@marsam you might be interested by this.
I think this is a good idea, however, many packages using the default nodejs might break with this.
Not sure what is the best way to do this. Wait for the 21.11 release then merge ?
Should we try to contact individual nodejs packages maintainers ?
I think the main problem here will be node-packages, If I'm not wrong, node2nix will break with node 16.

Unfortunately, we can't upgrade to 16.x because we are blocked by node2nix #132456

Could we just use node_14 with all the node2nix packages ?
Just to unblock the others, since it doesn't seem likely that node2nix will receive any major update soon.

@happysalada I like your suggestion, so I added a commit. Let me know if that's what you had in mind.

That is what I had in mind.
Doing a brief search, I see that many people in their nixos modules use pkgs.nodejs without specifying the version. Those are likely to break. This should wait until the 21.11 release, but after that, It seems good to me. (I'll have time to think about this, I will update if I find anything).
@billewanick we have to remember to fix the nodejs version for lemmy-ui.

It's been fixed for node2nix: svanderburg/node2nix@e73c616

We could do an unstable release of node2nix, but I feel it's better to keep what we have and change when node2nix makes a new release.

#144627 (comment) mentions that the branch off happened already. Is it time to revisit this?

btw, there is an update in progress of node2nix https://github.com/NixOS/nixpkgs/pull/146440/files
but yeah I think this can potentially be merged to staging. Whenever there is time to rebase and fix the conflict, I personally think this is mergeable, unless anyone sees an objection that I have missed.

Rebased

I just noticed, node16 fails to build on aarch64-darwin. @marsam is this normal or is this just a transitive failure ? (no worries if you don't know). Given that nixos supports darwin on tier1, we can't just merge this then ? (let me know if I'm wrong).

@happysalada it builds just fine on master branch:

• https://hydra.nixos.org/eval/1725069?filter=nodejs&compare=1724929&full=#tabs-still-succeed

@bobrik thanks for checking this out. Let's merge then.

This PR cause this regression #152745 As far as I know we still lack support for nodejs 16 in node2nix which makes me wonder - What was tested before merge here? I have a feeling there might be more things broken at the moment.

I thought the latest version of node2nix supports node 16 (version 1.10). There is a current PR to regenerate and test nodePackages #146440 (still WIP).
Since it was impossible to test all the packages, if I remember correctly nodePackages were tested. We indeed missed elmPackages indeed.
I personally use

      nodePackages.prettier
      nodePackages.pnpm
      nodePackages.node2nix
      nodePackages.npm-check-updates
      nodePackages.svelte-language-server
      nodePackages.yarn

and those work like a charm.

We indeed missed elmPackages

don't worry about that. It's intentionally designed in a way it doesn't block work on other parts of nixpkgs. I'm happy to take care of it. That's being said I think there might be other packages which rely on expressions produced by node2nix using nodejs argument which might need updating. It's not just nodePackages (which are btw independent of what is defined as nodejs in nixpkgs so I think they don't even use node 16 but I might be mistaken) - there can be applications using node2nix for packaging and using nodejs argument.

Anyway I think we can deal with all the potential issues if there are any.

To clarify. I think that if intention of this PR was to update nodejs version things defined within nodePackages are using I don't think it accomplished that. This updated nodejs version for everything which uses nodejs attribute directly but I think nodePackages are using explicit attribute name which was updated in #149120 to version 14. Anyway take this with grain of salt - I did not check the code base this is just based on my memories of working with that part of nixpkgs about a year ago.

In order to update nodejs version for things that use node2nix we need to wait for support upstream. Current highest version node2nix supports is 14. However this should update nodejs for derivations that don't depend on node2nix (don't use npm dependecies, just node).