CI: Switch tooling setup to Nix

.forgejo/workflows/verify.yaml

@@ -17,46 +17,53 @@ jobs:
     timeout-minutes: 20
     container:
       image: rust:slim
+      env:
+        RUSTUP_HOME: /rust/rustup
+        CARGO_HOME: /rust/cargo
     steps:
       - name: Install action dependencies
-        run: apt-get install --no-install-recommends --update -y nodejs curl git
+        run: >
+          apt-get install --no-install-recommends --update -y
+          nodejs git nix
 
       - name: Checkout code
         uses: actions/checkout@v6
         with:
           fetch-tags: true
 
+      - name: Set up Nix
+        run: |
+          {
+            echo experimental-features = nix-command flakes
+          } >> /etc/nix/nix.conf
+
       - name: Set up Rust toolchain
         run: |
-          rustup component add llvm-tools
-          rustup component add --toolchain nightly rustfmt clippy
-          rustup target add x86_64-unknown-linux-gnu
-          rustup target add x86_64-unknown-linux-musl
+          mkdir -p "$RUSTUP_HOME"
+          mkdir -p "$CARGO_HOME"
 
-      - name: Set up additional tooling
-        run: .forgejo/workflows/setup-tools.sh
+          rust_version=$(
+              grep '^rust-version = "' Cargo.toml \
+              | cut -d '"' -f 2
+          )
+
+          # rustup default "$rust_version"
+          # rustup toolchain install nightly
+          # rustup component add llvm-tools
+          # rustup component add --toolchain nightly rustfmt clippy
+          # rustup target add x86_64-unknown-linux-musl x86_64-unknown-linux-gnu
 
       - name: Set up CI user
         run: |
-          useradd -m ci && chown -R ci:ci .
-          git config --global --add safe.directory "$PWD"
+          chown -R ci:ci "$RUSTUP_HOME"
+          chown -R ci:ci "$CARGO_HOME"
+          chown -R ci:ci "$PWD"
+          printf '[safe]\ndirectory = %s\n' "$PWD" > /etc/gitconfig
 
-      - name: Text matches
-        run: just ci todos-assess version-assess spell
-      - name: Schema lint
-        run: just ci schema-lint
-      - name: Deny
-        run: just ci deny
-      - name: Format
-        run: just ci format-assess
-      - name: Lint
-        run: just ci lint-assess
-      - name: MSRV
-        run: just ci msrv-assess
-      - name: Cargo check
-        run: just ci check
-      - name: Test
-        run: just ci test
-      - name: Coverage
-        run: just ci cover-assess
+      - name: Set up Nix
+        run: mkdir /nix && chown alice /nix
 
+      - name: Set up Nix development shell
+        run: su ci -c "nix develop --command just smoke"
+      - name: Assess
+        run: su ci -c "nix develop --command just verify"