Merge branch 'master' into core-updates

guix system: init: Overwrite the items in the target store.

Fixes <http://bugs.gnu.org/20722>.
Reported by Eric Bavier <ericbavier@openmailbox.org>.

* guix/scripts/system.scm (copy-item): Check whether DEST exists and remove it
  if it does.

import: hackage: Refactor parsing code and add new options.

* guix/import/cabal.scm: New file.
* guix/import/hackage.scm: Update to use the new Cabal parsing module.
* tests/hackage.scm: Update tests.
* guix/scripts/import/hackage.scm: Add new '--cabal-environment' and '--stdin'
  options.
* doc/guix.texi: ... and document them.
* Makefile.am (MODULES): Add 'guix/import/cabal.scm',
  'guix/import/hackage.scm' and 'guix/scripts/import/hackage.scm'.
  (SCM_TESTS): Add 'tests/hackage.scm'.

guix: Clean up --help messages.

* guix/scripts/import.scm (show-help): Add newline before a list of
  importers.
* guix/scripts/lint.scm (show-help): Split a long description line.
* guix/scripts/package.scm (show-help): Improve docstrings for --install
  and --remove options.
* guix/scripts/system.scm (show-help): Format actions the same way as
  guix commands and importers are formatted.

guix gc: Add '--verify'.

* guix/scripts/gc.scm (show-help, %options): Add --verify.
  (guix-gc): Handle it.
* doc/guix.texi (Invoking guix gc): Document --verify, and move --optimize
  description right below it.

guix package: Fix typo in --help message.

* guix/scripts/package.scm (show-help): Align '--show' option properly.

lint: source: Warn only when all the URIs are unreachable.

* guix/scripts/lint.scm (call-with-accumulated-warnings): New procedure.
  (with-accumulated-warnings): New macro.
  (check-source): Add 'try-uris' and use it.  Emit warnings only upon
  failure.

lint: 'validate-uri' really returns #f on failure.

* guix/scripts/lint.scm (validate-uri): Always return #f on failure.

emacs: Report about "search paths" after operation.

* guix/scripts/package.scm: Export 'display-search-paths'.
* emacs/guix-main.scm (process-package-actions): Use it.

guix environment: Add --ad-hoc option.

* guix/scripts/environment.scm (%options): Add "ad-hoc" option.
  (show-help): Display help for "--ad-hoc".
  (packages+propagated-inputs): New procedure.
  (guix-environment): Create ad hoc environment when asked.
* doc/guix.texi ("invoking guix environment"): Document it.

gc: ignore trailing slash or subdirectories for `guix gc -d'

Fixes <http://bugs.gnu.org/19757>.

* guix/scripts/gc.scm (guix-gc): Convert paths to direct store paths.
* guix/store.scm (direct-store-path): Get rid of subdirectories in store path.
* tests/guix-gc.sh: New tests.

Co-authored-by: Ludovic Courtès <ludo@gnu.org>

guix system: Add '--on-error'.

* guix/ui.scm (load*): Add #:on-error parameter.
  [tag, error-string]: New variables.
  Wrap 'load' call in 'call-with-prompt'.  Pass TAG to 'make-stack'.  Honor
  ON-ERROR after 'report-load-error' call.
  (report-load-error): Change to not exit on error.  Make private.
* guix/scripts/system.scm (show-help, %options): Add --on-error.
  (guix-system): Use 'load*' and pass it #:on-error.

guix package: --manifest DTRT when combined with --dry-run.

* guix/scripts/package.scm (guix-package)[process-actions]: Process 'manifest
  action regardless of whether 'dry-run? is set.  Adjust the message
  accordingly.
* tests/guix-package.sh: Add error-reporting test.

guix system: init: Copy the closure of 'grub.cfg', not that of the system.

Fixes <http://bugs.gnu.org/20591>.
Reported by Daniel Pimentel <d4n1@openmailbox.org>.

* guix/scripts/system.scm (install): Copy the closure of GRUB.CFG rather than
  that of OS-DIR.

guix system: Always add zero previous entries in grub.cfg for 'init'.

* guix/scripts/system.scm (grub.cfg): Remove.
  (perform-action): Call 'operating-system-grub.cfg' with the empty list as
  the 2nd argument when ACTION is 'init.

Merge branch 'master' into gtk-rebuild

guix system: init: Make sure the target is root-owned.

Suggested by Mark H Weaver <mhw@netris.org>.

* guix/scripts/system.scm (install): Add 'chown' and 'chmod' calls for TARGET
  when running as root, and warn otherwise.

Merge branch 'master' into gtk-rebuild

Conflicts:
	gnu/packages/gtk.scm

guix package: Adjust --help message.

* guix/scripts/package.scm (show-help): Add KIND parameter for
  --search-paths as a followup to dbc31ab.

scripts: Move 'set-build-options-from-command-line*' to (guix scripts build) module.

* guix/scripts/build.scm (set-build-options-from-command-line*): New
  procedure.
* guix/scripts/environment.scm (set-build-options-from-command-line*): Delete.