[bug#41164] [PATCH 0/3] Add 'guix graph --path'

[Ludovic Courtès]

Hello!

The attached patches add ‘guix graph --path’, a command to display
the shortest path between two nodes:

--8<---------------cut here---------------start------------->8---
$ ./pre-inst-env guix graph --path emacs libffi
emacs@26.3
gnutls@3.6.9
guile@2.2.6
libffi@3.2.1
$ ./pre-inst-env guix graph --path -t derivation emacs libffi
/gnu/store/aswcmllr300bbsiv1i63idpivzkzq2f2-emacs-26.3.drv
/gnu/store/dfcgalgx2fnc7alsi0qdjfzghn517ha3-libffi-3.2.1.drv
$ ./pre-inst-env guix graph --path -t references libreoffice llvm@9
/gnu/store/1rbww1g8q5sc9x3v318wp6xn62832n5m-libreoffice-6.4.2.2
/gnu/store/ir05kr2z31xgaih9k5z4xah7k3gqs0sk-libepoxy-1.5.4
/gnu/store/2mf0clz9w64diy0kz11qcs4q5wg9hc6z-mesa-19.3.4
/gnu/store/vsd496n5arjjlriqw914syirhyscq8q1-llvm-9.0.1
--8<---------------cut here---------------end--------------->8---

It was long overdue, and it’s rather cool.

There’s a bikeshedding opportunity in the last patch: should it go
in ‘guix graph’ or elsewhere?  I think ‘guix graph’ is a good home
for that, and could eventually include more graph queries.  For
instance, ‘guix refresh -l’ could very well live in ‘guix graph’.

Feedback welcome!

Ludo’.

Ludovic Courtès (3):
  graph: reference/referrer node types work with graph traversal.
  graph: Add 'shortest-path'.
  guix graph: Add '--path'.

 doc/guix.texi          | 48 ++++++++++++++++++++++-
 guix/graph.scm         | 69 ++++++++++++++++++++++++++++++++-
 guix/scripts/graph.scm | 69 +++++++++++++++++++++++++++------
 tests/graph.scm        | 88 ++++++++++++++++++++++++++++++++++++++++++
 tests/guix-graph.sh    | 16 +++++++-
 5 files changed, 274 insertions(+), 16 deletions(-)

-- 
2.26.2