This change simplifies installing yaxg in a nix environment from nix-env -i yaxg-unstable to just nix-env -i yaxg.

Pretty sure that is already the case, since the -i flag expects a pkgname. The version is not part of that.

❯ nix-build -A yaxg-unstable
error: attribute 'yaxg-unstable' in selection path 'yaxg-unstable' not found
❯ nix-build -A yaxg
/nix/store/dfvybj89l9xn4vyvy8v3gmps3l89x8qc-yaxg-unstable-2018-05-03

I've seen the unstable prefix in the version attribute whenever there was no tagged release. So I'm not sure this change is actually necessary.

Pretty sure that is already the case

no it's not, nix-build's syntax is not consistent with nix-env:

$ nix-env -i yaxg
error: selector 'yaxg' matches no derivations

working commands:

$ nix-env -i yaxg-unstable
$ nix-env -iA nixpkgs.yaxg

nix-env -i doesn't read the pname and search against it, instead it takes the full name and strips the version with something like /-[0-9-]*$/d.

nix-env -i yaxg is shorter than either of these, and doesn't give the feeling of installing unstable software. needing to append -unstable makes me as a user feel like I'm installing a beta version, like firefox-beta or something-git. To me, the existence of the postfix -unstable implies that the software has an alternative stable version, is undergoing rapid changes, or is very new. None of these are true for yaxg anymore.

Anyways, I just remembered it's actually in the nixpkgs manual that you should add -unstable to the name of "non releases". It also says the version should always start with a number. So technically -unstable should be moved from the version to the name.
https://nixos.org/nixpkgs/manual/#sec-package-naming

Considering yaxg really is stable, maybe I'll bug upstream to tag this as 1.0 or something.

nix-env without -A is not really recommended since it needs to scan the whole nixpkgs for package with matching name. We really need to remove it from docs. I would suggest adding alias npkge=nix-env -f '<nixpkgs>' or alias npkge=nix-env -f channel:nixpkgs-unstable and then using npkge -iA yaxg if you find the fully qualified command too long.

Yeah, where to put unstable in the name is point of contention since the name splitting is not a very good design, see the discussion in #88023 (comment).

Yeah I already made a little bash function that I use, but it's a bit more hacky: nixi() { nix-env -iA nixpkgs.$@; }. May adopt that one, thanks.

Anyways since it seems the rest of nixos uses -unstable in this way I'll close this issue. Maybe I'll bug upstream to make a tag if it's really necessary.