#2461: Use cache mount for code coverage

Author: JacobDomagala

.github/workflows/build-docker-images.yml

@@ -82,3 +82,25 @@ jobs:
             *.args.CACHE_ID=${{ matrix.target }}
         env:
           GIT_BRANCH: ${{ github.head_ref || github.ref_name }}
+
+      - name: Retrieve build artifacts
+        if: ${{ matrix.target == 'vt-build-amd64-ubuntu-22-04-gcc-11-cpp' }}
+        run: |
+          # We rely on the persistence of data on cache mounts with identical IDs and builders.
+          # This allows us to copy build artifacts from the "bake" step and use the Codecov action within the GitHub environment.
+
+          echo "
+          FROM ubuntu:latest
+          RUN --mount=type=cache,id=BUILD-${{ matrix.target }},target=/build/vt \
+          mkdir -p /vt \
+          && cp -p -R /build/vt/. /vt/ || true
+          " >> tmp_dockerfile
+
+          docker buildx build --builder ${{ steps.setup-buildx.outputs.name }} -f tmp_dockerfile --output type=local,dest=build .
+
+      - name: Upload coverage
+        if: ${{ matrix.target == 'vt-build-amd64-ubuntu-22-04-gcc-11-cpp' }}
+        uses: codecov/codecov-action@v5
+        with:
+          files: build/vt/coverage.info
+          token: ${{ secrets.CODECOV_TOKEN }}

ci/docker/vt.dockerfile

@@ -48,6 +48,7 @@ ARG CACHE_ID=${IMAGE}
 ENV GIT_BRANCH=${GIT_BRANCH}
 
 RUN --mount=type=cache,id=${CACHE_ID},target=/build/ccache \
+    --mount=type=cache,id=BUILD-${CACHE_ID},target=/build/vt \
     --mount=target=/vt,rw \
         if [ "${VT_TEST_SPACK}" = "1" ]; then \
             apt update -y -q && apt install -y -q libssl-dev unzip && \

ci/test_cpp.sh

@@ -14,17 +14,10 @@ ctest --output-on-failure -L 'unit_test|example' | tee cmake-output.log
 
 if test "${VT_CODE_COVERAGE:-0}" -eq 1
 then
-    if [ -z "$CODECOV_TOKEN" ]; then
-        echo "Error: CODECOV_TOKEN is not set"
-        exit 1
-    fi
     export CODECOV_TOKEN="$CODECOV_TOKEN"
     lcov --capture --directory . --output-file coverage.info
     lcov --remove coverage.info '/usr/*' --output-file coverage.info
     lcov --list coverage.info
-    pushd "$VT"
-    bash <(curl -s https://codecov.io/bash) -r DARMA-tasking/vt -f "${VT_BUILD}/coverage.info" || echo "Codecov did not collect coverage reports"
-    popd
 fi
 
 if test "${VT_CI_TEST_LB_SCHEMA:-0}" -eq 1