Questions regarding substitutes with debug output

[Olivier Dion via <help-guix@gnu.org>]

Hi,

I require debugging symbols of multiple packages.  Some of them already
have a debug output from the main guix channel, but others don't.  So
I had in mind to make a channel and publish the substitutes with the
debug outputs.

Regarding this specific case, I have a question:

  Let's say I need firefox:out + firefox:debug.  My channel does provide
  these outputs, guix's main channel only provides the firefox:out.

  I need to specify the package programmatically as a string in Guile.
  More specifically in the process packages field of Guix Workflow Language.

  How could I make sure that Guix use my version of Firefox over the one
  defined by the main channel?  My guess is to change the name of my
  package to something like "my-firefox".  But it would be nicer if I
  don't have to do so.  Perhaps there's a way to force channel
  preference?

  I know that we can specify version like "firefox@99" but what about
  outputs?  Is it possible to do (list "firefox:out" "firefox:debug").?

Regards,
old

-- 
Olivier Dion
oldiob.dev