Subject: Re: [bug#59983] [PATCH] home: Let user configure XDG base directories.

From: Andrew Tropin <[email-masked]>
Date: Tue, 13 Dec 2022 08:25:16 +0400

On 2022-12-12 03:00, Antero Mejr via Guix-patches via wrote:

> * gnu/home.scm (home-environment)[base-xdg-configuration]: New field.
> * gnu/home/services/xdg.scm (ensure-xdg-base-dirs-on-activation): Make
> XDG_RUNTIME_DIR directory if the configuration changes it from the default.
> ---
> Allows making a runtime dir at ~/.local/runtime (or any other dir),
> so users don't have to set up elogind or other greeters/PAM modules.
>
>  gnu/home.scm              | 9 +++++++--
>  gnu/home/services/xdg.scm | 7 ++++++-
>  2 files changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/gnu/home.scm b/gnu/home.scm
> index c95d1e0818..f100b575e3 100644
> --- a/gnu/home.scm
> +++ b/gnu/home.scm
> @@ -39,6 +39,7 @@ (define-module (gnu home)
>              home-environment-essential-services
>              home-environment-services
>              home-environment-location
> +            home-environment-base-xdg-configuration
>  
>              home-environment-with-provenance
>  
> @@ -71,7 +72,10 @@ (define-record-type* <home-environment> home-environment
>    (location           home-environment-location            ; <location>
>                        (default (and=> (current-source-location)
>                                        source-properties->location))
> -                      (innate)))
> +                      (innate))
> +
> +  (base-xdg-configuration home-environment-base-xdg-configuration
> +                          (default (home-xdg-base-directories-configuration))))
>  
>  (define (home-environment-default-essential-services he)
>    "Return the list of essential services for home environment."
> @@ -83,7 +87,8 @@ (define (home-environment-default-essential-services he)
>     (service home-symlink-manager-service-type)
>  
>     (service home-fontconfig-service-type)
> -   (service home-xdg-base-directories-service-type)
> +   (service home-xdg-base-directories-service-type
> +            (home-environment-base-xdg-configuration he))

This change is not needed, you can set xdg dirs by extending
home-xdg-base-directories-service-type with adjusted
home-xdg-base-directories-configuration.

>     (service home-shell-profile-service-type)
>  
>     (service home-service-type)
> diff --git a/gnu/home/services/xdg.scm b/gnu/home/services/xdg.scm
> index 865f8b81d7..b62580461e 100644
> --- a/gnu/home/services/xdg.scm
> +++ b/gnu/home/services/xdg.scm
> @@ -133,7 +133,12 @@ (define (ensure-xdg-base-dirs-on-activation config)
>                          (configuration-field-name field) 'upper))))
>                   ;; XDG_RUNTIME_DIR shouldn't be created during activation
>                   ;; and will be provided by elogind or other service.
> -                 (and (not (string=? "XDG_RUNTIME_DIR" variable))
> +                 ;; But if the user changes the value from the default,
> +                 ;; then we can make XDG_RUNTIME_DIR.
> +                 (and (or (not (string=? "XDG_RUNTIME_DIR" variable))
> +                          (not (string=? ((configuration-field-getter field)
> +                                          config)
> +                                         "${XDG_RUNTIME_DIR:-/run/user/$UID}")))
>                        variable)))
>               home-xdg-base-directories-configuration-fields)))

There is no way to understand upfront if directory containing
XDG_RUNTIME_DIR is writable and this is why it's a good idea to delegate
initialization of it to external thing and never try to create it here,
even if it has non-default value.

But in case you are sure it's writable and want to ensure the directory
created, just be this thing managing and providing XDG_RUNTIME_DIR and
extend activation script with the following G-expression:

#~(mkdir-p (getenv "XDG_RUNTIME_DIR"))

The full snippet:

--8<---------------cut here---------------start------------->8---
(simple-service
 'ensure-xdg-runtime-dir-exists
 home-activation-service-type
 #~(mkdir-p (getenv "XDG_RUNTIME_DIR")))
--8<---------------cut here---------------end--------------->8---

-- 
Best regards,
Andrew Tropin