bug#46650: Extending package transformation options

[Leo Famulari]

On Fri, Feb 19, 2021 at 06:24:57PM -0500, Carl Dong wrote:
> One of the main reasons for switching over to Guix is for its 
> bootstrappbility and the ability to perform `--bootstrap --no-substitutes` 
> builds. As mentioned in the gnutls ticket, performing these source-based 
> builds can sometimes reveal problems with tests suites:
> 1. Spurious tests
> 2. “Expiring” tests (like the gnutls one)
> 3. Foreign distro problems (0zmcam9sdiag9s1qx3xvlf8a3jnm53x2-sed-4.8.drv 
> fails to build on SELinux-based distros because of a test failure in 
> testsuite/inplace-selinux)

I hate to throw a wrench in your plans, but I think that using package
transformation options on the command-line militates against many of the
benefits you are seeking to take advantage of, in terms of an
introspectable and bootstrappable software system.

Normally when using Guix, our Git tree provides a convenient and
comprehensive view of the entire software system. It also provides an
entry point into the system for making changes.

When using these command-line package transformations, you diverge from
the Guix Git tree and enter uncharted and untracked territory. If you
install some software or build some system using these transformations,
there is no Git tree you can check out and begin exploring. For example,
there will be no package definition of GnuTLS-without-tests that can be
referred to and shared.