ci: switch code coverage to grcov

.github/workflows/check.yaml

@@ -256,9 +256,10 @@ jobs:
         id: toolchain
         uses: actions-rs/toolchain@v1
         with:
-          toolchain: stable
+          toolchain: nightly
           target: x86_64-unknown-linux-musl
           override: true
+          components: llvm-tools-preview
 
       - name: Setup Cargo cache
         uses: actions/cache@v2.1.6
@@ -279,14 +280,34 @@ jobs:
             ${{ runner.os }}-cargo-coverage-${{ steps.toolchain.outputs.rustc_hash }}-
             ${{ runner.os }}-cargo-coverage-
 
-      - name: Run cargo tarpaulin
-        uses: actions-rs/tarpaulin@v0.1
+      - name: Download grcov
+        run: |
+          mkdir -p "${HOME}/.local/bin"
+          curl -sL https://github.com/mozilla/grcov/releases/latest/download/grcov-linux-x86_64.tar.bz2 | tar -jxf - -C "${HOME}/.local/bin"
+          echo "$HOME/.local/bin" >> $GITHUB_PATH
+
+
+      - name: Run test suite with profiling enabled
+        uses: actions-rs/cargo@v1
         with:
-          version: '0.18.2'
-          args: '--avoid-cfg-tarpaulin'
+          command: test
+          args: --all-features --no-fail-fast
+        env:
+           CARGO_INCREMENTAL: '0'
+           RUSTFLAGS: '-Zinstrument-coverage'
+           RUSTDOCFLAGS: "-Cpanic=abort -Zinstrument-coverage -Zunstable-options --persist-doctests ${{ github.workspace }}/target/debug/doctestbins"
+           LLVM_PROFILE_FILE: "cargo-test-%p-%m.profraw"
+
+      - name: Build grcov report
+        run: |
+          mkdir -p target/coverage
+          grcov . --binary-path ./target/debug/deps/ -s . -t lcov --branch --ignore-not-existing --ignore '../*' --ignore "/*" -o target/coverage/tests.lcov
+          grcov . --binary-path ./target/debug/doctestbins/ -s . -t lcov --branch --ignore-not-existing --ignore '../*' --ignore "/*" -o target/coverage/doctests.lcov
 
       - name: Upload to codecov.io
         uses: codecov/codecov-action@v2
+        with:
+          files: target/coverage/*.lcov
 
 
   build-image: