refactor(ci): improve rustfmt perf and cleanup

- Install nightly through moonrepo, so it'll be cached.
- Always run rustfmt on --all for both push/pull.
It doesn't compile anything and runs on `--all` in a few seconds.

Benchmark: seems to reduce time from ~15 seconds to ~5 seconds, and
logs indeed show that nothing is installed, only rustfmt is run.

Unrelated: remove clippy/rustfmt from the components in
rust-toolchain.toml, when using the `default` profile they are already
included.

.github/actions/install_rust/action.yml

@@ -9,5 +9,6 @@ runs:
         cache-base: main(-v[0-9].*)?
         inherit-toolchain: true
         bins: taplo-cli@0.9.0, cargo-machete
+        channel: nightly-2024-04-29 # Just install for rustfmt, rust-toolchain.toml overrides it.
       env:
         RUSTFLAGS: "-C link-arg=-fuse-ld=lld"

.github/workflows/main.yml

@@ -62,9 +62,6 @@ jobs:
           git diff --exit-code Cargo.lock
 
       # Run code style on PR.
-      - name: "Run rustfmt pull request"
-        if: github.event_name == 'pull_request'
-        run: ci/bin/python scripts/run_tests.py --command rustfmt --changes_only --commit_id ${{ github.event.pull_request.base.sha }}
       - name: "Run clippy pull request"
         if: github.event_name == 'pull_request'
         run: ci/bin/python scripts/run_tests.py --command clippy --changes_only --commit_id ${{ github.event.pull_request.base.sha }}
@@ -73,9 +70,11 @@ jobs:
         run: ci/bin/python scripts/run_tests.py --command doc --changes_only --commit_id ${{ github.event.pull_request.base.sha }}
 
       # Run code style on push.
-      - name: "Run rustfmt on push"
-        if: github.event_name == 'push'
-        run: ci/bin/python scripts/run_tests.py --command rustfmt
+      - name: "Run rustfmt"
+        # The nightly here is coupled with the one in install_rust/action.yml.
+        # If we move the install here we can use a const.
+        run: cargo +nightly-2024-04-29 fmt --all -- --check
+
       - name: "Run clippy on push"
         if: github.event_name == 'push'
         run: ci/bin/python scripts/run_tests.py --command clippy

rust-toolchain.toml

@@ -1,5 +1,5 @@
 [toolchain]
 channel = "1.83"
-components = ["clippy", "rustc-dev", "rustfmt"]
+components = ["rustc-dev"]
 profile = "default"
 targets = ["x86_64-unknown-linux-gnu"]

scripts/run_tests.py

@@ -19,7 +19,6 @@
 class BaseCommand(Enum):
     TEST = "test"
     CODECOV = "codecov"
-    RUSTFMT = "rustfmt"
     CLIPPY = "clippy"
     DOC = "doc"
 
@@ -39,9 +38,6 @@ def cmd(self, crates: Set[str]) -> List[str]:
                 "--output-path",
                 "codecov.json",
             ] + package_args
-        elif self == BaseCommand.RUSTFMT:
-            fmt_args = package_args if len(package_args) > 0 else ["--all"]
-            return ["scripts/rust_fmt.sh"] + fmt_args + ["--", "--check"]
         elif self == BaseCommand.CLIPPY:
             clippy_args = package_args if len(package_args) > 0 else ["--workspace"]
             return ["cargo", "clippy"] + clippy_args