ci: upload Codecov only after all test jobs finish (#155)

* ci: upload Codecov after all tests complete

* chore(ci): bump artifact actions

Author: MilesCranmer

.github/workflows/CI.yml

@@ -54,10 +54,12 @@ jobs:
             julia --color=yes --threads=auto --check-bounds=yes --depwarn=yes --code-coverage=user -e 'import Coverage; import Pkg; Pkg.activate("."); Pkg.test(coverage=true)'
             julia --color=yes coverage.jl
         shell: bash
-      - uses: codecov/codecov-action@v5
+      - name: Upload coverage artifact
+        if: success()
+        uses: actions/upload-artifact@v6
         with:
-          token: ${{ secrets.CODECOV_TOKEN }}
-          files: lcov.info
+          name: coverage-${{ matrix.os }}-julia-${{ matrix.julia-version }}
+          path: lcov.info
 
 
   additional_tests:
@@ -89,8 +91,37 @@ jobs:
             SR_TEST=${{ matrix.test_name }} julia --color=yes --threads=auto --check-bounds=yes --depwarn=yes --code-coverage=user -e 'import Coverage; import Pkg; Pkg.activate("."); Pkg.test(coverage=true)'
             julia --color=yes coverage.jl
         shell: bash
-      - uses: codecov/codecov-action@v5
+      - name: Upload coverage artifact
         if: steps.run-tests.outcome == 'success'
+        uses: actions/upload-artifact@v6
+        with:
+          name: coverage-${{ matrix.test_name }}-${{ matrix.os }}-julia-${{ matrix.julia-version }}
+          path: lcov.info
+
+
+  codecov:
+    name: Upload combined coverage to Codecov
+    runs-on: ubuntu-latest
+    needs:
+      - test
+      - additional_tests
+    steps:
+      - name: Download coverage artifacts
+        uses: actions/download-artifact@v7
+        with:
+          pattern: coverage-*
+          path: coverage
+
+      - name: Merge lcov files
+        run: |
+          set -euxo pipefail
+          cd coverage
+          find . -name 'lcov.info' -print
+          cat $(find . -name 'lcov.info' -print | sort) > merged-lcov.info
+          wc -l merged-lcov.info
+
+      - name: Upload to Codecov
+        uses: codecov/codecov-action@v5
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
-          files: lcov.info
+          files: coverage/merged-lcov.info