graft: Graft files in parallel.

* guix/build/graft.scm (rewrite-directory): Use 'n-par-for-each' instead
  of 'for-each'.

graft: Graft files in a deterministic order.

* guix/build/graft.scm (rewrite-directory)[rewrite-leaf]: Change to take
  a single parameter.  Add call to 'lstat'.  Factorize result of
  'destination'.
  Use 'find-files' instead of 'file-system-fold'.

lint: Have connections time out after 3 seconds.

* guix/scripts/lint.scm (probe-uri): Add #:timeout parameter.  Pass it
  to 'open-connection-for-uri' and 'ftp-open'.
  (validate-uri): Pass #:timeout 3 to 'probe-uri'.

download: Always use AI_ADDRCONFIG when resolving host names.

* guix/build/download.scm (open-socket-for-uri): Always pass
  AI_ADDRCONFIG to 'getaddrinfo' as recommended in the fine Guile
  manual.
* guix/ftp-client.scm (ftp-open): Ditto.

download: Add timeout parameter for connections.

* guix/build/download.scm (ensure-uri): New procedure.
(current-http-proxy): New variable.
(open-socket-for-uri): Copy from Guile commit aaea5b2, but add #:timeout
parameter and use 'connect*' instead of 'connect'.
(open-connection-for-uri): Add #:timeout parameter and pass it to
'open-socket-for-uri'.

ftp-client: Add timeout parameter to 'ftp-open'.

* guix/ftp-client.scm (catch-EINPROGRESS): New macro.
(connect*): New procedure.
(ftp-open): Add #:timeout parameter.  Use 'connect*' instead of
'connect' and pass it TIMEOUT.

ftp-client: Restrict to TCP connections.

* guix/ftp-client.scm (ftp-open): Force SOCK_STREAM as the socket type
  to avoid calling 'connect' on a datagram socket.

guix gc: Error out when extra arguments are passed.

Fixes <http://bugs.gnu.org/21817>.
Reported by Petter Berntsen <petter@mykolab.ch>.

* guix/scripts/gc.scm (guix-gc)[assert-no-extra-arguments]: New
  procedure.
  Use it for actions 'collect-garbage', 'optimize', and 'verify'.
* tests/guix-gc.sh: Add tests.

edit: Honor $VISUAL.

Suggested by Andreas Enge <andreas@enge.fr>.

* guix/scripts/edit.scm (%editor): Honor 'VISUAL' before 'EDITOR'.
  (show-help): Adjust accordingly.
* doc/guix.texi (Invoking guix edit): Likewise.

refresh: Avoid non-literal format string.

Reported by Mathieu Lirzin <mthl@gnu.org>.

* guix/scripts/refresh.scm (guix-refresh): Rewrite 'list-dependent?'
  report to avoid nested 'N_' calls.

ui: 'guix help COMMAND' is like 'guix COMMAND --help'.

* guix/ui.scm (run-guix): Add ("help" COMMAND) case.

guix package: '--search-paths' can report combined search paths.

Partly fixes <http://bugs.gnu.org/20255>.

* guix/scripts/package.scm (search-path-environment-variables): Change
  'profile' to 'profiles'; expect it to be a list.
  (display-search-paths): Likewise.
  (%default-options): Remove 'profile' entry.
  (%options) <--profile>: Keep previous values associated with 'profile'
  in RESULT.
  (guix-package)[process-actions, process-query]: Handle the possible
  lack of 'profile' pair in OPTS.

refresh: Discard PyPI updater when Guile-JSON is missing.

Reported by Sleep_Walker and Mathieu Lirzin <mthl@gnu.org>.

* guix/scripts/refresh.scm (maybe-updater, list-updaters): New macros.
  (%updaters): Use 'list-updaters' instead of 'list'.  Make
  %PYPI-UPDATER conditional.

edit: Improve error reporting when $EDITOR is not found.

Reported by Benno Evers <benno@bmevers.de>
at <https://lists.gnu.org/archive/html/guix-devel/2015-11/msg00125.html>.

* guix/scripts/edit.scm (guix-edit): Wrap 'execl' call in 'catch'.
  Provide more meaningful error message.

edit: Lift helper procedure.

* guix/scripts/edit.scm (package->location-specification): New
  procedure, with code formerly...
  (guix-edit): ... here.  Use it.

import: hackage: Fix invalid use of 'leave'.

Reported by Paul van der Walt <paul@denknerd.org>
in <http://bugs.gnu.org/21829>.

* guix/scripts/import/hackage.scm (guix-import-hackage): Add missing
  argument in call to 'leave'.

build-system/python: 'package-with-python2' preserves source location.

* guix/build-system/python.scm (package-with-explicit-python): Add
  'location' field.

import: pypi: Make downloads silent.

* guix/import/pypi.scm (pypi-fetch): Wrap body in
  'call-with-output-file' and 'with-error-to-port'.

import: pypi: Add missing copyright line.

* guix/import/pypi.scm: Add missing copyright line for bab020d.

scripts: container: Fix 'exec' command line parsing.

* guix/scripts/container/exec.scm (partition-args): Reimplement such
  that all args up to and including the PID are returned as the first of
  the two values.