Add Python autoformatter (no actual formatting yet)

Author: multiplemonomials

.github/workflows/basic_checks.yml

@@ -86,26 +86,20 @@ jobs:
 
   style-check:
     runs-on: ubuntu-latest
-    container:
-      image: ghcr.io/armmbed/mbed-os-env:master-latest
-
     steps:
 
       - name: Checkout repo
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           fetch-depth: 0
 
-      - 
-        name: UTF-8 Check
+      - name: UTF-8 Check
         run: |
           git config --global --add safe.directory "$GITHUB_WORKSPACE"
           # Make sure we're not introducing any text which is not UTF-8 encoded
           git diff origin/${GITHUB_BASE_REF} -U0 | ( grep -a '^+' || true ) | ( ! grep -axv '.*' )
-          
 
-      - 
-        name: astyle checks
+      - name: astyle checks
         run: |
           set -x
           git config --global --add safe.directory "$GITHUB_WORKSPACE"
@@ -134,11 +128,28 @@ jobs:
           tee BUILD/badlibs |
           sed -e "s/^/Bad library name found: /" && [ ! -s BUILD/badlibs ]
           # Assert that all assembler files are named correctly
-          # The strange command below asserts that there are exactly 0 libraries
+          # The strange command below asserts that there are exactly 0 files
           # that do end with .s
           find  -name "*.s" | tee BUILD/badasm |
           sed -e "s/^/Bad Assembler file name found: /" && [ ! -s BUILD/badasm ]
 
+      # Set up the oldest python version that's currently still supported by Python (as of Fall 2025)
+      - uses: actions/setup-python@v6
+        with:
+          python-version: '3.9'
+
+      - name: Install Python packages
+        run: |
+          python3 -m venv venv
+          source venv/bin/activate
+          pip install -e ./tools[linters]
+
+      - name: Check Python Formatting
+        run: |
+          cd tools
+          ruff format --diff
+          
+
   docs-check:
     runs-on: ubuntu-latest
 
@@ -162,14 +173,13 @@ jobs:
   python-tests:
     runs-on: ubuntu-latest
     steps:
-      -
-        name: Checkout repo
-        uses: actions/checkout@v4
-        
-      - name: Install python3-venv
-        run: |
-          sudo apt-get update
-          sudo apt-get install -y python3-venv
+      - name: Checkout repo
+        uses: actions/checkout@v5
+
+      # Set up the oldest python version that's currently still supported by Python (as of Fall 2025)
+      - uses: actions/setup-python@v6
+        with:
+          python-version: '3.9'
 
       - name: Install Python packages
         run: |

tools/pyproject.toml

@@ -71,6 +71,9 @@ unit-tests = [
     "beautifulsoup4",
     "lxml"
 ]
+linters = [
+    "ruff"
+]
 greentea = [
     ## Additional requirements to install into the Mbed environment when running Greentea tests
     # For USB Device host tests
@@ -103,3 +106,8 @@ mbedls = "mbed_lstools.main:mbedls_main"
 mbed-tools = "mbed_tools.cli.main:cli"
 memap = "memap.memap:main"
 ambiq_svl = "ambiq_svl.svl:cli"
+
+[tool.ruff]
+line-length = 120
+show-fixes = true
+src = ['python']

tools/run_python_linters.sh

@@ -0,0 +1,31 @@
+#!/bin/bash -e
+
+#
+# Copyright (c) 2025 Jamie Smith.
+# SPDX-License-Identifier: Apache-2.0
+#
+
+# Script which runs Python formatters and linters
+# This is executed by the GitHub Actions CI build but also can be run locally.
+
+# Go to script directory
+cd "$(dirname $0)"
+
+# Activate Mbed OS virtualenv
+if command -v mbedhtrun >/dev/null 2>&1; then
+  echo "Mbed OS python environment appears to already be activated."
+elif [ -e "../venv/Scripts/activate" ]; then
+  source "../venv/Scripts/activate"
+elif [ -e "../venv/bin/activate" ]; then
+  source "../venv/bin/activate"
+else
+  echo "Failed to find Mbed OS virtualenv in ../venv and Python packages not installed to global environment."
+  exit 1
+fi
+
+if ! command -v ruff >/dev/null 2>&1; then
+  echo "Linters optional dependency of Mbed not installed. Please run 'mbed-os/venv/bin/pip install mbed-os/tools[linters]'."
+fi
+
+echo ">> Formatting with Ruff..."
+ruff format