Add lint action

Author: PeterSurda

.github/workflows/tox-lint.yml

@@ -0,0 +1,69 @@
+name: Tox Linter Tests
+
+on:
+  push:
+    branches: [master, main, v0.6]
+  pull_request:
+    branches: [master, main, v0.6]
+
+jobs:
+  lint:
+    name: "${{ matrix.tox-env }} / python ${{ matrix.python-version }}"
+    runs-on: ubuntu-latest
+    container: ${{ matrix.container }}
+    strategy:
+      fail-fast: false
+      matrix:
+        tox-env: [lint-basic, lint]
+        python-version: ["2.7", "3.10"]
+        include:
+          - python-version: "2.7"
+            container: "python:2.7-buster"
+
+    steps:
+      # ── System packages ────────────────────────────────────────
+      # Container (Python 2): runs as root, needs git for checkout
+      - name: Install system dependencies (container)
+        if: matrix.python-version == '2.7'
+        run: |
+          apt-get update -q
+          apt-get install -qy git libcap-dev
+
+      # Host VM (Python 3): git is pre-installed, just need libcap-dev
+      - name: Install system dependencies
+        if: matrix.python-version != '2.7'
+        run: |
+          sudo apt-get update -q
+          sudo apt-get install -qy libcap-dev
+
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      # ── Python 3 ───────────────────────────────────────────────
+      - name: Set up Python ${{ matrix.python-version }}
+        if: matrix.python-version != '2.7'
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      # ── Python 2 ───────────────────────────────────────────────
+      - name: Override basepython for Python 2
+        if: matrix.python-version == '2.7'
+        run: sed -i 's/basepython = python3/basepython = python2.7/' tox.ini
+
+      - name: Pin Python 2 compatible linter versions
+        if: matrix.python-version == '2.7'
+        run: |
+          # flake8 >=5 and bandit >=1.7.5 dropped Python 2 support;
+          # pylint >=3 requires Python 3.8+
+          sed -i 's/^\(    bandit\)$/\1<1.7.5/'      tox.ini
+          sed -i 's/^\(    flake8\)$/\1<5.0.0/'      tox.ini
+          sed -i 's/^\(     pylint\)$/\1<2.0.0/'     tox.ini
+
+      # ── Common ─────────────────────────────────────────────────
+      - name: Install tox
+        run: |
+          pip install "tox<4" "virtualenv<20.22.0"
+
+      - name: Run tox -e ${{ matrix.tox-env }}
+        run: tox -e ${{ matrix.tox-env }}