rules_cc VS rules_rust

Not that I'd recommend it, but if you symlink your system library into the bazel build area, as long as your sandboxing setup don't hose you (or you just turn it off), bazel will track system tools/library in the same way as everything else.

Bazel's rules_cc even has a system_library.bzl you can import a `system_library` from that automates this for you. https://github.com/bazelbuild/rules_cc/blob/main/cc/system_l...

I'd still recommend building everything from scratch (and understanding the relationships and graph of your dependencies), but if your build isn't that complicated and you want to role the dice on UB, this isn't that hard.

As an aside, the most galling part of bazel's cache key calculations has to be that it's up to the individual rules to implement this how they see fit. The rules native to bazel written in java vary wildly compared to starlark-written rules. On thing you (or someone in your org) end up becoming pretty comfortable with while using bazel in anger is RTFC.

I found several associated issues and a closed PR that supposedly solved this issue. However, it seems that cc_rules has undergone several changes and this PR likely wouldn't function.

The same reason Bazel builds avoid using Cargo when building Rust software, so I'll describe why Bazel would do this:

- Bazel wants to cache remote resources, like each respective crate's source files.

- Bazel then wants to build each crate in a sandbox, and cache the build artifacts

This is an established practice, and Nix wants to drive the build for the same reasons.

See:

- https://github.com/bazelbuild/rules_rust

- https://github.com/google/cargo-raze

To answer your question, I don't know if Soong or Bazel can reuse the files produced by an incremental Rust compilation. I tried searching the rules_rust repository and found some discussions, but nothing that clearly told me "Yes, this is supported".

Bazel doesn't allow targeting a lot of platforms (especially embedded) from Rust, even when the Rust ecosystem supports these targets. Something is off with its design if new work needs to be done for every platform that's already available behind an interface that's as consistent as what rustc gives.

What is supported needs to be inferred from this file, as far as I can tell: https://github.com/bazelbuild/rules_rust/blob/main/rust/plat...

You might be overjoyed to learn that you can use a build tool that forces you to manually write out the dependencies between each file.

I am using rules_rust and have the VS Code Bazel plugin installed, but I am still not getting autocomplete.

Other than that, the performance of both for builds should be determined exactly by the organization of code into separate crates and the rustc invocations. Bazel generally encourages smaller crates, but that's very subtle. There is at least 1 case I can think of where rustc is overfit to cargo, in a way that is not easily replicable by bazel, which is the metadata/rlib pipelining https://github.com/bazelbuild/rules_rust/issues/228

Rust integrates pretty seamlessly into Bazel projects via rules_rust (https://github.com/bazelbuild/rules_rust). The existing rules even allow for c calling rust and rust calling c. Example: https://github.com/bazelbuild/rules_rust/blob/main/examples/...

With any compiled language you can use the compiler and vendor your dependencies instead of using the language's conventional package manager. For example, nothing prevents skipping Cargo and building Rust directly with rustc the way Bazel does.

https://github.com/bazelbuild/rules_rust