Replace xtask builds with build scripts

[tamird]

See individual commits.

Closes #22.
Closes #58.
Closes #96.
Closes #110.

[dave-tucker]

I was hoping to test this out - IIRC the main reason we used xtask was because build.rs could cause the rust-language-server to go bananas 🍌 (rebuilding the build script on every change).

After correcting the path to the bytecode, cargo build fails as follows:

$ cargo build       
   --> test-buildscript-hotness/src/main.rs:49:10
    |
48  | /     program.attach(&opt.iface, XdpFlags::default())
49  | |         .context("failed to attach the XDP program with default flags - try changing XdpFlags::default() to XdpFlags::SKB_MOD...
    | |         -^^^^^^^ method cannot be called on `Result<XdpLinkId, ProgramError>` due to unsatisfied trait bounds
    | |_________|
    |
    |
   ::: /home/dave/.cargo/registry/src/index.crates.io-6f17d22bba15001f/aya-0.13.0/src/programs/mod.rs:132:1
    |
132 |   pub enum ProgramError {
    |   --------------------- doesn't satisfy `_: StdError`
    |
   ::: /home/dave/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/result.rs:527:1
    |
527 |   pub enum Result<T, E> {
    |   --------------------- doesn't satisfy `_: Context<XdpLinkId, ProgramError>`
    |
    = note: the following trait bounds were not satisfied:
            `aya::programs::ProgramError: anyhow::context::ext::StdError`
            which is required by `Result<XdpLinkId, aya::programs::ProgramError>: anyhow::Context<XdpLinkId, aya::programs::ProgramError>`

error[E0277]: `?` couldn't convert the error to `anyhow::Error`
  --> test-buildscript-hotness/src/main.rs:38:8
   |
38 |     )))?;
   |        ^ the trait `From<EbpfError>` is not implemented for `anyhow::Error`, which is required by `Result<(), _>: FromResidual<Result<Infallible, EbpfError>>`
   |
   = note: the question mark operation (`?`) implicitly performs a conversion on the error value using the `From` trait
   = help: the following other types implement trait `FromResidual<R>`:
             <Result<T, F> as FromResidual<Result<Infallible, E>>>
             <Result<T, F> as FromResidual<Yeet<E>>>
   = note: required for `Result<(), anyhow::Error>` to implement `FromResidual<Result<Infallible, EbpfError>>`

error[E0277]: `?` couldn't convert the error to `anyhow::Error`
  --> test-buildscript-hotness/src/main.rs:46:20
   |
46 |         .try_into()?;
   |                    ^ the trait `From<aya::programs::ProgramError>` is not implemented for `anyhow::Error`, which is required by `Result<(), _>: FromResidual<Result<Infallible, aya::programs::ProgramError>>`
   |
   = note: the question mark operation (`?`) implicitly performs a conversion on the error value using the `From` trait
   = help: the following other types implement trait `FromResidual<R>`:
             <Result<T, F> as FromResidual<Result<Infallible, E>>>
             <Result<T, F> as FromResidual<Yeet<E>>>
   = note: required for `Result<(), anyhow::Error>` to implement `FromResidual<Result<Infallible, aya::programs::ProgramError>>`

error[E0277]: `?` couldn't convert the error to `anyhow::Error`
  --> test-buildscript-hotness/src/main.rs:47:19
   |
47 |     program.load()?;
   |                   ^ the trait `From<aya::programs::ProgramError>` is not implemented for `anyhow::Error`, which is required by `Result<(), _>: FromResidual<Result<Infallible, aya::programs::ProgramError>>`
   |
   = note: the question mark operation (`?`) implicitly performs a conversion on the error value using the `From` trait
   = help: the following other types implement trait `FromResidual<R>`:
             <Result<T, F> as FromResidual<Result<Infallible, E>>>
             <Result<T, F> as FromResidual<Yeet<E>>>
   = note: required for `Result<(), anyhow::Error>` to implement `FromResidual<Result<Infallible, aya::programs::ProgramError>>`

error[E0277]: `?` couldn't convert the error to `anyhow::Error`
  --> test-buildscript-hotness/src/main.rs:52:27
   |
52 |     signal::ctrl_c().await?;
   |                           ^ the trait `From<std::io::Error>` is not implemented for `anyhow::Error`, which is required by `Result<(), _>: FromResidual<Result<Infallible, std::io::Error>>`
   |
   = note: the question mark operation (`?`) implicitly performs a conversion on the error value using the `From` trait
   = help: the following other types implement trait `FromResidual<R>`:
             <Result<T, F> as FromResidual<Result<Infallible, E>>>
             <Result<T, F> as FromResidual<Yeet<E>>>
   = note: required for `Result<(), anyhow::Error>` to implement `FromResidual<Result<Infallible, std::io::Error>>`

warning: unused import: `anyhow::Context`
 --> test-buildscript-hotness/src/main.rs:1:5
  |
1 | use anyhow::Context as _;
  |     ^^^^^^^^^^^^^^^
  |
  = note: `#[warn(unused_imports)]` on by default

Some errors have detailed explanations: E0277, E0599.
For more information about an error, try `rustc --explain E0277`.
warning: `test-buildscript-hotness` (bin "test-buildscript-hotness") generated 1 warning
error: could not compile `test-buildscript-hotness` (bin "test-buildscript-hotness") due to 5 previous errors; 1 warning emitted

This might be something unique to my environment, but I'd like to be sure before we merge it.
You should be able to reproduce with:

cargo generate -g https://github.com/aya-rs/aya-template -b build-script-hotness

[dave-tucker]

👀 what does rustfmt do here that warrants skipping?

[tamird]

It tries to reorder the imports in the sk_msg case because use {{crate_name}}_common::SockKey;( use test_common::SockKey;`) sorts after these items.

[tamird]

This might be something unique to my environment, but I'd like to be sure before we merge it. You should be able to reproduce with:

cargo generate -g https://github.com/aya-rs/aya-template -b build-script-hotness

is that the invocation you used? Doesn't that pull this repo at HEAD rather than this PR?

[tamird]

Ah, I think you are running into this caveat because we're now building anyhow with no_std and you must be using Rust < 1.81.

[tamird]

Should work for you now

[vadorovsky]

Works for me 🐧