CI: Add lint-py action (verilator#4640)

.github/workflows/lint.yaml

@@ -0,0 +1,53 @@
+# DESCRIPTION: Github actions config
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+name: lint
+
+on:
+  push:
+  pull_request:
+  workflow_dispatch:
+  schedule:
+  - cron: '0 0 * * 0' # weekly
+
+env:
+  CI_OS_NAME: linux
+  CI_COMMIT: ${{ github.sha }}
+
+defaults:
+  run:
+    shell: bash
+    working-directory: repo
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event_name == 'pull_request' && github.ref || github.run_id }}
+  cancel-in-progress: true
+
+jobs:
+
+  lint-py:
+    runs-on: ubuntu-22.04
+    name: Lint Python
+    env:
+      CI_BUILD_STAGE_NAME: build
+      CI_RUNS_ON: ubuntu-22.04
+      CI_M32: 0
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v3
+      with:
+        path: repo
+
+    - name: Install packages for build
+      run: ./ci/ci-install.bash
+
+    # We use specific version numbers, otherwise a Python package
+    # update may add a warning and break our build
+    - name: Install packages for lint
+      run: sudo pip3 install pylint==3.0.2 ruff==0.1.3 clang sphinx sphinx_rtd_theme sphinxcontrib-spelling breathe ruff
+
+    - name: Configure
+      run: autoconf && ./configure --enable-longtests --enable-ccwarn
+
+    - name: Lint
+      run: make -k lint-py

Makefile.in

@@ -434,9 +434,15 @@ PYLINT_FLAGS = --score=n --disable=R0801
 RUFF = ruff
 RUFF_FLAGS = check --ignore=E402,E501,E701
 
+# "make -k" so can see all tool result errors
 lint-py:
-	-$(PYLINT) $(PYLINT_FLAGS) $(PY_PROGRAMS)
-	-$(RUFF) $(RUFF_FLAGS) $(PY_PROGRAMS)
+	$(MAKE) -k lint-py-pylint lint-py-ruff
+
+lint-py-pylint:
+	$(PYLINT) $(PYLINT_FLAGS) $(PY_PROGRAMS)
+
+lint-py-ruff:
+	$(RUFF) $(RUFF_FLAGS) $(PY_PROGRAMS)
 
 format-pl-exec:
 	-chmod a+x test_regress/t/*.pl