Enable caching of Python environments and pip download caches

.github/workflows/python-package.yml

@@ -20,7 +20,41 @@ jobs:
  wheel-path: ${{ steps.get-darker-version.outputs.wheel-path }}
  steps:
  - uses: actions/checkout@v4
- - uses: actions/setup-python@v5
+ - id: setup-python
+ uses: actions/setup-python@v5
+
+ # PYTHON CACHING:
+ - id: python-cache
+ uses: actions/cache@v4
+ with:
+ path: |
+ ${{ env.pythonLocation }}/lib
+ ${{ env.pythonLocation }}/bin
+ key: >
+ os${{ runner.os }}-
+ py${{ steps.setup-python.outputs.python-version }}-
+ req${{ hashFiles('setup.cfg') }}
+ - id: get-pip-cache
+ if: steps.python-cache.outputs.cache-hit != 'true'
+ run: echo "pip-cache-dir=$(pip cache dir)" >> ${GITHUB_OUTPUT}
+ - name: "Cache pip"
+ if: steps.python-cache.outputs.cache-hit != 'true'
+ uses: actions/cache@v4
+ with:
+ path: ${{steps.get-pip-cache.outputs.pip-cache-dir}}
+ key: >
+ os${{ runner.os }}-
+ py${{ steps.setup-python.outputs.python-version }}-
+ req${{ hashFiles('setup.cfg') }}
+ restore-keys: "\
+ os${{ runner.os }}-\
+ py${{ steps.setup-python.outputs.python-version }}-
+
+ os${{ runner.os }}-
+
+ "
+ # END PYTHON CACHING
+
  - name: Install wheel
  run: python -m pip install wheel
  - name: Build wheel distribution
@@ -119,10 +153,44 @@ jobs:
  with:
  fetch-depth: 0
  # need full history since Pytest runs Darker itself below
- - name: Set up Python ${{ matrix.python-version }}
+ - id: setup-python
+ name: Set up Python ${{ matrix.python-version }}
  uses: actions/setup-python@v5
  with:
  python-version: ${{ matrix.python-version }}
+
+ # PYTHON CACHING:
+ - id: python-cache
+ uses: actions/cache@v4
+ with:
+ path: |
+ ${{ env.pythonLocation }}/lib
+ ${{ env.pythonLocation }}/bin
+ key: >
+ os${{ runner.os }}-
+ py${{ steps.setup-python.outputs.python-version }}-
+ req${{ hashFiles('setup.cfg') }}
+ - id: get-pip-cache
+ if: steps.python-cache.outputs.cache-hit != 'true'
+ run: echo "pip-cache-dir=$(pip cache dir)" >> ${GITHUB_OUTPUT}
+ - name: "Cache pip"
+ if: steps.python-cache.outputs.cache-hit != 'true'
+ uses: actions/cache@v4
+ with:
+ path: ${{steps.get-pip-cache.outputs.pip-cache-dir}}
+ key: >
+ os${{ runner.os }}-
+ py${{ steps.setup-python.outputs.python-version }}-
+ req${{ hashFiles('setup.cfg') }}
+ restore-keys: "\
+ os${{ runner.os }}-\
+ py${{ steps.setup-python.outputs.python-version }}-
+
+ os${{ runner.os }}-
+
+ "
+ # END PYTHON CACHING
+
  - name: Download wheel uploaded by the build-wheel job
  uses: actions/download-artifact@v3
  - name: Install Darker and its dependencies from the wheel built earlier
@@ -146,7 +214,41 @@ jobs:
  - build-wheel
  steps:
  - uses: actions/checkout@v4
- - uses: actions/setup-python@v5
+ - id: setup-python
+ uses: actions/setup-python@v5
+
+ # PYTHON CACHING:
+ - id: python-cache
+ uses: actions/cache@v4
+ with:
+ path: |
+ ${{ env.pythonLocation }}/lib
+ ${{ env.pythonLocation }}/bin
+ key: >
+ os${{ runner.os }}-
+ py${{ steps.setup-python.outputs.python-version }}-
+ req${{ hashFiles('setup.cfg') }}
+ - id: get-pip-cache
+ if: steps.python-cache.outputs.cache-hit != 'true'
+ run: echo "pip-cache-dir=$(pip cache dir)" >> ${GITHUB_OUTPUT}
+ - name: "Cache pip"
+ if: steps.python-cache.outputs.cache-hit != 'true'
+ uses: actions/cache@v4
+ with:
+ path: ${{steps.get-pip-cache.outputs.pip-cache-dir}}
+ key: >
+ os${{ runner.os }}-
+ py${{ steps.setup-python.outputs.python-version }}-
+ req${{ hashFiles('setup.cfg') }}
+ restore-keys: "\
+ os${{ runner.os }}-\
+ py${{ steps.setup-python.outputs.python-version }}-
+
+ os${{ runner.os }}-
+
+ "
+ # END PYTHON CACHING
+
  - name: Install twine
  run: python -m pip install twine
  - name: Download wheel uploaded by the build-wheel job