Can we skip rustfmt because it is not available in beta channel for Raspberry Pi ARMv7 about tonic

[rlabrecque]

Hey @kevingzhang, rustfmt can be disabled with a feature flag on tonic-build. You can turn it off like so:

[build-dependencies]
tonic-build = { git = "https://github.com/hyperium/tonic", default-features = false, features = ["transport"] }

Replae git = "", with version = "" if you're using a release from crates.io!

[kevingzhang]

BTW, Tower-gRPC compile and works fine. since it doesn't require rustfmt.
so the worst case I can use Tower-gRPC instead going all the way back to Hyper. :)

[kevingzhang]

thanks, it works !!

[LucioFranco]

Yeah, the one issue with not rustfmting the code is that you get super super super nasty errors since it puts all the code into one line and the compiler cant figure out how to show it.

[xmclark]

Alternatively, can tonic import rustfmt as a library and do the text processing at string-build-time instead of calling the external cli tool? Maybe that has tradeoffs, but at least then consumers of this library who do not want or cannot install rustfmt can get nice error messages.

[LucioFranco]

@xmclark last I checked that was not possible, or I couldn't figure it out. If someone could figure that out that would be amazing!

[davidgraeff]

I have done that in another crate of mine.

https://github.com/davidgraeff/braintree-payment-graphql-rs/blob/master/braintree-queries-generator/src/generate.rs#L10

#[cfg(feature = "rustfmt")]
fn format(input_rust_code: String) -> Option<String> {
    use rustfmt_nightly::{Config, Input, Session};

    let mut config = Config::default();

    config.set().emit_mode(rustfmt_nightly::EmitMode::Stdout);
    config.set().verbose(rustfmt_nightly::Verbosity::Quiet);

    let mut out = Vec::with_capacity(input_rust_code.len() * 2);

    let r = Session::new(config, Some(&mut out)).format(Input::Text(input_rust_code));
    match r {
        Err(e) => {
            format_err!("rustfmt error: {:?}", e);
            None
        }
        _ => match out.len() {
            0 => None,
            // Unwrap should be safe here, rustfmt generates utf8 only
            _ => Some(String::from_utf8(out).unwrap()),
        },
    }
}

[LucioFranco]

@davidgraeff can this code run on stable?

[davidgraeff]

To be honest, I don't know. Because of the current async situation in the rust ecosystem I'm on rust nightly. I haven't found a toolchain file in their repo, so I assume it works on stable, but also haven't checked their dependencies.

[LucioFranco]

Yeah, unfortunately, this depends on unstable nightly features :(

error[E0554]: `#![feature]` may not be used on the stable release channel
   --> /Users/lucio/.cargo/registry/src/github.com-1ecc6299db9ec823/rustc-ap-graphviz-606.0.0/lib.rs:277:1
    |
277 | #![feature(rustc_private, nll)]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0554]: `#![feature]` may not be used on the stable release channel
  --> /Users/lucio/.cargo/registry/src/github.com-1ecc6299db9ec823/smallvec-0.6.10/lib.rs:33:32
   |
33 | #![cfg_attr(feature = "union", feature(untagged_unions))]
   |                                ^^^^^^^^^^^^^^^^^^^^^^^^

error[E0554]: `#![feature]` may not be used on the stable release channel
  --> /Users/lucio/.cargo/registry/src/github.com-1ecc6299db9ec823/smallvec-0.6.10/lib.rs:35:37
   |
35 | #![cfg_attr(feature = "may_dangle", feature(dropck_eyepatch))]
   |                                     ^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to previous error

[sprhawk]

I encounter a same situation.
I'm using yocto with meta-rust-bin to build rust application. a rustfmt doesn't exist in meta-rust-bin.
Although I can disable rustfmt feature for yocto build, but it will also disabled in normal development environment.

I think there is no way to set to use "rustfmt" in development environment, and no "rustfmt" when build for yocto ( build script is built for HOST same like the development environment )

[LucioFranco]

I am not familiar with yocto but is it possible to pass a feature flag to the create that contains tonic build? that way you can do something like:

[features]
fmt = ["tonic-build/rustfmt"]

then you can build it with

cargo build --features fmt

[sprhawk]

I am not familiar with yocto but is it possible to pass a feature flag to the create that contains tonic build? that way you can do something like:

[features]
fmt = ["tonic-build/rustfmt"]

then you can build it with

cargo build --features fmt

I mean meta-rust-bin doesn't include a rustfmt, so I had to disable fmt feature, not enable it.

[hechaoli]

I am not familiar with yocto but is it possible to pass a feature flag to the create that contains tonic build? that way you can do something like:

[features]
fmt = ["tonic-build/rustfmt"]

then you can build it with

cargo build --features fmt

I mean meta-rust-bin doesn't include a rustfmt, so I had to disable fmt feature, not enable it.

I encountered the same issue with yocto. However, I'm using meta-rust which should have rustfmt. Yet somehow it complains about rustfmt missing. I couldn't figure out a way to configure yocto to work. Eventually, I found that it works if you just disable format using configure. That is, change build.rs to the following instead of using tonic_build::compile_protos("proto/helloworld.proto")?; like in the example.

fn main() -> Result<(), Box<dyn std::error::Error>> {
   tonic_build::configure()
        .format(false)
        .compile(
            &["proto/helloworld.proto"],
            &["proto/"],
        )?;
   Ok(())
}

The side-effect is of course all generated code in one line.