* guix/graph.scm (%graph-backends): New variable.
* guix/scripts/graph.scm (lookup-backend, list-backends): New
procedures.
(%options): Add options for "backend" and "list-backends".
(show-help): Add help texts for "backend" and "list-backend" options.
(%default-options): Add "backend" default.
(guix-graph): Pass backend argument to "export-graph".
* doc/guix.texi (Invoking guix graph): Document the new options.
* guix/scripts/graph.scm (ensure-store-items): New procedure.
(%reference-node-type)[convert]: Use it.
(non-derivation-referrers): New procedure.
(%referrer-node-type): New variable.
(%node-types): Add it.
* tests/graph.scm ("referrer DAG"): New test.
* doc/guix.texi (Invoking guix graph): Document it.
Previously 'GUIX_BUILD_OPTIONS' would be honored, but 'guix graph' does
not support the common build options.
* guix/scripts/graph.scm (guix-graph): Use 'args-fold*' instead of
'parse-command-line'.
Fixes <http://bugs.gnu.org/22139>.
* guix/grafts.scm (graft-derivation): Rename to...
(graft-derivation/shallow): ... this.
(graft-origin-file-name, item->deriver, non-self-references)
(cumulative-grafts, graft-derivation): New procedures
* tests/grafts.scm ("graft-derivation, grafted item is a direct
dependency"): Clarify title. Use 'grafted' instead of 'graft' to refer
to the grafted derivation.
("graft-derivation, grafted item is an indirect dependency")
("graft-derivation, no dependencies on grafted output"): New tests.
* guix/packages.scm (input-graft): Change to take a package instead of
an input.
(input-cross-graft): Likewise.
(fold-bag-dependencies): New procedure.
(bag-grafts): Rewrite in terms of 'fold-bag-dependencies'.
* tests/packages.scm ("package-derivation, indirect grafts"): Comment out.
* doc/guix.texi (Security Updates): Mention run-time dependencies and
recursive grafting.
Before that it would include #f for most origins since that the default
value of 'origin-patch-guile'.
* guix/scripts/graph.scm (bag-node-edges): When 'origin-patch-guile'
returns #f, use (default-guile).
* tests/graph.scm ("bag DAG, including origins"): Check for an edge from
O to (default-guile).
Fixes <http://bugs.gnu.org/22280>.
Reported by Leo Famulari <leo@famulari.name>.
* guix/scripts/graph.scm (%bag-emerged-node-type)[edges]: Mimic
%BAG-NODE-TYPE. This is a followup to 38b92da.
