debug: update PATH of Linux and MacOS builds

.github/workflows/publish_pypi.yml

@@ -130,7 +130,6 @@ jobs:
         run: |
           sudo apt-get update
           sudo apt-get install -y ccache
-          which ccache
 
       - name: Ccache cache
         uses: actions/cache@v4
@@ -156,6 +155,7 @@ jobs:
             mkdir -p $(pwd)/sundials_KLU_libs/lib64/
             export LD_LIBRARY_PATH=$(pwd)/sundials_KLU_libs/lib64/:$LD_LIBRARY_PATH
             export PATH=$(pwd)/sundials_KLU_libs/lib64/:$PATH
+            export PATH=/usr/bin/ccache:$PATH
             echo "LD_LIBRARY_PATH: $LD_LIBRARY_PATH"
 
             python -m pip install cmake casadi scikit-build-core pybind11
@@ -191,6 +191,17 @@ jobs:
       - name: Set macOS-specific environment variables
         run: echo "MACOSX_DEPLOYMENT_TARGET=11.0" >> $GITHUB_ENV
 
+      - name: Install ccache on MacOS
+        run: brew install ccache
+
+      - name: Ccache cache
+        uses: actions/cache@v4
+        with:
+          path: ${{ github.workspace }}/.ccache
+          key:  ${{ runner.os }}-ccache-${{ hashFiles('**/*.cpp', '**/*.h') }}
+          restore-keys:  ${{ runner.os }}-ccache-
+      - run: ccache -z
+
       - name: Build wheels on macOS
         uses: pypa/[email protected]
         with:
@@ -272,8 +283,7 @@ jobs:
             install_name_tool -id $(pwd)/sundials_KLU_libs/lib/libomp.dylib $(pwd)/sundials_KLU_libs/lib/libomp.dylib
             codesign --force --sign - $(pwd)/sundials_KLU_libs/lib/libomp.dylib
 
-            brew install ccache
-
+            export PATH=/opt/homebrew/opt/ccache/libexec:$PATH
             export CC=/usr/bin/clang
             export CXX=/usr/bin/clang++
             export CPPFLAGS="$CPPFLAGS -Xpreprocessor -fopenmp"
@@ -299,6 +309,9 @@ jobs:
             set -e -x
             python -c "import pybamm; print(pybamm.IDAKLUSolver())"
 
+      - name: Show ccache statistics
+        run: ccache -s
+
       - name: Upload wheels for macOS (amd64, arm64)
         uses: actions/[email protected]
         with: