Compared to the rest of the runtime, the eval via nix-env takes the longest time when uncached.
It'd be nice if two checkouts could be made with two nix-env evals in parallel to speed this up.
This would also catch merge conflicts early; you currently have to wait through a lengthy eval before it's even attempted.
It might have to be disabled by default due to memory constraints (or based on available host memory) but 2x6GiB isn't too much to ask for nowadays.
That would also require to have both nixpkgs trees checked out at the same time. I could check if https://github.com/nix-community/nix-eval-jobs could improve things here as it also deals with memory consumption.
Compared to the rest of the runtime, the eval via nix-env takes the longest time when uncached.
It'd be nice if two checkouts could be made with two nix-env evals in parallel to speed this up.
This would also catch merge conflicts early; you currently have to wait through a lengthy eval before it's even attempted.
It might have to be disabled by default due to memory constraints (or based on available host memory) but 2x6GiB isn't too much to ask for nowadays.