Subject: [bug#28600] [PATCH] tests: install: Switch to modifying the gc-root-service-type.

From: [email-masked] (Ludovic Courtès)
Date: Tue, 26 Sep 2017 09:46:10 +0200

Hi!

Christopher Baines <[email-masked]> skribis:

> Rather than adding the service to the system.
>
> The previous approach is causing the system tests to fail, as the os already
> contains a service of type gc-root-service-type, and the way that this service
> extends the system-service doesn't compose, causing an error if its added
> twice.
>
>   ERROR: In procedure symlink: File exists

Good catch!

> * gnu/tests/install.scm (operating-system-with-gc-roots): Modify the existing
>   gc-root-service, rather than adding another.
> ---
>  gnu/tests/install.scm | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/gnu/tests/install.scm b/gnu/tests/install.scm
> index 49743860e..28dfc3b8b 100644
> --- a/gnu/tests/install.scm
> +++ b/gnu/tests/install.scm
> @@ -127,8 +127,9 @@
>    "Return a variant of OS where ROOTS are registered as GC roots."
>    (operating-system
>      (inherit os)
> -    (services (cons (service gc-root-service-type roots)
> -                    (operating-system-user-services os)))))
> +    (services
> +     (modify-services (operating-system-user-services os)
> +       (gc-root-service-type _ => roots)))))

What about:

  (services (cons (simple-service 'extra-root
                                  gc-root-service-type roots)
                  (operating-system-user-services os)))

This would make sure there’s always a single ‘gc-root-service-type’
instance, and we’re just extending it with additional roots, rather than
overriding what it does.

I can push that if it works for you.

Thanks,
Ludo’.