riff VS rust-overlay

Dependency inference for Rust packages using the Riff registry and python projects

- Dependency inference for Rust packages using the [Riff](https://github.com/DeterminateSystems/riff) registry and python projects

In this language context specifically, if one wanted to manage their workspace with Nix I would reach for Riff and/or oxalica/rust-overlay first, since they are deliberately more aware of Rust-specific nuance. In the latter's case it has compatibility paths with rustup-toolchain files as well, for allowing your peers who can't or won't adopt Nix to continue to feel like first-class participants in the project. Another alternative I don't have experience with would be nix-community/fenix.

Seems to have spiritual overlap with what I understand the goals of Riff to be. Both projects are early stage and not able to cover every language ecosystem yet.

No, I wouldn't say that's obvious. Riff doesn't need 100% buy-in from all Rust maintainers because not all Rust projects have external dependencies. But what we've found in our research on the crate ecosystem is that there are particularly busy "nodes" in the dependency graph. Each time a busy "node" with external dependencies adds a few lines to Cargo.toml, that un-breaks a number of downstream project builds. Our internal registry is pretty small but even that has substantially increased the % of projects in which riff run cargo build works without issue. It's an asymptotic approach and we're confident that sufficient awareness could get us pretty darned close.

We currently have a hard-coded [registry](https://github.com/DeterminateSystems/riff/blob/main/registry/registry.json) of some known per-crate dependencies. But the goal is less to hard-code ever more dependencies and more to convince maintainers to explicitly [declare dependencies](https://github.com/determinateSystems/riff#how-to-declare-package-inputs) in their `Cargo.toml` under `package.metadata.riff`. Because Riff uses `cargo metadata` for the entirety of the crate dependency graph, explicit dependency declarations actually benefit downstream crates as well.

I'm trying to understand overlays in order to make a proper rustup install (I've read that this overlay is the best way to go).

real-world example: https://github.com/oxalica/rust-overlay/blob/master/flake.nix

In this language context specifically, if one wanted to manage their workspace with Nix I would reach for Riff and/or oxalica/rust-overlay first, since they are deliberately more aware of Rust-specific nuance. In the latter's case it has compatibility paths with rustup-toolchain files as well, for allowing your peers who can't or won't adopt Nix to continue to feel like first-class participants in the project. Another alternative I don't have experience with would be nix-community/fenix.

p.s. I'm not sure if it's mentioned much of anywhere, but it'd be neat if there was a way to figure out the appropriate cargo from a rust-toolchain/rust-toolchain.toml if present, ala https://github.com/oxalica/rust-overlay. Funnily enough 95% of my development time is in Rust, but I don't actually have it installed globally, fun times being a NixOS user. I'd definitely make the argument that cargo is an external dependency!

Many of us have moved to https://github.com/oxalica/rust-overlay over Mozilla's overlay.

We added rust-overlay, so we can easily specify different rust versions without relying on nixpkgs to give us what ever rust version in there.

If it's Rust, you can use https://github.com/oxalica/rust-overlay to get any version you want very easily without pinning an instance of nixpkgs just for it.

asdf does not allow you to keep three different versions of the same language, so I'm not sure how that compares? It's not super-trivial to do in Nix, but at least you can do it.

asdf is also no different than Nix when it comes to minor/major versions. You're at the mercy of what the plugin does, other than that you have to create your own plugin from scratch or make a fork. Nix has the option to patch things up more easily at least.

How does this compare to https://github.com/oxalica/rust-overlay/ ? Can fenix ingest a rust-toolchain file and provide packages from it?

Can you say a bit about how this compares to oxalica’s rust overlay?

I frequently try to do something, say use (from the README of rust overlay):