Exact Versions and Guix Dev Tooling

[jgart]

Hi,

What's the Guix approach to getting exact versions for a dev project.

Should we be contributing those packages upstream or should Guix just
provide the tooling to generate exact package definitions for exact
versions that are needed in a particular project?

For example, what if a dev needs the versions of every library you're
using in a development project and they are not in Guix?

What is Guix's answer to that? Do they have to package everything and
wait for it to get merged to the master branch?

I'm nodding to tools like these in the Nix community:

# PureScript

https://github.com/purs-nix/purs-nix
https://github.com/justinwoo/spago2nix
https://github.com/nix-community/poetry2nix

# Node

https://github.com/nix-community/npmlock2nix
https://github.com/svanderburg/node2nix
https://github.com/serokell/nix-npm-buildpackage

# Rust

https://github.com/kolloch/crate2nix
https://github.com/oxalica/rust-overlay
https://github.com/nix-community/fenix

Is our approach currently that if you develop with Guix you have to
develop against the versions that are in Guix master or some other branch?

WDYT