strip the \".scm\" suffix from FILE, and append \".go\"."
   (string-append (string-drop-right file 4) ".go"))
 
+(define (relative-file directory file)
+  "Return FILE relative to DIRECTORY, if possible."
+  (if (string-prefix? (string-append directory "/") file)
+      (string-drop file (+ 1 (string-length directory)))
+      file))
+
 (define* (load-files directory files
                      #:key
                      (report-load (const #f))
@@ -93,13 +99,14 @@
          (report-load #f total completed))
        *unspecified*)
       ((file files ...)
-       (report-load file total completed)
-       (format debug-port "~%loading '~a'...~%" file)
+       (let ((file (relative-file directory file)))
+         (report-load file total completed)
+         (format debug-port "~%loading '~a'...~%" file)
 
-       (parameterize ((current-warning-port debug-port))
-         (resolve-interface (file-name->module-name file)))
+         (parameterize ((current-warning-port debug-port))
+           (resolve-interface (file-name->module-name file)))
 
-       (loop files (+ 1 completed))))))
+         (loop files (+ 1 completed)))))))
 
 (define-syntax-rule (with-augmented-search-path path item body ...)
   "Within the dynamic extent of BODY, augment PATH by adding ITEM to the
@@ -135,11 +142,12 @@ files are for HOST, a GNU triplet such as \"x86_64-linux-gnu\"."
     (with-fluids ((*current-warning-prefix* ""))
       (with-target host
         (lambda ()
-          (compile-file file
-                        #:output-file (string-append build-directory "/"
-                                                     (scm->go file))
-                        #:opts (append warning-options
-                                       (optimization-options file))))))
+          (let ((relative (relative-file source-directory file)))
+            (compile-file file
+                          #:output-file (string-append build-directory "/"
+                                                       (scm->go relative))
+                          #:opts (append warning-options
+                                         (optimization-options relative)))))))
     (with-mutex progress-lock
       (set! completed (+ 1 completed))))
 
diff --git a/guix/build/download.scm b/guix/build/download.scm
index 61c9c6d3f1..4490d225e6 100644
--- a/guix/build/download.scm
+++ b/guix/build/download.scm
@@ -130,7 +130,8 @@ out if the connection could not be established in less than TIMEOUT seconds."
                  (_ (ftp-open (uri-host uri) #:timeout timeout))))
          (size (false-if-exception (ftp-size conn (uri-path uri))))
          (in   (ftp-retr conn (basename (uri-path uri))
-                         (dirname (uri-path uri)))))
+                         (dirname (uri-path uri))
+                         #:timeout timeout)))
     (call-with-output-file file
       (lambda (out)
         (dump-port* in out
@@ -305,6 +306,13 @@ host name without trailing dot."
       ;; never be closed.  So we use `fileno', but keep a weak reference to
       ;; PORT, so the file descriptor gets closed when RECORD is GC'd.
       (register-tls-record-port record port)
+
+      ;; Write HTTP requests line by line rather than byte by byte:
+      ;; <https://bugs.gnu.org/22966>.  This is not possible on Guile 2.0.
+      (cond-expand
+        (guile-2.0 #f)
+        (else (setvbuf record 'line)))
+
       record)))
 
 (define (ensure-uri uri-or-string)                ;XXX: copied from (web http)
@@ -513,6 +521,57 @@ port if PORT is a TLS session record port."
       (let ((declare-relative-uri-header! (variable-ref var)))
         (declare-relative-uri-header! "Location")))))
 
+;; XXX: Work around broken proxy handling on Guile 2.2 <= 2.2.2, fixed in
+;; Guile commits 7d0d9e2c25c1e872cfc7d14ab5139915f1813d56 and
+;; 6ad28ae3bc6a6d9e95ab7d70510d12c97673a143.  See bug report at
+;; <https://lists.gnu.org/archive/html/guix-devel/2017-11/msg00070.html>.
+(cond-expand
+  (guile-2.2
+   (when (<= (string->number (micro-version)) 2)
+     (let ()
+       (define put-symbol (@@ (web http) put-symbol))
+       (define put-non-negative-integer
+         (@@ (web http) put-non-negative-integer))
+       (define write-http-version
+         (@@ (web http) write-http-version))
+
+       (define (write-request-line method uri version port)
+         "Write the first line of an HTTP request to PORT."
+         (put-symbol port method)
+         (put-char port #\space)
+         (when (http-proxy-port? port)
+           (let ((scheme (uri-scheme uri))
+                 (host (uri-host uri))
+                 (host-port (uri-port uri)))
+             (when (and scheme host)
+               (put-symbol port scheme)
+               (put-string port "://")
+               (cond
+                ((string-index host #\:)          ;<---- The fix is here!
+                 (put-char port #\[)              ;<---- And here!
+                 (put-string port host)
+                 (put-char port #\]))
+                (else
+                 (put-string port host)))
+               (unless ((@@ (web uri) default-port?) scheme host-port)
+                 (put-char port #\:)
+                 (put-non-negative-integer port host-port)))))
+         (let ((path (uri-path uri))
+               (query (uri-query uri)))
+           (if (string-null? path)
+               (put-string port "/")
+               (put-string port path))
+           (when query
+             (put-string port "?")
+             (put-string port query)))
+         (put-char port #\space)
+         (write-http-version version port)
+         (put-string port "\r\n"))
+
+       (module-set! (resolve-module '(web http)) 'write-request-line
+                    write-request-line))))
+  (else #t))
+
 (define (resolve-uri-reference ref base)
   "Resolve the URI reference REF, interpreted relative to the BASE URI, into a
 target URI, according to the algorithm specified in RFC 3986 section 5.2.2.
diff --git a/guix/build/go-build-system.scm b/guix/build/go-build-system.scm
index d175f3b76a..eaad9d8751 100644
--- a/guix/build/go-build-system.scm
+++ b/guix/build/go-build-system.scm
@@ -22,6 +22,8 @@
   #:use-module (guix build utils)
   #:use-module (ice-9 match)
   #:use-module (srfi srfi-1)
+  #:use-module (rnrs io ports)
+  #:use-module (rnrs bytevectors)
   #:export (%standard-phases
             go-build))
 
@@ -197,13 +199,66 @@ respectively."
 
 (define* (install #:key outputs #:allow-other-keys)
   "Install the compiled libraries. `go install` installs these files to
-$GOPATH/pkg, so we have to copy them into the output direcotry manually.
+$GOPATH/pkg, so we have to copy them into the output directory manually.
 Compiled executable files should have already been installed to the store based
 on $GOBIN in the build phase."
   (when (file-exists? "pkg")
     (copy-recursively "pkg" (string-append (assoc-ref outputs "out") "/pkg")))
   #t)
 
+(define* (remove-store-reference file file-name
+                                  #:optional (store (%store-directory)))
+  "Remove from FILE occurrences of FILE-NAME in STORE; return #t when FILE-NAME
+is encountered in FILE, #f otherwise. This implementation reads FILE one byte at
+a time, which is slow. Instead, we should use the Boyer-Moore string search
+algorithm; there is an example in (guix build grafts)."
+  (define pattern
+    (string-take file-name
+                 (+ 34 (string-length (%store-directory)))))
+
+  (with-fluids ((%default-port-encoding #f))
+    (with-atomic-file-replacement file
+      (lambda (in out)
+        ;; We cannot use `regexp-exec' here because it cannot deal with
+        ;; strings containing NUL characters.
+        (format #t "removing references to `~a' from `~a'...~%" file-name file)
+        (setvbuf in 'block 65536)
+        (setvbuf out 'block 65536)
+        (fold-port-matches (lambda (match result)
+                             (put-bytevector out (string->utf8 store))
+                             (put-u8 out (char->integer #\/))
+                             (put-bytevector out
+                                             (string->utf8
+                                              "eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-"))
+                             #t)
+                           #f
+                           pattern
+                           in
+                           (lambda (char result)
+                             (put-u8 out (char->integer char))
+                             result))))))
+
+(define* (remove-go-references #:key allow-go-reference?
+                               inputs outputs #:allow-other-keys)
+  "Remove any references to the Go compiler from the compiled Go executable
+files in OUTPUTS."
+;; We remove this spurious reference to save bandwidth when installing Go
+;; executables. It would be better to not embed the reference in the first
+;; place, but I'm not sure how to do that. The subject was discussed at:
+;; <https://lists.gnu.org/archive/html/guix-devel/2017-10/msg00207.html>
+  (if allow-go-reference?
+    #t
+    (let ((go (assoc-ref inputs "go"))
+          (bin "/bin"))
+      (for-each (lambda (output)
+                  (when (file-exists? (string-append (cdr output)
+                                                     bin))
+                    (for-each (lambda (file)
+                                (remove-store-reference file go))
+                              (find-files (string-append (cdr output) bin)))))
+                outputs)
+      #t)))
+
 (define %standard-phases
   (modify-phases gnu:%standard-phases
     (delete 'configure)
@@ -213,7 +268,8 @@ on $GOBIN in the build phase."
     (add-before 'build 'setup-environment setup-environment)
     (replace 'build build)
     (replace 'check check)
-    (replace 'install install)))
+    (replace 'install install)
+    (add-after 'install 'remove-go-references remove-go-references)))
 
 (define* (go-build #:key inputs (phases %standard-phases)
                       #:allow-other-keys #:rest args)
diff --git a/guix/build/graft.scm b/guix/build/graft.scm
index 3dce486adf..e567bff4f4 100644
--- a/guix/build/graft.scm
+++ b/guix/build/graft.scm
@@ -214,6 +214,7 @@ an exception is caught."
           (print-exception port #f key args)
           (primitive-exit 1))))))
 
+;; We need this as long as we support Guile < 2.0.13.
 (define* (mkdir-p* dir #:optional (mode #o755))
   "This is a variant of 'mkdir-p' that works around
 <http://bugs.gnu.org/24659> by passing MODE explicitly in each 'mkdir' call."
diff --git a/guix/build/pull.scm b/guix/build/pull.scm
index 3573241a7e..a011e366f6 100644
--- a/guix/build/pull.scm
+++ b/guix/build/pull.scm
@@ -121,41 +121,32 @@ containing the source code.  Write any debugging output to DEBUG-PORT."
 
     ;; Compile the .scm files.  Hide warnings.
     (parameterize ((current-warning-port (%make-void-port "w")))
-      (with-directory-excursion out
-        ;; Filter out files depending on Guile-SSH when Guile-SSH is missing.
-        (let ((files (filter has-all-its-dependencies?
-                             (all-scheme-files "."))))
-          (compile-files out out
-
-                         ;; XXX: 'compile-files' except ready-to-use relative
-                         ;; file names.
-                         (map (lambda (file)
-                                (if (string-prefix? "./" file)
-                                    (string-drop file 2)
-                                    file))
-                              files)
-
-                         #:workers (parallel-job-count)
-
-                         ;; Disable warnings.
-                         #:warning-options '()
-
-                         #:report-load
-                         (lambda (file total completed)
-                           (display #\cr log-port)
-                           (format log-port
-                                   "loading...\t~5,1f% of ~d files" ;FIXME: i18n
-                                   (* 100. (/ completed total)) total)
-                           (force-output log-port)
-                           (format debug-port "~%loading '~a'...~%" file))
-
-                         #:report-compilation
-                         (lambda (file total completed)
-                           (display #\cr log-port)
-                           (format log-port "compiling...\t~5,1f% of ~d files" ;FIXME: i18n
-                                   (* 100. (/ completed total)) total)
-                           (force-output log-port)
-                           (format debug-port "~%compiling '~a'...~%" file)))))))
+      ;; Filter out files depending on Guile-SSH when Guile-SSH is missing.
+      (let ((files (filter has-all-its-dependencies?
+                           (all-scheme-files out))))
+        (compile-files out out files
+
+                       #:workers (parallel-job-count)
+
+                       ;; Disable warnings.
+                       #:warning-options '()
+
+                       #:report-load
+                       (lambda (file total completed)
+                         (display #\cr log-port)
+                         (format log-port
+                                 "loading...\t~5,1f% of ~d files" ;FIXME: i18n
+                                 (* 100. (/ completed total)) total)
+                         (force-output log-port)
+                         (format debug-port "~%loading '~a'...~%" file))
+
+                       #:report-compilation
+                       (lambda (file total completed)
+                         (display #\cr log-port)
+                         (format log-port "compiling...\t~5,1f% of ~d files" ;FIXME: i18n
+                                 (* 100. (/ completed total)) total)
+                         (force-output log-port)
+                         (format debug-port "~%compiling '~a'...~%" file))))))
 
   (newline)
   #t)
diff --git a/guix/build/texlive-build-system.scm b/guix/build/texlive-build-system.scm
index c0f262a5c0..f6b9b96b87 100644
--- a/guix/build/texlive-build-system.scm
+++ b/guix/build/texlive-build-system.scm
@@ -46,7 +46,7 @@
     ;; Build a modifiable union of all inputs (but exclude bash)
     (match inputs
       (((names . directories) ...)
-       (union-build out directories
+       (union-build out (filter directory-exists? directories)
                     #:create-all-directories? #t
                     #:log-port (%make-void-port "w"))))
 
diff --git a/guix/cve.scm b/guix/cve.scm
index 38e59944c8..070acfeb3e 100644
--- a/guix/cve.scm
+++ b/guix/cve.scm
@@ -19,7 +19,6 @@
 (define-module (guix cve)
   #:use-module (guix utils)
   #:use-module (guix http-client)
-  #:use-module ((guix build utils) #:select (mkdir-p))
   #:use-module (sxml ssax)
   #:use-module (web uri)
   #:use-module (srfi srfi-1)
@@ -68,24 +67,11 @@
 (define %current-year-ttl
   ;; According to <https://nvd.nist.gov/download.cfm#CVE_FEED>, feeds are
   ;; updated "approximately every two hours."
-  (* 3600 3))
+  (* 60 30))
 
 (define %past-year-ttl
   ;; Update the previous year's database more and more infrequently.
-  (* 3600 24 2 (date-month %now)))
-
-(define (call-with-cve-port uri ttl proc)
-  "Pass PROC an input port from which to read the CVE stream."
-  (let ((port (http-fetch uri)))
-    (dynamic-wind
-      (const #t)
-      (lambda ()
-        (call-with-decompressed-port 'gzip port
-          (lambda (port)
-            (setvbuf port _IOFBF 65536)
-            (proc port))))
-      (lambda ()
-        (close-port port)))))
+  (* 3600 24 (date-month %now)))
 
 (define %cpe-package-rx
   ;; For applications: "cpe:/a:VENDOR:PACKAGE:VERSION", or sometimes
@@ -194,40 +180,27 @@ vulnerability objects."
     (('v id (packages ...))
      (vulnerability id packages))))
 
-(define (fetch-vulnerabilities year ttl)
-  "Return the list of <vulnerability> for YEAR, assuming the on-disk cache has
-the given TTL (fetch from the NIST web site when TTL has expired)."
-  ;; Note: We used to keep the original XML files in cache but parsing it
-  ;; would take typically ~15s for a year of data.  Thus, we instead store a
-  ;; summarized version thereof as an sexp, which can be parsed in 1s or so.
-  (define cache
-    (string-append (cache-directory) "/cve/" (number->string year)))
-
-  (define (do-fetch)
-    (call-with-cve-port (yearly-feed-uri year) ttl
-      (lambda (port)
-        ;; XXX: The SSAX "error port" is used to send pointless warnings such as
-        ;; "warning: Skipping PI".  Turn that off.
-        (format (current-error-port) "fetching CVE database for ~a...~%" year)
+(define (write-cache input cache)
+  "Read vulnerabilities as gzipped XML from INPUT, and write it as a compact
+sexp to CACHE."
+  (call-with-decompressed-port 'gzip input
+    (lambda (input)
+      ;; XXX: The SSAX "error port" is used to send pointless warnings such as
+      ;; "warning: Skipping PI".  Turn that off.
+      (define vulns
         (parameterize ((current-ssax-error-port (%make-void-port "w")))
-          (xml->vulnerabilities port)))))
+          (xml->vulnerabilities input)))
 
-  (define (update-cache)
-    (mkdir-p (dirname cache))
-    (let ((vulns (do-fetch)))
-      (with-atomic-file-output cache
-        (lambda (port)
-          (write `(vulnerabilities
-                   1                              ;format version
-                   ,(map vulnerability->sexp vulns))
-                 port)))
-      vulns))
+      (write `(vulnerabilities
+               1                                  ;format version
+               ,(map vulnerability->sexp vulns))
+             cache))))
 
-  (define (old? file)
-    ;; Return true if PORT has passed TTL.
-    (let* ((s   (stat file))
-           (now (current-time time-utc)))
-      (< (+ (stat:mtime s) ttl) (time-second now))))
+(define (fetch-vulnerabilities year ttl)
+  "Return the list of <vulnerability> for YEAR, assuming the on-disk cache has
+the given TTL (fetch from the NIST web site when TTL has expired)."
+  (define (cache-miss uri)
+    (format (current-error-port) "fetching CVE database for ~a...~%" year))
 
   (define (read* port)
     ;; Disable read options to avoid populating the source property weak
@@ -242,17 +215,18 @@ the given TTL (fetch from the NIST web site when TTL has expired)."
         (lambda ()
           (read-options options)))))
 
-  (catch 'system-error
-    (lambda ()
-      (if (old? cache)
-          (update-cache)
-          (match (call-with-input-file cache read*)
-            (('vulnerabilities 1 vulns)
-             (map sexp->vulnerability vulns))
-            (x
-             (update-cache)))))
-    (lambda args
-      (update-cache))))
+  ;; Note: We used to keep the original XML files in cache but parsing it
+  ;; would take typically ~15s for a year of data.  Thus, we instead store a
+  ;; summarized version thereof as an sexp, which can be parsed in 1s or so.
+  (let* ((port (http-fetch/cached (yearly-feed-uri year)
+                                  #:ttl ttl
+                                  #:write-cache write-cache
+                                  #:cache-miss cache-miss))
+         (sexp (read* port)))
+    (close-port port)
+    (match sexp
+      (('vulnerabilities 1 vulns)
+       (map sexp->vulnerability vulns)))))
 
 (define (current-vulnerabilities)
   "Return the current list of Common Vulnerabilities and Exposures (CVE) as
@@ -307,8 +281,4 @@ vulnerabilities affecting the given package version."
                  package table)))
 
 
-;;; Local Variables:
-;;; eval: (put 'call-with-cve-port 'scheme-indent-function 2)
-;;; End:
-
 ;;; cve.scm ends here
diff --git a/guix/download.scm b/guix/download.scm
index 1bd4875b10..55da2c1d37 100644
--- a/guix/download.scm
+++ b/guix/download.scm
@@ -95,17 +95,17 @@
        "http://hackage.haskell.org/")
       (savannah
        "http://download.savannah.gnu.org/releases/"
-       "ftp://ftp.twaren.net/Unix/NonGNU/"
-       "ftp://mirror.csclub.uwaterloo.ca/nongnu/"
-       "ftp://mirror.publicns.net/pub/nongnu/"
-       "ftp://savannah.c3sl.ufpr.br/"
        "http://ftp.cc.uoc.gr/mirrors/nongnu.org/"
        "http://ftp.twaren.net/Unix/NonGNU/"
        "http://mirror.csclub.uwaterloo.ca/nongnu/"
        "http://nongnu.askapache.com/"
        "http://savannah.c3sl.ufpr.br/"
        "http://download.savannah.gnu.org/releases-noredirect/"
-       "http://download-mirror.savannah.gnu.org/releases/")
+       "http://download-mirror.savannah.gnu.org/releases/"
+       "ftp://ftp.twaren.net/Unix/NonGNU/"
+       "ftp://mirror.csclub.uwaterloo.ca/nongnu/"
+       "ftp://mirror.publicns.net/pub/nongnu/"
+       "ftp://savannah.c3sl.ufpr.br/")
       (sourceforge ; https://sourceforge.net/p/forge/documentation/Mirrors/
        "http://downloads.sourceforge.net/project/"
        "http://ufpr.dl.sourceforge.net/project/"
@@ -134,26 +134,26 @@
        "http://ramses.wh2.tu-dresden.de/pub/mirrors/kernel.org/"
        "http://linux-kernel.uio.no/pub/"
        "http://kernel.osuosl.org/pub/"
-       "ftp://ftp.funet.fi/pub/mirrors/ftp.kernel.org/pub/"
        "http://ftp.be.debian.org/pub/"
-       "http://mirror.linux.org.au/")
+       "http://mirror.linux.org.au/"
+       "ftp://ftp.funet.fi/pub/mirrors/ftp.kernel.org/pub/")
       (apache             ; from http://www.apache.org/mirrors/dist.html
        "http://www.eu.apache.org/dist/"
        "http://www.us.apache.org/dist/"
-       "ftp://gd.tuwien.ac.at/pub/infosys/servers/http/apache/dist/"
        "http://apache.belnet.be/"
        "http://mirrors.ircam.fr/pub/apache/"
        "http://apache-mirror.rbc.ru/pub/apache/"
+       "ftp://gd.tuwien.ac.at/pub/infosys/servers/http/apache/dist/"
 
        ;; As a last resort, try the archive.
        "http://archive.apache.org/dist/")
       (xorg               ; from http://www.x.org/wiki/Releases/Download
        "http://www.x.org/releases/" ; main mirrors
-       "ftp://mirror.csclub.uwaterloo.ca/x.org/" ; North America
-       "ftp://xorg.mirrors.pair.com/"
-       "http://mirror.csclub.uwaterloo.ca/x.org/"
+       "http://mirror.csclub.uwaterloo.ca/x.org/" ; North America
        "http://xorg.mirrors.pair.com/"
        "http://mirror.us.leaseweb.net/xorg/"
+       "ftp://mirror.csclub.uwaterloo.ca/x.org/"
+       "ftp://xorg.mirrors.pair.com/"
        "ftp://artfiles.org/x.org/" ; Europe
        "ftp://ftp.chg.ru/pub/X11/x.org/"
        "ftp://ftp.fu-berlin.de/unix/X11/FTP.X.ORG/"
@@ -169,12 +169,12 @@
        "ftp://mirror.switch.ch/mirror/X11/"
        "ftp://mirrors.ircam.fr/pub/x.org/"
        "ftp://x.mirrors.skynet.be/pub/ftp.x.org/"
-       "ftp://ftp.cs.cuhk.edu.hk/pub/X11" ; East Asia
+       "http://x.cs.pu.edu.tw/" ; East Asia
+       "ftp://ftp.cs.cuhk.edu.hk/pub/X11"
        "ftp://ftp.u-aizu.ac.jp/pub/x11/x.org/"
        "ftp://ftp.yz.yamagata-u.ac.jp/pub/X11/x.org/"
        "ftp://ftp.kaist.ac.kr/x.org/"
        "ftp://mirrors.go-part.com/xorg/"
-       "http://x.cs.pu.edu.tw/"
        "ftp://ftp.is.co.za/pub/x.org")            ; South Africa
       (cpan
        "http://www.cpan.org/"
@@ -247,20 +247,20 @@
        ;; from http://www.imagemagick.org/script/download.php
        ;; (without mirrors that are unavailable or not up to date)
        ;; mirrors keeping old versions at the top level
-       "ftp://sunsite.icm.edu.pl/packages/ImageMagick/"
+       "https://sunsite.icm.edu.pl/packages/ImageMagick/"
        ;; mirrors moving old versions to "legacy"
-       "ftp://mirror.aarnet.edu.au/pub/imagemagick/"
+       "http://mirrors-usa.go-parts.com/mirrors/ImageMagick/"
        "http://mirror.checkdomain.de/imagemagick/"
+       "http://ftp.surfnet.nl/pub/ImageMagick/"
+       "http://mirror.searchdaimon.com/ImageMagick"
+       "http://mirror.is.co.za/pub/imagemagick/"
+       "http://www.imagemagick.org/download/"
+       "ftp://mirror.aarnet.edu.au/pub/imagemagick/"
        "ftp://ftp.kddlabs.co.jp/graphics/ImageMagick/"
        "ftp://ftp.u-aizu.ac.jp/pub/graphics/image/ImageMagick/imagemagick.org/"
        "ftp://ftp.nluug.nl/pub/ImageMagick/"
-       "http://ftp.surfnet.nl/pub/ImageMagick/"
-       "http://mirror.searchdaimon.com/ImageMagick"
        "ftp://ftp.tpnet.pl/pub/graphics/ImageMagick/"
-       "http://mirror.is.co.za/pub/imagemagick/"
-       "http://mirrors-usa.go-parts.com/mirrors/ImageMagick/"
        "ftp://ftp.fifi.org/pub/ImageMagick/"
-       "http://www.imagemagick.org/download/"
        ;; one legacy location as a last resort
        "http://www.imagemagick.org/download/legacy/")
       (debian
diff --git a/guix/ftp-client.scm b/guix/ftp-client.scm
index 054a00ad7f..0b8f61c276 100644
--- a/guix/ftp-client.scm
+++ b/guix/ftp-client.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -228,7 +228,7 @@ TIMEOUT, an ETIMEDOUT error is raised."
                                 (sockaddr:scopeid sa)))
           (else #f))))
 
-(define* (ftp-list conn #:optional directory)
+(define* (ftp-list conn #:optional directory #:key timeout)
   (if directory
       (ftp-chdir conn directory))
 
@@ -236,7 +236,7 @@ TIMEOUT, an ETIMEDOUT error is raised."
          (ai   (ftp-connection-addrinfo conn))
          (s    (socket (addrinfo:fam ai) (addrinfo:socktype ai)
                        (addrinfo:protocol ai))))
-    (connect s (address-with-port (addrinfo:addr ai) port))
+    (connect* s (address-with-port (addrinfo:addr ai) port) timeout)
     (setvbuf s _IOLBF)
 
     (dynamic-wind
@@ -270,7 +270,8 @@ TIMEOUT, an ETIMEDOUT error is raised."
           (or (eqv? code 226)
               (throw 'ftp-error conn "LIST" code message)))))))
 
-(define* (ftp-retr conn file #:optional directory)
+(define* (ftp-retr conn file #:optional directory
+                   #:key timeout)
   "Retrieve FILE from DIRECTORY (or, if omitted, the current directory) from
 FTP connection CONN.  Return a binary port to that file.  The returned port
 must be closed before CONN can be used for other purposes."
@@ -291,7 +292,7 @@ must be closed before CONN can be used for other purposes."
         (or (eqv? code 226)
             (throw 'ftp-error conn "LIST" code message))))
 
-    (connect s (address-with-port (addrinfo:addr ai) port))
+    (connect* s (address-with-port (addrinfo:addr ai) port) timeout)
     (setvbuf s _IOLBF)
 
     (%ftp-command (string-append "RETR " file)
diff --git a/guix/git.scm b/guix/git.scm
index 406c817341..7a83b56216 100644
--- a/guix/git.scm
+++ b/guix/git.scm
@@ -21,7 +21,7 @@
   #:use-module (git object)
   #:use-module (guix base32)
   #:use-module (guix hash)
-  #:use-module (guix build utils)
+  #:use-module ((guix build utils) #:select (mkdir-p))
   #:use-module (guix store)
   #:use-module (guix utils)
   #:use-module (rnrs bytevectors)
@@ -55,7 +55,13 @@ make sure no empty directory is left behind."
   (with-throw-handler #t
     (lambda ()
       (mkdir-p directory)
-      (clone url directory))
+
+      ;; Note: Explicitly pass options to work around the invalid default
+      ;; value in Guile-Git: <https://bugs.gnu.org/29238>.
+      (if (module-defined? (resolve-interface '(git))
+                           'clone-init-options)
+          (clone url directory (clone-init-options))
+          (clone url directory)))
     (lambda _
       (false-if-exception (rmdir directory)))))
 
diff --git a/guix/http-client.scm b/guix/http-client.scm
index 59788c1f38..bab31875d1 100644
--- a/guix/http-client.scm
+++ b/guix/http-client.scm
@@ -302,9 +302,15 @@ Raise an '&http-get-error' condition if downloading fails."
                    (base64-encode digest 0 (bytevector-length digest)
                                   #f #f base64url-alphabet))))
 
-(define* (http-fetch/cached uri #:key (ttl (%http-cache-ttl)) text?)
+(define* (http-fetch/cached uri #:key (ttl (%http-cache-ttl)) text?
+                            (write-cache dump-port)
+                            (cache-miss (const #t)))
   "Like 'http-fetch', return an input port, but cache its contents in
-~/.cache/guix.  The cache remains valid for TTL seconds."
+~/.cache/guix.  The cache remains valid for TTL seconds.
+
+Call WRITE-CACHE with the HTTP input port and the cache output port to write
+the data to cache.  Call CACHE-MISS with URI just before fetching data from
+URI."
   (let ((file (cache-file-for-uri uri)))
     (define (update-cache cache-port)
       (define cache-time
@@ -327,11 +333,12 @@ Raise an '&http-get-error' condition if downloading fails."
                      (raise c))))
         (let ((port (http-fetch uri #:text? text?
                                 #:headers headers)))
+          (cache-miss uri)
           (mkdir-p (dirname file))
           (when cache-port
             (close-port cache-port))
           (with-atomic-file-output file
-            (cut dump-port port <>))
+            (cut write-cache port <>))
           (close-port port)
           (open-input-file file))))
 
diff --git a/guix/i18n.scm b/guix/i18n.scm
new file mode 100644
index 0000000000..f81e6b38ec
--- /dev/null
+++ b/guix/i18n.scm
@@ -0,0 +1,51 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2012, 2013, 2014, 2015, 2016, 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/>.
+
+(define-module (guix i18n)
+  #:use-module (srfi srfi-26)
+  #:export (G_
+            N_
+            P_
+            %gettext-domain
+            %package-text-domain))
+
+;;; Commentary:
+;;;
+;;; Internationalization support.
+;;;
+;;; Code:
+
+(define %gettext-domain
+  ;; Text domain for strings used in the tools.
+  "guix")
+
+(define %package-text-domain
+  ;; Text domain for package synopses and descriptions.
+  "guix-packages")
+
+(define G_ (cut gettext <> %gettext-domain))
+(define N_ (cut ngettext <> <> <> %gettext-domain))
+
+(define (P_ msgid)
+  "Return the translation of the package description or synopsis MSGID."
+  ;; Descriptions/synopses might occasionally be empty strings, even if that
+  ;; is something we try to avoid.  Since (gettext "") can return a non-empty
+  ;; string, explicitly check for that case.
+  (if (string-null? msgid)
+      msgid
+      (gettext msgid %package-text-domain)))
diff --git a/guix/import/cran.scm b/guix/import/cran.scm
index 9b08ebfb63..ec2b7e6029 100644
--- a/guix/import/cran.scm
+++ b/guix/import/cran.scm
@@ -128,30 +128,72 @@ package definition."
 (define %cran-url "http://cran.r-project.org/web/packages/")
 (define %bioconductor-url "https://bioconductor.org/packages/")
 
-;; The latest Bioconductor release is 3.5.  Bioconductor packages should be
+;; The latest Bioconductor release is 3.6.  Bioconductor packages should be
 ;; updated together.
-(define (bioconductor-mirror-url name)
-  (string-append "https://raw.githubusercontent.com/Bioconductor-mirror/"
-                 name "/release-3.5"))
+(define %bioconductor-version "3.6")
 
-(define (fetch-description repository name)
-  "Return an alist of the contents of the DESCRIPTION file for the R package
-NAME in the given REPOSITORY, or #f in case of failure.  NAME is
-case-sensitive."
-  ;; This API always returns the latest release of the module.
-  (let ((url (string-append (case repository
-                              ((cran)         (string-append %cran-url name))
-                              ((bioconductor) (bioconductor-mirror-url name)))
-                            "/DESCRIPTION")))
+(define %bioconductor-packages-list-url
+  (string-append "https://bioconductor.org/packages/"
+                 %bioconductor-version "/bioc/src/contrib/PACKAGES"))
+
+(define (bioconductor-packages-list)
+  "Return the latest version of package NAME for the current bioconductor
+release."
+  (let ((url (string->uri %bioconductor-packages-list-url)))
     (guard (c ((http-get-error? c)
                (format (current-error-port)
-                       "error: failed to retrieve package information \
-from ~s: ~a (~s)~%"
+                       "error: failed to retrieve list of packages from ~s: ~a (~s)~%"
                        (uri->string (http-get-error-uri c))
                        (http-get-error-code c)
                        (http-get-error-reason c))
                #f))
-      (description->alist (read-string (http-fetch url))))))
+      ;; Split the big list on empty lines, then turn each chunk into an
+      ;; alist of attributes.
+      (map (lambda (chunk)
+             (description->alist (string-join chunk "\n")))
+           (chunk-lines (read-lines (http-fetch/cached url)))))))
+
+(define (latest-bioconductor-package-version name)
+  "Return the version string corresponding to the latest release of the
+bioconductor package NAME, or #F if the package is unknown."
+  (and=> (find (lambda (meta)
+                 (string=? (assoc-ref meta "Package") name))
+               (bioconductor-packages-list))
+         (cut assoc-ref <> "Version")))
+
+(define (fetch-description repository name)
+  "Return an alist of the contents of the DESCRIPTION file for the R package
+NAME in the given REPOSITORY, or #f in case of failure.  NAME is
+case-sensitive."
+  (case repository
+    ((cran)
+     (let ((url (string-append %cran-url name "/DESCRIPTION")))
+       (guard (c ((http-get-error? c)
+                  (format (current-error-port)
+                          "error: failed to retrieve package information \
+from ~s: ~a (~s)~%"
+                          (uri->string (http-get-error-uri c))
+                          (http-get-error-code c)
+                          (http-get-error-reason c))
+                  #f))
+         (description->alist (read-string (http-fetch url))))))
+    ((bioconductor)
+     ;; Currently, the bioconductor project does not offer a way to access a
+     ;; package's DESCRIPTION file over HTTP, so we determine the version,
+     ;; download the source tarball, and then extract the DESCRIPTION file.
+     (let* ((version (latest-bioconductor-package-version name))
+            (url     (car (bioconductor-uri name version)))
+            (tarball (with-store store (download-to-store store url))))
+       (call-with-temporary-directory
+        (lambda (dir)
+          (parameterize ((current-error-port (%make-void-port "rw+"))
+                         (current-output-port (%make-void-port "rw+")))
+            (and (zero? (system* "tar" "--wildcards" "-x"
+                                 "--strip-components=1"
+                                 "-C" dir
+                                 "-f" tarball "*/DESCRIPTION"))
+                 (description->alist (with-input-from-file
+                                         (string-append dir "/DESCRIPTION") read-string))))))))))
 
 (define (listify meta field)
   "Look up FIELD in the alist META.  If FIELD contains a comma-separated
@@ -419,16 +461,15 @@ dependencies."
   (define upstream-name
     (package->upstream-name package))
 
-  (define meta
-    (fetch-description 'bioconductor upstream-name))
+  (define version
+    (latest-bioconductor-package-version upstream-name))
 
-  (and meta
-       (let ((version (assoc-ref meta "Version")))
-         ;; Bioconductor does not provide signatures.
-         (upstream-source
-          (package (package-name package))
-          (version version)
-          (urls (list (bioconductor-uri upstream-name version)))))))
+  (and version
+       ;; Bioconductor does not provide signatures.
+       (upstream-source
+        (package (package-name package))
+        (version version)
+        (urls (bioconductor-uri upstream-name version)))))
 
 (define (cran-package? package)
   "Return true if PACKAGE is an R package from CRAN."
diff --git a/guix/import/utils.scm b/guix/import/utils.scm
index 1e2f0c809d..d4cef6b503 100644
--- a/guix/import/utils.scm
+++ b/guix/import/utils.scm
@@ -34,6 +34,8 @@
   #:use-module (guix download)
   #:use-module (gnu packages)
   #:use-module (ice-9 match)
+  #:use-module (ice-9 rdelim)
+  #:use-module (ice-9 receive)
   #:use-module (ice-9 regex)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-11)
@@ -56,7 +58,10 @@
             snake-case
             beautify-description
 
-            alist->package))
+            alist->package
+
+            read-lines
+            chunk-lines))
 
 (define (factorize-uri uri version)
   "Factorize URI, a package tarball URI as a string, such that any occurrences
@@ -329,3 +334,24 @@ the expected fields of an <origin> object."
        (or (module-ref (resolve-interface '(guix licenses) #:prefix 'license:)
                        (spdx-string->license l))
            (license:fsdg-compatible l))))))
+
+(define* (read-lines #:optional (port (current-input-port)))
+  "Read lines from PORT and return them as a list."
+  (let loop ((line (read-line port))
+             (lines '()))
+    (if (eof-object? line)
+        (reverse lines)
+        (loop (read-line port)
+              (cons line lines)))))
+
+(define* (chunk-lines lines #:optional (pred string-null?))
+  "Return a list of chunks, each of which is a list of lines.  The chunks are
+separated by PRED."
+  (let loop ((rest lines)
+             (parts '()))
+    (receive (before after)
+        (break pred rest)
+      (let ((res (cons before parts)))
+        (if (null? after)
+            (reverse res)
+            (loop (cdr after) res))))))
diff --git a/guix/licenses.scm b/guix/licenses.scm
index 6de611da2b..b07d80076e 100644
--- a/guix/licenses.scm
+++ b/guix/licenses.scm
@@ -42,7 +42,7 @@
             cc-by2.0 cc-by3.0 cc-by4.0
             cc-by-sa2.0 cc-by-sa3.0 cc-by-sa4.0
             cc-sampling-plus-1.0
-            cddl1.0
+            cddl1.0 cddl1.1
             cecill cecill-b cecill-c
             artistic2.0 clarified-artistic
             copyleft-next
@@ -217,6 +217,14 @@ at URI, which may be a file:// URI pointing the package's tree."
            "http://directory.fsf.org/wiki/License:CDDLv1.0"
            "https://www.gnu.org/licenses/license-list#CDDL"))
 
+;; CDDL1.1 is the same as 1.0, except that "Sun Microsystems, Inc" becomes "Oracle",
+;; "LOST PROFITS" becoms "LOSS OF GOODWILL" and a section is added between 6.2
+;; and 6.3.
+(define cddl1.1
+  (license "CDDL 1.1"
+           "https://oss.oracle.com/licenses/CDDL+GPL-1.1"
+           "https://www.gnu.org/licenses/license-list#CDDL"))
+
 (define cecill                                    ;copyleft
   (license "CeCILL"
            "http://www.cecill.info/licences/Licence_CeCILL_V2.1-en.html"
diff --git a/guix/records.scm b/guix/records.scm
index 7de5fccef6..1f00e16603 100644
--- a/guix/records.scm
+++ b/guix/records.scm
@@ -26,7 +26,8 @@
   #:export (define-record-type*
             alist->record
             object->fields
-            recutils->alist))
+            recutils->alist
+            match-record))
 
 ;;; Commentary:
 ;;;
@@ -375,4 +376,19 @@ pairs.  Stop upon an empty line (after consuming it) or EOF."
               (else
                (error "unmatched line" line))))))))
 
+(define-syntax match-record
+  (syntax-rules ()
+    "Bind each FIELD of a RECORD of the given TYPE to it's FIELD name.
+The current implementation does not support thunked and delayed fields."
+    ((_ record type (field fields ...) body ...)
+     (if (eq? (struct-vtable record) type)
+         ;; TODO compute indices and report wrong-field-name errors at
+         ;;      expansion time
+         ;; TODO support thunked and delayed fields
+         (let ((field ((record-accessor type 'field) record)))
+           (match-record record type (fields ...) body ...))
+         (throw 'wrong-type-arg record)))
+    ((_ record type () body ...)
+     (begin body ...))))
+
 ;;; records.scm ends here
diff --git a/guix/scripts/refresh.scm b/guix/scripts/refresh.scm
index 852b44b38d..a8fe993e33 100644
--- a/guix/scripts/refresh.scm
+++ b/guix/scripts/refresh.scm
@@ -273,7 +273,8 @@ the latest known version of ~a (~a)~%")
 
 (define (all-packages)
   "Return the list of all the distro's packages."
-  (fold-packages cons '()))
+  (fold-packages cons '()
+                 #:select? (const #t)))           ;include hidden packages
 
 (define (list-dependents packages)
   "List all the things that would need to be rebuilt if PACKAGES are changed."
diff --git a/guix/ui.scm b/guix/ui.scm
index 3c8734a7d5..0fc5ab63ad 100644
--- a/guix/ui.scm
+++ b/guix/ui.scm
@@ -26,6 +26,7 @@
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
 (define-module (guix ui)
+  #:use-module (guix i18n)
   #:use-module (guix gexp)
   #:use-module (guix utils)
   #:use-module (guix store)
@@ -55,10 +56,8 @@
   #:use-module (texinfo)
   #:use-module (texinfo plain-text)
   #:use-module (texinfo string-utils)
-  #:export (G_
-            N_
-            P_
-            report-error
+  #:re-export (G_ N_ P_)                          ;backward compatibility
+  #:export (report-error
             leave
             make-user-module
             load*
@@ -111,26 +110,6 @@
 ;;;
 ;;; Code:
 
-(define %gettext-domain
-  ;; Text domain for strings used in the tools.
-  "guix")
-
-(define %package-text-domain
-  ;; Text domain for package synopses and descriptions.
-  "guix-packages")
-
-(define G_ (cut gettext <> %gettext-domain))
-(define N_ (cut ngettext <> <> <> %gettext-domain))
-
-(define (P_ msgid)
-  "Return the translation of the package description or synopsis MSGID."
-  ;; Descriptions/synopses might occasionally be empty strings, even if that
-  ;; is something we try to avoid.  Since (gettext "") can return a non-empty
-  ;; string, explicitly check for that case.
-  (if (string-null? msgid)
-      msgid
-      (gettext msgid %package-text-domain)))
-
 (define-syntax-rule (define-diagnostic name prefix)
   "Create a diagnostic macro (i.e., NAME), which will prepend PREFIX to all
 messages."
@@ -170,6 +149,18 @@ messages."
     (report-error args ...)
     (exit 1)))
 
+(define (print-unbound-variable-error port key args default-printer)
+  ;; Print unbound variable errors more nicely, and in the right language.
+  (match args
+    ((proc message (variable) _ ...)
+     ;; We can always omit PROC because when it's useful (i.e., different from
+     ;; "module-lookup"), it gets displayed before.
+     (format port (G_ "~a: unbound variable") variable))
+    (_
+     (default-printer))))
+
+(set-exception-printer! 'unbound-variable print-unbound-variable-error)
+
 (define (make-user-module modules)
   "Return a new user module with the additional MODULES loaded."
   ;; Module in which the machine description file is loaded.
@@ -250,6 +241,45 @@ messages."
              (else
               #t))))))
 
+(define (known-variable-definition variable)
+  "Search among the currently loaded modules one that defines a variable named
+VARIABLE and return it, or #f if none was found."
+  (define (module<? m1 m2)
+    (match (module-name m2)
+      (('gnu _ ...) #t)
+      (('guix _ ...)
+       (match (module-name m1)
+         (('gnu _ ...) #f)
+         (_ #t)))
+      (_ #f)))
+
+  (let loop ((modules (list (resolve-module '() #f #f #:ensure #f)))
+             (suggestions '()))
+    (match modules
+      (()
+       ;; Pick the "best" suggestion.
+       (match (sort suggestions module<?)
+         (() #f)
+         ((first _ ...) first)))
+      ((head tail ...)
+       (let ((next (append tail
+                           (hash-map->list (lambda (name module)
+                                             module)
+                                           (module-submodules head)))))
+         (match (module-local-variable head variable)
+           (#f (loop next suggestions))
+           (_
+            (match (module-name head)
+              (('gnu _ ...) head)                 ;must be that one
+              (_ (loop next (cons head suggestions)))))))))))
+
+(define* (display-hint message #:optional (port (current-error-port)))
+  "Display MESSAGE, a l10n message possibly containing Texinfo markup, to
+PORT."
+  (format port (G_ "hint: ~a~%")
+          (fill-paragraph (texi->plain-text message)
+                          (terminal-columns) 8)))
+
 (define* (report-load-error file args #:optional frame)
   "Report the failure to load FILE, a user-provided Scheme file.
 ARGS is the list of arguments received by the 'throw' handler."
@@ -270,12 +300,30 @@ ARGS is the list of arguments received by the 'throw' handler."
      (let ((loc (source-properties->location properties)))
        (format (current-error-port) (G_ "~a: error: ~a~%")
                (location->string loc) message)))
+    (('unbound-variable proc message (variable) _ ...)
+     (match args
+       ((key . args)
+        (print-exception (current-error-port) frame key args)))
+     (match (known-variable-definition variable)
+       (#f
+        (display-hint (G_ "Did you forget a @code{use-modules} form?")))
+       (module
+        (display-hint (format #f (G_ "Try adding @code{(use-modules ~a)}.")
+                              (module-name module))))))
     (('srfi-34 obj)
      (if (message-condition? obj)
-         (report-error (G_ "~a~%")
-                       (gettext (condition-message obj)
-                                %gettext-domain))
-         (report-error (G_ "exception thrown: ~s~%") obj)))
+         (if (error-location? obj)
+             (format (current-error-port)
+                     (G_ "~a: error: ~a~%")
+                     (location->string (error-location obj))
+                     (gettext (condition-message obj)
+                              %gettext-domain))
+             (report-error (G_ "~a~%")
+                           (gettext (condition-message obj)
+                                    %gettext-domain)))
+         (report-error (G_ "exception thrown: ~s~%") obj))
+     (when (fix-hint? obj)
+       (display-hint (condition-fix-hint obj))))
     ((error args ...)
      (report-error (G_ "failed to load '~a':~%") file)
      (apply display-error frame (current-error-port) args))))
@@ -538,6 +586,11 @@ interpreted."
 directories:~{ ~a~}~%")
                     (file-search-error-file-name c)
                     (file-search-error-search-path c)))
+            ((and (error-location? c) (message-condition? c))
+             (format (current-error-port)
+                     (G_ "~a: error: ~a~%")
+                     (location->string (error-location c))
+                     (gettext (condition-message c) %gettext-domain)))
             ((message-condition? c)
              ;; Normally '&message' error conditions have an i18n'd message.
              (leave (G_ "~a~%")
@@ -1068,9 +1121,14 @@ score, the more relevant OBJ is to REGEXPS."
 (define %package-metrics
   ;; Metrics used to compute the "relevance score" of a package against a set
   ;; of regexps.
-  `((,package-name . 3)
-    (,package-synopsis-string . 2)
-    (,package-description-string . 1)))
+  `((,package-name . 4)
+    (,package-synopsis-string . 3)
+    (,package-description-string . 2)
+    (,(lambda (type)
+        (match (and=> (package-location type) location-file)
+          ((? string? file) (basename file ".scm"))
+          (#f "")))
+     . 1)))
 
 (define (package-relevance package regexps)
   "Return a score denoting the relevance of PACKAGE for REGEXPS.  A score of
diff --git a/guix/utils.scm b/guix/utils.scm
index eb1ec29b32..c0ffed172a 100644
--- a/guix/utils.scm
+++ b/guix/utils.scm
@@ -28,6 +28,7 @@
   #:use-module (srfi srfi-9)
   #:use-module (srfi srfi-11)
   #:use-module (srfi srfi-26)
+  #:use-module (srfi srfi-35)
   #:use-module (srfi srfi-39)
   #:use-module (ice-9 binary-ports)
   #:autoload   (rnrs io ports) (make-custom-binary-input-port)
@@ -60,6 +61,14 @@
             source-properties->location
             location->source-properties
 
+            &error-location
+            error-location?
+            error-location
+
+            &fix-hint
+            fix-hint?
+            condition-fix-hint
+
             nix-system->gnu-triplet
             gnu-triplet->nix-system
             %current-system
@@ -750,6 +759,14 @@ a location object."
     (column   . ,(location-column loc))
     (filename . ,(location-file loc))))
 
+(define-condition-type &error-location &error
+  error-location?
+  (location  error-location))                     ;<location>
+
+(define-condition-type &fix-hint &condition
+  fix-hint?
+  (hint condition-fix-hint))                      ;string
+
 ;;; Local Variables:
 ;;; eval: (put 'call-with-progress-reporter 'scheme-indent-function 1)
 ;;; End:
diff --git a/guix/workers.scm b/guix/workers.scm
index 846f5e50a9..3cd683c96d 100644
--- a/guix/workers.scm
+++ b/guix/workers.scm
@@ -45,12 +45,13 @@
 ;;; Code:
 
 (define-record-type <pool>
-  (%make-pool queue mutex condvar workers)
+  (%make-pool queue mutex condvar workers busy)
   pool?
   (queue    pool-queue)
   (mutex    pool-mutex)
   (condvar  pool-condition-variable)
-  (workers  pool-workers))
+  (workers  pool-workers)
+  (busy     pool-busy))
 
 (define-syntax-rule (without-mutex mutex exp ...)
   (dynamic-wind
@@ -62,22 +63,26 @@
       (lock-mutex mutex))))
 
 (define* (worker-thunk mutex condvar pop-queue
-                       #:key (thread-name "guix worker"))
+                       #:key idle busy (thread-name "guix worker"))
   "Return the thunk executed by worker threads."
   (define (loop)
     (match (pop-queue)
       (#f                                         ;empty queue
-       (wait-condition-variable condvar mutex))
+       (idle)
+       (wait-condition-variable condvar mutex)
+       (busy))
       ((? procedure? proc)
        ;; Release MUTEX while executing PROC.
        (without-mutex mutex
          (catch #t proc
+           (const #f)
            (lambda (key . args)
              ;; XXX: In Guile 2.0 ports are not thread-safe, so this could
              ;; crash (Guile 2.2 is fine).
              (display-backtrace (make-stack #t) (current-error-port))
              (print-exception (current-error-port)
-                              (stack-ref (make-stack #t) 0)
+                              (and=> (make-stack #t)
+                                     (cut stack-ref <> 0))
                               key args))))))
     (loop))
 
@@ -97,19 +102,24 @@ threads as reported by the operating system."
   (let* ((mutex   (make-mutex))
          (condvar (make-condition-variable))
          (queue   (make-q))
+         (busy    count)
          (procs   (unfold (cut >= <> count)
                           (lambda (n)
                             (worker-thunk mutex condvar
                                           (lambda ()
                                             (and (not (q-empty? queue))
                                                  (q-pop! queue)))
+                                          #:busy (lambda ()
+                                                   (set! busy (+ 1 busy)))
+                                          #:idle (lambda ()
+                                                   (set! busy (- busy 1)))
                                           #:thread-name thread-name))
                           1+
                           0))
          (threads (map (lambda (proc)
                          (call-with-new-thread proc))
                        procs)))
-    (%make-pool queue mutex condvar threads)))
+    (%make-pool queue mutex condvar threads (lambda () busy))))
 
 (define (pool-enqueue! pool thunk)
   "Enqueue THUNK for future execution by POOL."
@@ -118,9 +128,11 @@ threads as reported by the operating system."
     (signal-condition-variable (pool-condition-variable pool))))
 
 (define (pool-idle? pool)
-  "Return true if POOL doesn't have any task in its queue."
+  "Return true if POOL doesn't have any task in its queue and all the workers
+are currently idle (i.e., waiting for a task)."
   (with-mutex (pool-mutex pool)
-    (q-empty? (pool-queue pool))))
+    (and (q-empty? (pool-queue pool))
+         (zero? ((pool-busy pool))))))
 
 (define-syntax-rule (eventually pool exp ...)
   "Run EXP eventually on one of the workers of POOL."