bug#54779: guix home reconfigure throw error after Shepherd updata

[Ludovic Courtès]

Hi,

Aleksandr Vityazev <avityazev@posteo.org> skribis:

> guix home reconfigure config.scm [1], throw error and freezes even
> ctrl-c doesn't help

Indeed, this can be reproduced like so:

--8<---------------cut here---------------start------------->8---
$ herd load root /gnu/store/1xx98q22c6ijr0p5pjbq3wnxd5yyxlmy-shepherd.conf
WARNING: Use of `load' in declarative module (#{ g139}#).  Add #:declarative? 
#f to your define-module invocation.
Uncaught exception in task:
In fibers.scm:
    150:8  9 (_)
In ice-9/boot-9.scm:
  1747:15  8 (with-exception-handler #<procedure 7f52c6b31390 at ic…> …)
In shepherd.scm:
    432:9  7 (_)
In ice-9/boot-9.scm:
  1747:15  6 (with-exception-handler #<procedure 7f52c6b312d0 at ic…> …)
In ice-9/exceptions.scm:
   406:15  5 (_)
In ice-9/boot-9.scm:
  1752:10  4 (with-exception-handler _ _ #:unwind? _ # _)
In shepherd.scm:
   502:23  3 (_)
In srfi/srfi-1.scm:
   586:17  2 (map1 (#<<service> 7f52c8f77f30>))
In ice-9/boot-9.scm:
  1685:16  1 (raise-exception _ #:continuable? _)
  1683:16  0 (raise-exception _ #:continuable? _)
ice-9/boot-9.scm:1683:16: In procedure raise-exception:
Zero values returned to single-valued continuation
--8<---------------cut here---------------end--------------->8---

(‘guix home reconfigure’ invokes the same command as above.)

The problem is that ‘start-in-the-background’ returns zero values, as
indicated above, but shepherd expects user commands to return one value.

So the fix, as you suggest, is to return one value at the end of
shepherd.conf.

You suggested redirecting stdin, which is also a good idea, but for a
different reason.  :-)  Anyway I’ve done both.

  dd2ab92d9d home: shepherd: Redirect input port to /dev/null.
  bc867b2ab0 home: shepherd: "shepherd.conf" returns one value.

Thank you!

Ludo’.