ci: update codecov with nix

Author: yanganto

.github/workflows/codecov.yml

@@ -14,38 +14,22 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - name: Set up toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: stable
-          override: true
-          components: rustfmt, llvm-tools-preview
+      - name: Install Nix
+        uses: cachix/install-nix-action@v26
       - name: Build
-        uses: actions-rs/cargo@v1
-        with:
-          command: build
-          args: --release
-        env:
-          CARGO_INCREMENTAL: "0"
-          RUSTFLAGS: "-Cinstrument-coverage"
-          RUSTDOCFLAGS: "-Cinstrument-coverage"
+        run: nix develop .#codecov -c cargo build --release
       - name: Test
-        uses: actions-rs/cargo@v1
-        with:
-          command: test
-          args: --all-features --no-fail-fast
-        env:
-          CARGO_INCREMENTAL: "0"
-          RUSTFLAGS: "-Cinstrument-coverage"
-          RUSTDOCFLAGS: "-Cinstrument-coverage"
+        run: nix develop .#codecov -c cargo test --all-features --no-fail-fast --tests
       - name: Install grcov
-        run: if [[ ! -e ~/.cargo/bin/grcov ]]; then cargo install grcov; fi
+        run: nix develop .#codecov -c cargo install grcov
       - name: Generate coverage
-        run: grcov . --binary-path target/debug/deps/ -s . -t lcov --branch --ignore-not-existing --ignore '../**' --ignore '/*' -o coverage.lcov
+        run: nix develop .#codecov -c grcov . --binary-path target/debug/deps/ -s . -t lcov --branch --ignore-not-existing --ignore '../**' --ignore '/*' -o coverage.lcov
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v3
+        uses: codecov/codecov-action@v4
         with:
           files: ./coverage.lcov
           flags: rust
-          fail_ci_if_error: true
+          # TODO: set true when CODECOV_TOKEN is set
+          fail_ci_if_error: false
+        env:
+          CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}

flake.nix

@@ -23,6 +23,11 @@
             pkg-config
         ];
         cargoToml = builtins.fromTOML (builtins.readFile ./Cargo.toml);
+
+        stableWithLlvm = pkgs.rust-bin.nightly.latest.default.override {
+          extensions = [ "rustfmt" "llvm-tools-preview" ];
+          targets = [ ];
+        };
       in
       with pkgs;
       {
@@ -52,6 +57,15 @@
               rust-bin.nightly.latest.default
             ];
           };
+
+          codecov = mkShell {
+            buildInputs = commonPackages ++ [
+              stableWithLlvm
+            ];
+            CARGO_INCREMENTAL = "0";
+            RUSTFLAGS = "-Cinstrument-coverage";
+            RUSTDOCFLAGS = "-Cinstrument-coverage";
+          };
         };
       }
     );