ci: Split coverage calculation (pola-rs#15780)

.github/workflows/codecov.yml

@@ -20,36 +20,22 @@ concurrency:
 
 defaults:
   run:
-    working-directory: py-polars
     shell: bash
 
+env:
+  RUSTFLAGS: '-C instrument-coverage --cfg=coverage --cfg=coverage_nightly --cfg=trybuild_no_target'
+  RUST_BACKTRACE: 1
+  LLVM_PROFILE_FILE: '/Users/runner/work/polars/polars/target/polars-%p-%3m.profraw'
+  CARGO_LLVM_COV: 1
+  CARGO_LLVM_COV_SHOW_ENV: 1
+  CARGO_LLVM_COV_TARGET_DIR: '/Users/runner/work/polars/polars/target'
+
 jobs:
-  coverage:
-    name: Code Coverage
+  coverage-rust:
     runs-on: macos-latest
-    env:
-      RUSTFLAGS: '-C instrument-coverage --cfg=coverage --cfg=coverage_nightly --cfg=trybuild_no_target'
-      RUST_BACKTRACE: 1
-      LLVM_PROFILE_FILE: '/Users/runner/work/polars/polars/target/polars-%p-%3m.profraw'
-      CARGO_LLVM_COV: 1
-      CARGO_LLVM_COV_SHOW_ENV: 1
-      CARGO_LLVM_COV_TARGET_DIR: '/Users/runner/work/polars/polars/target'
-
     steps:
       - uses: actions/checkout@v4
 
-      - uses: actions/setup-python@v5
-        with:
-          python-version: '3.10'
-
-      - name: Create virtual environment
-        run: |
-          python -m venv .venv
-          echo "$GITHUB_WORKSPACE/py-polars/.venv/bin" >> $GITHUB_PATH
-
-      - name: Install dependencies
-        run: pip install -r requirements-dev.txt
-
       - name: Set up Rust
         run: rustup component add llvm-tools-preview
 
@@ -79,28 +65,87 @@ jobs:
           -p polars-time
           -p polars-utils
 
-      - name: Run Rust integration tests
+      - name: Run integration tests
         run: cargo test --all-features -p polars --test it
 
+      - name: Report coverage
+        run: cargo llvm-cov report --lcov --output-path coverage-rust.lcov
+
+      - name: Upload coverage report
+        uses: actions/upload-artifact@v4
+        with:
+          name: coverage-rust
+          path: coverage-rust.lcov
+
+  coverage-python:
+    runs-on: macos-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.10'
+
+      - name: Create virtual environment
+        run: |
+          python -m venv .venv
+          echo "$GITHUB_WORKSPACE/.venv/bin" >> $GITHUB_PATH
+
+      - name: Install dependencies
+        run: pip install -r py-polars/requirements-dev.txt
+
+      - name: Set up Rust
+        run: rustup component add llvm-tools-preview
+
+      - name: Install cargo-llvm-cov
+        uses: taiki-e/install-action@cargo-llvm-cov
+
+      - name: Cache Rust
+        uses: Swatinem/rust-cache@v2
+        with:
+          save-if: ${{ github.ref_name == 'main' }}
+
+      - name: Prepare coverage
+        run: cargo llvm-cov clean --workspace
+
       - name: Install Polars
-        run: maturin develop
+        run: maturin develop -m py-polars/Cargo.toml
 
       - name: Run Python tests
+        working-directory: py-polars
         run: pytest --cov -n auto --dist loadgroup -m "not benchmark and not docs" --cov-report xml:main.xml
         continue-on-error: true
 
       - name: Run Python tests - async reader
+        working-directory: py-polars
         env:
           POLARS_FORCE_ASYNC: 1
         run: pytest --cov -m "not benchmark and not docs" tests/unit/io/ --cov-report xml:async.xml
         continue-on-error: true
 
-      - name: Report coverage
-        run: cargo llvm-cov report --lcov --output-path coverage.lcov
+      - name: Report Rust coverage
+        run: cargo llvm-cov report --lcov --output-path coverage-python.lcov
+
+      - name: Upload coverage reports
+        uses: actions/upload-artifact@v4
+        with:
+          name: coverage-python
+          path: |
+            coverage-python.lcov
+            py-polars/main.xml
+            py-polars/async.xml
+
+  upload-coverage:
+    needs: [coverage-rust, coverage-python]
+    runs-on: ubuntu-latest
+    steps:
+      - name: Download coverage files
+        uses: actions/download-artifact@v4
+        with:
+          merge-multiple: true
 
       - name: Upload coverage information
         uses: codecov/codecov-action@v4
         with:
-          files: py-polars/coverage.lcov,py-polars/main.xml,py-polars/async.xml
-          name: macos
+          files: coverage-rust.lcov,coverage-python.lcov,main.xml,async.xml
           token: ${{ secrets.CODECOV_TOKEN }}