Flakes/Nix3.0 issues

Development
10

After using flakes for a month or two, here are my annoyances as an end user:

  1. While there is nice support with flakes for building on different systems (x86_64-linux, aarch64-linux, etc), there is no built-in support for cross-compiling, or easily specifying the system you want to cross-compile to.

    [flakes] Where do cross compiled packages go? · Issue #5157 · NixOS/nix · GitHub

    At work we worked around this by specifying both native packages and cross compiled packages as different packages exposed by our flake, but it feels somewhat hacky.

  2. There is no good way to pass options to flakes: Passing options to flakes

    This seems like a really big blow to usability. Judging from that thread, it seems like passing options to nix-build is a relatively common thing to do.

  3. The nix registry stuff seems like it is nice, but by default it doesn’t pin nixpkgs to a specific commit (or even a Hydra channel). This means if you do something like nix shell nixpkgs#foo, it is possible you have to build from source, and you may just have to download the latest Nixpkgs master every time.

    I created a thread explaining how to pin to a commit on one of the channels, but I feel like something like this should be done by default: How to pin nix registry nixpkgs to release channel

  4. nix flake show doesn’t handle IFD in a graceful way: Don't allow IFD in flakes by default by edolstra · Pull Request #5253 · NixOS/nix · GitHub

    Instead of immediately failing out when reaching IFD, it would be great if nix flake show instead displayed an error message only for those attributes that require IFD, but continued on showing the rest of the attributes defined in the flake.

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