feat: introduce nixpkgsNix, set nix version to 2.20; chore: bump nix-darwin and fix darwin deploy script

[steveej]

deployed to

• linux-builder-01
• macos-01 currently broken
• macos-03:¹
• macos-06: ¹
• macos-02 ²
• macos-05 ²

postponing due to unavailability:

• macos-04: cannot login: ssh is asking for a password. tracking in macos-04: cannot login: ssh is asking for a password #97

postponing these until #68 is resolved. these are not involved with the holochain CI nix builds, thus they only need nix to build their own system derivation.

• dweb-reverse-tls-proxy
• turn-0
• turn-1
• turn-2
• turn-3

potentially fixes holochain/holochain#3556.

Footnotes

1. could only get to 2.19 at first as 2.20 would show: error: 'show-config' is a deprecated alias for 'config show'. was held back by the lack of flake(inputs/nix-darwin): use upstream instead of fork #91 until i rebased that in 11db2c4. ↩ ↩²

2. @peeech @alastairong any contraindications for deploying this on our shared darwin machines? ↩ ↩²

[r-vdp]

Seems ok to me. But I'm not much in favour of having multiple nixpkgs instances.

24.05 will be released in two weeks and will contain this nix version, so if we merge this, I would propose to update to 24.05 as soon as possible and get rid of the separate nixpkgs instance again.

[steveej]

@r-vdp

Seems ok to me. But I'm not much in favour of having multiple nixpkgs instances.

so there are no foreseeable side-effects of upgrading nix to v2.20 on the darwin machines that are used as builders by Holo's hydra instance?

[r-vdp]

Barring any bugs, the nix builder protocol is versioned, so it's usually fine to have different versions of the daemons talk with each other.

I couldn't look through the code a lot from my phone, are we upgrading nix on the Mac builders but not on hydra? Because they are managed by different repos?

[steveej]

I couldn't look through the code a lot from my phone, are we upgrading nix on the Mac builders but not on hydra? Because they are managed by different repos?

yes, that's the case.

[steveej]

Barring any bugs, the nix builder protocol is versioned, so it's usually fine to have different versions of the daemons talk with each other.

based on this i'm going ahead with the update on those builders.