Unconditionally install rustfmt

Rustfmt used to be optional for nightlies long ago, but it is now
always present. Also rename rust-toolchain to rust-toolchain.toml.

Author: bjorn3

.github/workflows/main.yml

@@ -28,7 +28,7 @@ jobs:
 
     - name: Avoid installing rustc-dev
       run: |
-        sed -i 's/components.*/components = ["rustfmt"]/' rust-toolchain
+        sed -i 's/components.*/components = ["rustfmt"]/' rust-toolchain.toml
         rustfmt -v
 
     - name: Rustfmt
@@ -88,7 +88,7 @@ jobs:
       uses: actions/cache@v4
       with:
         path: build/cg_clif
-        key: ${{ runner.os }}-${{ matrix.env.TARGET_TRIPLE }}-cargo-build-target-${{ hashFiles('rust-toolchain', '**/Cargo.lock') }}
+        key: ${{ runner.os }}-${{ matrix.env.TARGET_TRIPLE }}-cargo-build-target-${{ hashFiles('rust-toolchain.toml', '**/Cargo.lock') }}
 
     - name: Set MinGW as the default toolchain
       if: matrix.os == 'windows-latest' && matrix.env.TARGET_TRIPLE == 'x86_64-pc-windows-gnu'
@@ -158,7 +158,7 @@ jobs:
       uses: actions/cache@v4
       with:
         path: build/cg_clif
-        key: ${{ runner.os }}-x86_64-unknown-linux-gnu-cargo-build-target-${{ hashFiles('rust-toolchain', '**/Cargo.lock') }}
+        key: ${{ runner.os }}-x86_64-unknown-linux-gnu-cargo-build-target-${{ hashFiles('rust-toolchain.toml', '**/Cargo.lock') }}
 
     - name: Install hyperfine
       run: |
@@ -207,7 +207,7 @@ jobs:
       uses: actions/cache@v4
       with:
         path: build/cg_clif
-        key: ${{ runner.os }}-${{ matrix.env.TARGET_TRIPLE }}-dist-cargo-build-target-${{ hashFiles('rust-toolchain', '**/Cargo.lock') }}
+        key: ${{ runner.os }}-${{ matrix.env.TARGET_TRIPLE }}-dist-cargo-build-target-${{ hashFiles('rust-toolchain.toml', '**/Cargo.lock') }}
 
     - name: Set MinGW as the default toolchain
       if: matrix.os == 'windows-latest' && matrix.env.TARGET_TRIPLE == 'x86_64-pc-windows-gnu'

.github/workflows/rustc.yml

@@ -20,7 +20,7 @@ jobs:
       uses: actions/cache@v4
       with:
         path: build/cg_clif
-        key: ${{ runner.os }}-rustc-test-cargo-build-target-${{ hashFiles('rust-toolchain', 'Cargo.lock') }}
+        key: ${{ runner.os }}-rustc-test-cargo-build-target-${{ hashFiles('rust-toolchain.toml', 'Cargo.lock') }}
 
     - name: Test
       run: ./scripts/test_bootstrap.sh
@@ -40,7 +40,7 @@ jobs:
       uses: actions/cache@v4
       with:
         path: build/cg_clif
-        key: ${{ runner.os }}-rustc-test-cargo-build-target-${{ hashFiles('rust-toolchain', 'Cargo.lock') }}
+        key: ${{ runner.os }}-rustc-test-cargo-build-target-${{ hashFiles('rust-toolchain.toml', 'Cargo.lock') }}
 
     - name: Install ripgrep
       run: |

rust-toolchain

@@ -0,0 +1,4 @@
+[toolchain]
+channel = "nightly-2025-12-16"
+components = ["rust-src", "rustc-dev", "llvm-tools", "rustfmt"]
+profile = "minimal"

rust-toolchain.toml

@@ -22,8 +22,7 @@ case $1 in
     "prepare")
         echo "=> Installing new nightly"
         rustup toolchain install --profile minimal "nightly-${TOOLCHAIN}" # Sanity check to see if the nightly exists
-        sed -i "s/\"nightly-.*\"/\"nightly-${TOOLCHAIN}\"/" rust-toolchain
-        rustup component add rustfmt || true
+        sed -i "s/\"nightly-.*\"/\"nightly-${TOOLCHAIN}\"/" rust-toolchain.toml
 
         echo "=> Uninstalling all old nightlies"
         for nightly in $(rustup toolchain list | grep nightly | grep -v "$TOOLCHAIN" | grep -v nightly-x86_64); do
@@ -35,7 +34,7 @@ case $1 in
         ./y.sh prepare
         ;;
     "commit")
-        git add rust-toolchain
+        git add rust-toolchain.toml
         git commit -m "Rustup to $(rustc -V)"
         ;;
     "push")