Trying to contribute packages: ./pre-inst-env doesn't work

[Doron Behar <doron.behar@gmail.com>]

Hey all,

Coming from Arch Linux, I'm trying to add new packages and contribute
them to the Guix project. However, I have a few doubts as for dictating
a workflow and most importantly I can't seem to be able to actually test
my new packages' definitions with `./pre-inst-env`.

First of all, I'm not sure whether I should define custom channels or
not. After reading the section Channels in the manual, it seemed
reasonable for me that in order to test my fork of Guix, I should create
a branch with my new packages and then test it with `guix pull` and
`guix build`. But `guix search` and `guix build` don't seem to be able
to find the new packages I defined and I couldn't find a way to debug
this.

To be more specific, I've tried this idea by writing the following in
`~/.config/guix/channels.scm`:

(list (channel
        (name 'guix)
        (url "file:///var/code/doron/guix")))

I ran `guix pull` and it seems it checked out my version of Guix but it
make those new packages available.

-----

Failing to achieve my target with custom channels, I've disabled the
custom channels I configured above and I tried following the
Contributing section in the manual. I jumped straight to the Packaging
Guidelines section and I've done the following:

- I ran ./configure inside /var/code/doron/guix
- I killed the systemd service of guix-daemon and I ran this command:
  `sudo -E ./pre-inst-env guix-daemon --build-users-group=guixbuild`
- In another shell, I tried running:
  `./pre-inst-env guix build my-new-package`

But it reports that the package `my-new-package` is unknown.

-----

Failing to do that and after looking for alternative ways to create new
packages, I read about the `--load-path` option of `guix build`. Is it
possible to use it for new packages testings? I tried to run the
following but I got all kinds of warnings and errors:

guix build -L/var/code/doron/guix my-new-package

Here is all of the output:
https://gist.github.com/doronbehar/38d31142522fd01a67e7da412b0cf5ed

Since there were all of these "source file newer than compiled"
messages, I tried putting back my channels configuration from above and
run `guix pull` again but I got pretty much the same errors and
warnings.

-----

Any way, I'm very frustrated. Although I'm very excited as for the
genius design of Guix and it's flexibility and extensibility, I'm very
disappointed by it's UX for a simple thing as package contribution. but
this should be addressed in a separate discussion.

I hope someone could help me.

Thanks, Doron.