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oxalica / rust-overlay

Pure and reproducible nix overlay of binary distributed rust toolchains
MIT License
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Flake templates #188

Open ScratchCat458 opened 2 months ago

ScratchCat458 commented 2 months ago

In response to issue #119.

Adds a new example to the examples folder that provides a flake with a dev shell with the default stable toolchain and allows use on multiple systems via flake utils. Based on this README example.

Template can be initialised with:

nix flake init -t github:oxalica/rust-overlay

I'm considering creating another template that uses a rust-toolchain.toml instead, but I will save that for another pull request.

oxalica commented 2 months ago

I personally cannot get the point of flake template until it gets anything more than a fancier cp -r. It does not even support configuring name, let alone custom checks and file appending. Guessing user's demand is hard, even providing multiple templates cannot make up the inability of cp -r.

  1. Is user already having a Git Repository and/or a rust package, just want to initialize the Nix part? Does .gitignore exists and target ignored?
  2. Is flake.nix and/or shell.nix already exists? Which approach does the user prefer? I'm a fan of flakes, but I still find shell.nix more light-weight and more convenient for simple cases. It's fast and does not copy the whole directory into nix store after each modification.
  3. Does the user want to use rust-overlay for building and/or packaging in Nix, or for development, or both? For packaging or CI, I'd say the best practice is to have 3rd party tools like naersk or crane to cache dependencies, but I don't want to endorse them and add them as "default template". Same thing for flake-utils, flake-parts and many other structure helpers. You may want them in some (or many) cases, but adding them into template is not a good way to introduce them.
  4. Cross compilation is also a hard part. The different between targeting aarch64-linux and riscv64-linux may not be just a string change. (Through, in most cases, they are; unless the user is not in the set of "most cases")

I prefer adding more examples if user want something for reference, than flake templates for directly cp. Or maybe you have better knowledge on "what a most useful template for most users is like"?

ScratchCat458 commented 2 months ago

Nix's templates are somewhat limited in what they can provide due to a lack of granularity. There has been some ideation, but its mostly a dead end. I agree that Crane is probably the best option for most users to setup shells alongside packaging. There is no real consistency across the templates of different repos, some initialise the entire project, others only create the flake. For most users, a nix flake init is usually desired as a replacement for a quickstart. I can definitely see the difficulty in providing a template that satisfies most use cases for a lower-level tool like rust-overlay, especially after considering cross compilation.

Sorry that I can't really provide a satisfying answer.