graph: Add synthetic test.

* tests/graph.scm ("node-transitive-edges, no duplicates"): New test.

import: cran: Parse DESCRIPTION instead of HTML.

* guix/import/cran.scm (description->alist, listify,
  beautify-description, description->package): New procedures.
(table-datum, downloads->url, nodes->text, cran-sxml->sexp): Remove
proceduces.
(latest-release): Use parsed DESCRIPTION instead of SXML.
* tests/cran.scm: Rewrite to match importer.

derivations: Determine what's built in 'check' mode.

* guix/derivations.scm (substitution-oracle): Add #:mode parameter and
honor it.
(derivation-prerequisites-to-build): Likewise.
[derivation-built?]: Take it into account.
* guix/ui.scm (show-what-to-build): Add #:mode parameter.  Pass it to
'substitute-oracle' and 'derivations-prerequisites-to-build'.
* tests/derivations.scm ("derivation-prerequisites-to-build in 'check'
mode"): New test.

store: Allow clients to request multiple builds.

* guix/store.scm (set-build-options): Add #:rounds parameter and honor it.
* tests/store.scm ("build multiple times"): New test.

gnu-maintenance: Add tests for 'release-file?'.

* tests/gnu-maintenance.scm: New file.
* Makefile.am (SCM_TESTS): Add it.
* guix/gnu-maintenance.scm (release-file?): Export.

store: Add mode parameter to 'build-paths'.

* guix/store.scm (%protocol-version): Set minor to 15.
(build-mode): New enumerate type.
(build-things): Add 'mode' parameter; pass it to the RPC.
* tests/store.scm ("build-things, check mode"): New check.

lint: Do not report already-patched vulnerabilities.

* guix/scripts/lint.scm (patch-file-name): New procedure.
(check-vulnerabilities): Use it to filter out patched vulnerabilities.
* tests/lint.scm ("cve: one patched vulnerability"): New test.

lint: Add "cve" checker.

Fixes <http://bugs.gnu.org/21289>.

* guix/scripts/lint.scm (package-name->cpe-name, package-vulnerabilities)
(check-vulnerabilities): New procedures.
* guix/scripts/lint.scm (%checkers): Add "cve" checker.
* tests/lint.scm ("cve", "cve: one vulnerability"): New tests.
* doc/guix.texi (Invoking guix lint): Mention it.

Add (guix cve).

* guix/cve.scm, tests/cve-sample.xml, tests/cve.scm: New files.
* Makefile.am (MODULES): Add guix/cve.scm.
(SCM_TESTS): Add tests/cve.scm.
(EXTRA_DIST): Add tests/cve-sample.scm.

import: hackage: Add new tests.

* tests/hackage.scm (eval-test-with-cabal): Add optional argument.
  (test-cabal-3): New variable and test.
  (test-read-cabal-1): Exercise more parsing variants.

utils: Add 'canonical-newline-port'.

* guix/utils.scm (canonical-newline-port): New procedure.
* tests/utils.scm ("canonical-newline-port"): New test.

services: dmd: Error out upon unmet dmd requirements.

* gnu/services/dmd.scm (assert-no-duplicates): Rename to...
(assert-valid-graph): ... this.
[provisions]: New variable.
[assert-satisfied-requirements]: New procedure.
Use it.
* tests/guix-system.sh: Add test with unmet dmd requirements.

graph: Add '%bag-with-origins-node-type'.

* guix/scripts/graph.scm (bag-node-edges): Remove 'filter' call.  Add
case for 'origin'.
(%bag-node-type)[edges]: Add filtering here.
(%bag-with-origins-node-type): New variable.
(%node-types): Add it.
* tests/graph.scm ("bag DAG, including origins"): New test.
* tests/guix-graph.sh: Add 'bag-with-origins'.
* doc/guix.texi (Invoking guix graph): Document it.

guix download: Fail when more than one URL is passed.

* guix/scripts/download.scm (guix-download)[parse-option]: Call 'leave'
when passed an extra argument.
* tests/guix-download.sh: Add test.

environment: Correctly handle abnormal exits.

Fixes <http://bugs.gnu.org/21958>.

* guix/scripts/environment.scm (status->exit-code): New procedure.
(exit/status, primitive-exit/status): Use it.
* tests/guix-environment-container.sh: Add test.

tests: Skip 'guix-container-environment.sh' when support is missing.

Fixes <http://bugs.gnu.org/21410>.
Reported by Alex Vong <alexvong1995@gmail.com>.

* tests/guix-environment-container.sh: Exit with 77 when
'((@@ (guix scripts environment) assert-container-features))' fails.

graph: Add procedures to query a node's edges.

* guix/graph.scm (%node-edges, node-edges, node-back-edges)
(node-transitive-edges): New procedures.
* tests/graph.scm ("node-edges")
("node-transitive-edges + node-back-edges"): New tests.

Add (guix graph).

* guix/scripts/graph.scm (<node-type>, <graph-backend>, emit-prologue)
(emit-epilogue, emit-node, emit-edge, %graphviz-backend, export-graph):
Move to...
* guix/graph.scm: ... here.  New file.
* guix/scripts/system.scm, tests/graph.scm: Use it.
* Makefile.am (MODULES): Add it.

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.

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.