Subject: Re: bug#41569: build systems cannot set default outputs other than "out"

From: Ludovic Courtès <[email-masked]>
Date: Sun, 31 May 2020 23:16:07 +0200

Hi,

Ricardo Wurmus <[email-masked]> skribis:

> For the haskell-build-system I want to offer two outputs by default:
> "out" and "static".  However, the build system has no way to override
> the default as (@ (guix packages) package->bag) passes the package’s
> “outputs” value to make-bag.

Ah.

> When the package doesn’t define a value for “outputs”, the default
> '("out") is used.  I suggest removing the default value from the
> <package> record, so that the build system defaults have a chance.

Problem is, we don’t want to add an ‘outputs’ line to each and every
package definition.  So how can we deal with that?

We could have a special trick where ‘outputs’ defaults to a special
value and ‘package-outputs’ actually asks the build system what the
default outputs are.

Thoughts?

Ludo’.