[bug#28706] [PATCH 0/3] Detect wrong UUIDs/labels in 'guix system init/reconfigure'

[Ludovic Courtès]

Hello Guix!

At the GHM we were discussing that a common mistake when installing
GuixSD is to specify a wrong file system UUID or label in the config.
You would run the whole install to completion, reboot into the new
system, just to find that it fails to boot because you passed the wrong
UUID or label.  And then you have to reinstall again.  Roel’s report at
<https://lists.gnu.org/archive/html/help-guix/2017-09/msg00068.html> is
another instance of that (though Roel could easily roll back in that
case.)

With this patch such mistakes are detected early on, upon ‘guix system
init’ or ‘guix system reconfigure’:

  configuration.scm:32:23: error: file system with UUID 
'c78e0703-373f-4c4d-9652-5633f072eae6' not found
  configuration.scm:42:23: error: file system with UUID '1234-ABCD' not found

The behavior is to stop altogether when such a problem is found.  I
wondered whether it should be a warning instead, on the grounds that it
could be annoying if the mistake-prevention logic wrongfully raised an
error for some reason.  However, I figured that a warning would be much
less efficient (people wouldn’t notice), and I think
‘check-file-system-availability’ avoids the obvious pitfalls by
filtering out irrelevant file systems.

Thoughts?

Thanks,
Ludo’.

Ludovic Courtès (3):
  uuid: Add 'uuid=?' and use it.
  file-systems: Add a 'location' field to <file-system>.
  guix system: Error out when passed a wrong file system UUID/label.

 gnu/build/file-systems.scm  |  4 +--
 gnu/system/file-systems.scm |  6 ++++-
 gnu/system/uuid.scm         | 13 +++++++++
 guix/scripts/system.scm     | 65 +++++++++++++++++++++++++++++++++++++++++++++
 tests/uuid.scm              |  6 +++++
 5 files changed, 91 insertions(+), 3 deletions(-)

-- 
2.14.2