Add rust-toolchain.toml

Add a `rust-toolchain.toml` file that specifies the channel and
components needed to build uefi-rs. See
https://rust-lang.github.io/rustup/overrides.html#the-toolchain-file for
documentation of the `rust-toolchain.toml` format.

Remove the `--toolchain` option from `xtask`, as using this file is a
simpler alternative. Also remove the instructions for installing the
nightly toolchain from the readme, as `rustup` will do this
automatically now.

The template application has been updated to add a
`rust-toolchain.toml`, and `BUILDING.md` has been updated to mention it
as well.

The `toolchain` action previously used in the CI is unmaintained and
doesn't understand `rust-toolchain.toml` (it does understand the older
`rust-toolchain` file, but that doesn't allow for including required
components). Since the runners come with rustup already installed, we
don't actually need a complex action here anyway, so just remove those
sections entirely. A few jobs need extra components installed, do that
with `rustup component add`.

Note that this change will also cause `xtask` itself to be built with
nightly. That should generally be fine, we only had it using stable
because of #397, and in the
future we can easily temporarily pin to a non-current nightly if a bug
occurs with an `xtask` dependency again.

Fixes #498

Author: nicholasbishop

.github/workflows/rust.yml

@@ -28,18 +28,6 @@ jobs:
         sudo apt-get update
         sudo apt-get install qemu-system-arm qemu-efi-aarch64 -y
 
-    - name: Install stable
-      uses: actions-rs/toolchain@v1
-      with:
-          toolchain: stable
-
-    - name: Install latest nightly
-      uses: actions-rs/toolchain@v1
-      with:
-          toolchain: nightly
-          components: rust-src
-      # TODO: cache Rust binaries
-
     - name: Build
       run: cargo xtask build --target aarch64
 
@@ -59,18 +47,6 @@ jobs:
         sudo apt-get update
         sudo apt-get install qemu-system-x86 ovmf -y
 
-    - name: Install stable
-      uses: actions-rs/toolchain@v1
-      with:
-          toolchain: stable
-
-    - name: Install latest nightly
-      uses: actions-rs/toolchain@v1
-      with:
-          toolchain: nightly
-          components: rust-src
-      # TODO: cache Rust binaries
-
     - name: Build
       run: cargo xtask build --target x86_64
 
@@ -106,18 +82,6 @@ jobs:
         curl -o OVMF32_CODE.fd https://raw.githubusercontent.com/retrage/edk2-nightly/${EDK2_NIGHTLY_COMMIT}/bin/RELEASEIa32_OVMF_CODE.fd
         curl -o OVMF32_VARS.fd https://raw.githubusercontent.com/retrage/edk2-nightly/${EDK2_NIGHTLY_COMMIT}/bin/RELEASEIa32_OVMF_VARS.fd
 
-    - name: Install stable
-      uses: actions-rs/toolchain@v1
-      with:
-          toolchain: stable
-
-    - name: Install latest nightly
-      uses: actions-rs/toolchain@v1
-      with:
-          toolchain: nightly
-          components: rust-src
-      # TODO: cache Rust binaries
-
     - name: Build
       run: cargo xtask build --target ia32
 
@@ -132,18 +96,6 @@ jobs:
       - name: Checkout sources
         uses: actions/checkout@v2
 
-      - name: Install stable
-        uses: actions-rs/toolchain@v1
-        with:
-            toolchain: stable
-
-      - name: Install latest nightly
-        uses: actions-rs/toolchain@v1
-        with:
-            profile: minimal
-            toolchain: nightly
-            components: rust-src
-
       - name: Run cargo test
         run: cargo xtask test
 
@@ -154,26 +106,15 @@ jobs:
       - name: Checkout sources
         uses: actions/checkout@v2
 
-      - name: Install stable
-        uses: actions-rs/toolchain@v1
-        with:
-            toolchain: stable
-
-      - name: Install latest nightly
-        uses: actions-rs/toolchain@v1
-        with:
-            profile: minimal
-            toolchain: nightly
-            components: rustfmt, clippy, rust-src
-
       - name: Run cargo fmt
-        uses: actions-rs/cargo@v1
-        with:
-          command: fmt
-          args: --all -- --check
+        run: |
+          rustup component add rustfmt
+          cargo fmt --all -- --check
 
       - name: Run clippy
-        run: cargo xtask clippy --warnings-as-errors
+        run: |
+          rustup component add clippy
+          cargo xtask clippy --warnings-as-errors
 
       - name: Run cargo doc
         run: cargo xtask doc --warnings-as-errors
@@ -185,20 +126,10 @@ jobs:
       - name: Checkout sources
         uses: actions/checkout@v2
 
-      - name: Install stable
-        uses: actions-rs/toolchain@v1
-        with:
-            toolchain: stable
-
-      - name: Install latest nightly toolchain that includes Miri
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: nightly
-          components: miri
-
       - name: Run miri
-        run: cargo xtask miri
+        run: |
+          rustup component add miri
+          cargo xtask miri
 
   # This job tests that the template app builds successfully with the
   # released versions of the libraries on crates.io.
@@ -214,17 +145,6 @@ jobs:
     - name: Checkout sources
       uses: actions/checkout@v2
 
-    - name: Install stable
-      uses: actions-rs/toolchain@v1
-      with:
-          toolchain: stable
-
-    - name: Install latest nightly
-      uses: actions-rs/toolchain@v1
-      with:
-          toolchain: nightly
-          components: rust-src
-
     - name: Build
       run: cargo xtask test-latest-release
 
@@ -235,17 +155,5 @@ jobs:
       - name: Checkout sources
         uses: actions/checkout@v2
 
-      - name: Install stable
-        uses: actions-rs/toolchain@v1
-        with:
-            toolchain: stable
-
-      - name: Install latest nightly
-        uses: actions-rs/toolchain@v1
-        with:
-            profile: minimal
-            toolchain: nightly
-            components: rust-src
-
       - name: Build
         run: cargo xtask build

BUILDING.md

@@ -13,25 +13,31 @@ targets.
 [`i686-unknown-uefi`]: https://github.com/rust-lang/rust/blob/HEAD/compiler/rustc_target/src/spec/i686_unknown_uefi.rs
 [`x86_64-unknown-uefi`]: https://github.com/rust-lang/rust/blob/HEAD/compiler/rustc_target/src/spec/x86_64_unknown_uefi.rs
 
-## Building
+## Building for a UEFI target
 
-- Install a `nightly` version of the Rust [toolchain](https://rust-lang.github.io/rustup/concepts/toolchains.html):
+For instructions on building the `uefi-rs` crates, see the
+[README](README.md). This section is for building your own crates,
+outside of the `uefi-rs` repo.
 
-  `rustup toolchain install nightly`
+- Install a `nightly` version of the Rust [toolchain] and include the
+  `rust-src` [component]. The easiest way to do this is with a
+  `rust-toolchain.toml` file, for example:
+  
+  ```toml
+  [toolchain]
+  channel = "nightly"
+  components = ["rust-src"]
+  ```
 
-  It is not currently possible to build the core crate with a stable version of the Rust compiler.
+- Build the crate:
 
-- You need to add the `rust-src` toolchain [component](https://rust-lang.github.io/rustup/concepts/components.html)
-  (if it's not already installed), which Cargo will use to build the core crates for the UEFI target:
-
-  `rustup component add --toolchain nightly rust-src`
-
-- Build this crate using the `nightly` toolchain:
-
-  `cargo +nightly build --target x86_64-unknown-uefi`.
+  `cargo build --target x86_64-unknown-uefi`.
 
 - The `target` directory will contain a `x86_64-unknown-uefi` subdirectory,
   where you will find a `<crate name>.efi` file - a normal UEFI executable.
+  
+[toolchain]: https://rust-lang.github.io/rustup/concepts/toolchains.html
+[component]: https://rust-lang.github.io/rustup/concepts/components.html
 
 ## Running
 

README.md

@@ -63,12 +63,6 @@ the [UEFI specification][spec] for detailed information.
 
 ## Building and testing uefi-rs
 
-Install the `nightly` version of Rust and the `rust-src` component:
-```
-rustup toolchain install nightly
-rustup component add --toolchain nightly rust-src
-```
-
 Use the `cargo xtask` command to build and test the crate.
 
 Available commands:

rust-toolchain.toml

@@ -0,0 +1,7 @@
+[toolchain]
+# Nightly is required due to use of unstable features.
+channel = "nightly"
+components = [
+    # Needed for `-Zbuild-std`.
+    "rust-src",
+]

template/README.md

@@ -8,7 +8,8 @@ how to build and run a UEFI application developed using `uefi-rs`.
 
 ## File structure
 
-- [`.cargo/config`](./.cargo/config) file sets some `build-std` options.
+- [`.cargo/config`](./.cargo/config) sets some `build-std` options.
+- [`rust-toolchain.toml`](rust-toolchain.toml) sets the nightly channel.
 - [`Cargo.toml`](./Cargo.toml) shows the necessary dependencies.
 - [`src/main.rs`](./src/main.rs) has a minimal entry point that
   initializes the `uefi-services` crate and exits successfully.

template/rust-toolchain.toml

@@ -0,0 +1,3 @@
+[toolchain]
+channel = "nightly"
+components = ["rust-src"]

xtask/src/cargo.rs

@@ -118,7 +118,6 @@ pub fn fix_nested_cargo_env(cmd: &mut Command) {
 pub struct Cargo {
     pub action: CargoAction,
     pub features: Vec<Feature>,
-    pub toolchain: Option<String>,
     pub packages: Vec<Package>,
     pub release: bool,
     pub target: Option<UefiArch>,
@@ -131,10 +130,6 @@ impl Cargo {
 
         fix_nested_cargo_env(&mut cmd);
 
-        if let Some(toolchain) = &self.toolchain {
-            cmd.arg(&format!("+{}", toolchain));
-        }
-
         let action;
         let mut sub_action = None;
         let mut extra_args: Vec<&str> = Vec::new();
@@ -239,15 +234,14 @@ mod tests {
         let cargo = Cargo {
             action: CargoAction::Doc { open: true },
             features: vec![Feature::Alloc],
-            toolchain: Some("nightly".into()),
             packages: vec![Package::Uefi, Package::Xtask],
             release: false,
             target: None,
             warnings_as_errors: true,
         };
         assert_eq!(
             command_to_string(&cargo.command().unwrap()),
-            "RUSTDOCFLAGS=-Dwarnings cargo +nightly doc --package uefi --package xtask --features alloc --open"
+            "RUSTDOCFLAGS=-Dwarnings cargo doc --package uefi --package xtask --features alloc --open"
         );
     }
 }

xtask/src/main.rs

@@ -11,18 +11,15 @@ mod util;
 use anyhow::Result;
 use cargo::{fix_nested_cargo_env, Cargo, CargoAction, Feature, Package};
 use clap::Parser;
-use opt::{Action, BuildOpt, ClippyOpt, DocOpt, MiriOpt, Opt, QemuOpt};
+use opt::{Action, BuildOpt, ClippyOpt, DocOpt, Opt, QemuOpt};
 use std::process::Command;
 use tempfile::TempDir;
 use util::{command_to_string, run_cmd};
 
-const NIGHTLY: &str = "nightly";
-
 fn build(opt: &BuildOpt) -> Result<()> {
     let cargo = Cargo {
         action: CargoAction::Build,
         features: Feature::more_code(),
-        toolchain: opt.toolchain.or(NIGHTLY),
         packages: Package::all_except_xtask(),
         release: opt.build_mode.release,
         target: Some(*opt.target),
@@ -36,7 +33,6 @@ fn clippy(opt: &ClippyOpt) -> Result<()> {
     let cargo = Cargo {
         action: CargoAction::Clippy,
         features: Feature::more_code(),
-        toolchain: opt.toolchain.or(NIGHTLY),
         packages: Package::all_except_xtask(),
         release: false,
         target: Some(*opt.target),
@@ -48,7 +44,6 @@ fn clippy(opt: &ClippyOpt) -> Result<()> {
     let cargo = Cargo {
         action: CargoAction::Clippy,
         features: Vec::new(),
-        toolchain: None,
         packages: vec![Package::Xtask],
         release: false,
         target: None,
@@ -62,7 +57,6 @@ fn doc(opt: &DocOpt) -> Result<()> {
     let cargo = Cargo {
         action: CargoAction::Doc { open: opt.open },
         features: Feature::more_code(),
-        toolchain: opt.toolchain.or(NIGHTLY),
         packages: Package::published(),
         release: false,
         target: None,
@@ -72,11 +66,10 @@ fn doc(opt: &DocOpt) -> Result<()> {
 }
 
 /// Run unit tests and doctests under Miri.
-fn run_miri(opt: &MiriOpt) -> Result<()> {
+fn run_miri() -> Result<()> {
     let cargo = Cargo {
         action: CargoAction::Miri,
         features: [Feature::Exts].into(),
-        toolchain: opt.toolchain.or(NIGHTLY),
         packages: [Package::Uefi].into(),
         release: false,
         target: None,
@@ -100,7 +93,6 @@ fn run_vm_tests(opt: &QemuOpt) -> Result<()> {
     let cargo = Cargo {
         action: CargoAction::Build,
         features,
-        toolchain: opt.toolchain.or(NIGHTLY),
         packages: vec![Package::UefiTestRunner],
         release: opt.build_mode.release,
         target: Some(*opt.target),
@@ -119,7 +111,6 @@ fn run_host_tests() -> Result<()> {
     let cargo = Cargo {
         action: CargoAction::Test,
         features: Vec::new(),
-        toolchain: None,
         packages: vec![Package::Xtask],
         release: false,
         target: None,
@@ -131,7 +122,6 @@ fn run_host_tests() -> Result<()> {
     let cargo = Cargo {
         action: CargoAction::Test,
         features: vec![Feature::Exts],
-        toolchain: Some(NIGHTLY.into()),
         // Don't test uefi-services (or the packages that depend on it)
         // as it has lang items that conflict with `std`.
         packages: vec![Package::Uefi, Package::UefiMacros],
@@ -173,7 +163,7 @@ fn test_latest_release() -> Result<()> {
     let mut build_cmd = Command::new("cargo");
     fix_nested_cargo_env(&mut build_cmd);
     build_cmd
-        .args(&["+nightly", "build", "--target", "x86_64-unknown-uefi"])
+        .args(&["build", "--target", "x86_64-unknown-uefi"])
         .current_dir(tmp_dir.join("template"));
 
     // Check that the command is indeed in BUILDING.md, then verify the
@@ -190,7 +180,7 @@ fn main() -> Result<()> {
         Action::Build(build_opt) => build(build_opt),
         Action::Clippy(clippy_opt) => clippy(clippy_opt),
         Action::Doc(doc_opt) => doc(doc_opt),
-        Action::Miri(miri_opt) => run_miri(miri_opt),
+        Action::Miri(_) => run_miri(),
         Action::Run(qemu_opt) => run_vm_tests(qemu_opt),
         Action::Test(_) => run_host_tests(),
         Action::TestLatestRelease(_) => test_latest_release(),