nix repl: Mark as experimental

[edolstra]

Fixes #5604.

[bjornfor]

Bring back 'nix-repl' then?

[edolstra]

@bjornfor You mean as a separate project?

[bjornfor]

@bjornfor You mean as a separate project?

It doesn't really matter to me, but as a NixOS user I wonder about this chain of events:

1. Use nix-repl.
2. nix-repl is removed, replaced by nix repl.
3. nix repl is marked as experimental -- no way to run a Nix REPL without opt-in to unstable/experimental Nix.

It feels like we just lost the ability to run a Nix REPL.

[thufschmitt]

I agree with @bjornfor’s concerns . Contrary to the other nix commands, nix repl is the only interface to something that isn’t possible with the old cli anymore (not counting the now defunct nix-repl). So if it becomes experimental, there should be a replacement.

I don’t know whether it’s worth adding a nix-repl command just for the sake of keeping the whole nix command experimental or whether it’s fine to just keep it as-it-is (esp. given that there’s other non-experimental nix subcommands like doctor or upgrade-nix).

[stale]

I marked this as stale due to inactivity. → More info

[Ericson2314]

Has the ship sailed on this?

[fricklerhandwerk]

Triaged in Nix maintainers meeting:

• @Ericson2314: can't make it experimental any more, it's stable and widely used
• @thufschmitt this is the only new nix command that is not guarded by an experimental feature flag but where we know we want to make changes
  • @fricklerhandwerk: sigh

[nixos-discourse]

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/2023-06-30-nix-team-meeting-minutes-67/29835/1