bug#56398: (guix git) fails to check out repos with nested submodules

[Ludovic Courtès]

Hello,

It seems that ‘update-cached-checkout’ fails to handle nested Git
submodules, when a submodule itself has submodules:

--8<---------------cut here---------------start------------->8---
$ ./pre-inst-env guix refresh python-pytorch
gnu/packages/machine-learning.scm:2872:13: python-pytorch would be upgraded 
from 1.11.0 to 1.12.0
$ ./pre-inst-env  guix refresh -u python-pytorch
Backtrace:
In ice-9/eval.scm:
    619:8 19 (_ #(#(#<directory (guile-user) 7f5a34cc2c80>)))
In guix/ui.scm:
   2238:7 18 (run-guix . _)
  2201:10 17 (run-guix-command _ . _)
In ice-9/boot-9.scm:
  1752:10 16 (with-exception-handler _ _ #:unwind? _ # _)
  1752:10 15 (with-exception-handler _ _ #:unwind? _ # _)
In guix/store.scm:
   659:37 14 (thunk)
  2168:25 13 (run-with-store #<store-connection 256.99 7f5a212475f0> …)
In guix/scripts/refresh.scm:
   560:16 12 (_ _)
In srfi/srfi-1.scm:
    634:9 11 (for-each #<procedure 7f5a20eda4e0 at guix/scripts/ref…> …)
In guix/scripts/refresh.scm:
   309:22 10 (update-package _ #<package python-pytorch@1.11.0 gnu/…> …)
In guix/upstream.scm:
   475:10  9 (package-update/git-fetch _ _ #<<upstream-source> pack…> …)
In guix/git.scm:
    550:8  8 (latest-repository-commit #<store-connection 256.99 7f…> …)
    472:7  7 (update-cached-checkout _ #:ref _ #:recursive? _ # _ # _ …)
In srfi/srfi-1.scm:
    634:9  6 (for-each #<procedure 7f5a265c7f30 at guix/git.scm:321…> …)
In guix/git.scm:
   333:20  5 (_ _)
In srfi/srfi-1.scm:
    634:9  4 (for-each #<procedure 7f5a266631e0 at guix/git.scm:321…> …)
In guix/git.scm:
   325:16  3 (_ _)
In git/bindings.scm:
     77:2  2 (raise-git-error _)
In ice-9/boot-9.scm:
  1685:16  1 (raise-exception _ #:continuable? _)
  1685:16  0 (raise-exception _ #:continuable? _)

ice-9/boot-9.scm:1685:16: In procedure raise-exception:
Git error: failed to resolve path 
'/home/ludo/.cache/guix/checkouts/orwu3gj6brdg2ui6r2tl5me7plucokpvqvgbhe2yuo6jc2tovvha/third_party/gloo/third-party/googletest/.git':
 No such file or directory
$
$ ls 
/home/ludo/.cache/guix/checkouts/orwu3gj6brdg2ui6r2tl5me7plucokpvqvgbhe2yuo6jc2tovvha/third_party/gloo/third-party/
ls: cannot access 
'/home/ludo/.cache/guix/checkouts/orwu3gj6brdg2ui6r2tl5me7plucokpvqvgbhe2yuo6jc2tovvha/third_party/gloo/third-party/':
 No such file or directory
$ ls 
/home/ludo/.cache/guix/checkouts/orwu3gj6brdg2ui6r2tl5me7plucokpvqvgbhe2yuo6jc2tovvha/third_party/gloo/
cmake/          CODE_OF_CONDUCT.md  docs/  LICENSE    tools/
CMakeLists.txt  CONTRIBUTING.md     gloo/  README.md
$ ls 
/home/ludo/.cache/guix/checkouts/orwu3gj6brdg2ui6r2tl5me7plucokpvqvgbhe2yuo6jc2tovvha/third_party/gloo/.gitmodules
 
/home/ludo/.cache/guix/checkouts/orwu3gj6brdg2ui6r2tl5me7plucokpvqvgbhe2yuo6jc2tovvha/third_party/gloo/.gitmodules
--8<---------------cut here---------------end--------------->8---

Ludo’.