Sync Python checks with "template" assets (#103)

We have assembled a collection of reusable project assets:
https://github.com/arduino/tooling-project-assets
These will be used in the repositories of all Arduino tooling projects.

Some improvements and standardizations have been made in the upstream "template" assets for checking Python files. Those
are introduced to this repository here.

Notable:

- Bump Python version used by the workflow from 3.8 to 3.9
- Add check for black formatting compliance
- Bump black formatting tool dependency to ^21.7b0
- Add pep8-naming flake8 plugin to check for Python naming convention compliance
- Add flake8 problem matcher to prominently surface linting violations in diffs, workflow run summary and logs

Author: per1234

.flake8

@@ -1,9 +1,12 @@
+# Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/check-python/.flake8
+# See: https://flake8.pycqa.org/en/latest/user/configuration.html
+# The code style defined in this file is the official standardized style to be used in all Arduino tooling projects and
+# should not be modified.
+
 [flake8]
 doctests = True
-ignore =
-    # W503 and W504 are mutually exclusive, so one or the other must be ignored.
-    # PEP 8 recommends line break before, so we keep W504.
-    W503
+# W503 and W504 are mutually exclusive. PEP 8 recommends line break before.
+ignore = W503
 max-complexity = 10
 max-line-length = 120
 select = E,W,F,C,N

.github/workflows/check-python-task.yml

@@ -0,0 +1,86 @@
+# Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/check-python-task.md
+name: Check Python
+
+env:
+  # See: https://github.com/actions/setup-python/tree/v2#available-versions-of-python
+  PYTHON_VERSION: "3.9"
+
+# See: https://docs.github.com/en/actions/reference/events-that-trigger-workflows
+on:
+  push:
+    paths:
+      - ".github/workflows/check-python-task.ya?ml"
+      - "**/.flake8"
+      - "**/poetry.lock"
+      - "**/pyproject.toml"
+      - "**/setup.cfg"
+      - "Taskfile.ya?ml"
+      - "**/tox.ini"
+      - "**.py"
+  pull_request:
+    paths:
+      - ".github/workflows/check-python-task.ya?ml"
+      - "**/.flake8"
+      - "**/poetry.lock"
+      - "**/pyproject.toml"
+      - "**/setup.cfg"
+      - "Taskfile.ya?ml"
+      - "**/tox.ini"
+      - "**.py"
+  workflow_dispatch:
+  repository_dispatch:
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Install Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ env.PYTHON_VERSION }}
+
+      - name: Install Poetry
+        run: pip install poetry
+
+      - name: Install Task
+        uses: arduino/setup-task@v1
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          version: 3.x
+
+      - name: Run flake8
+        uses: liskin/gh-problem-matcher-wrap@v1
+        with:
+          linters: flake8
+          run: task python:lint
+
+  formatting:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Install Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ env.PYTHON_VERSION }}
+
+      - name: Install Poetry
+        run: pip install poetry
+
+      - name: Install Task
+        uses: arduino/setup-task@v1
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          version: 3.x
+
+      - name: Format Python code
+        run: task python:format
+
+      - name: Check formatting
+        run: git diff --color --exit-code

.github/workflows/lint-python.yml

@@ -4,6 +4,7 @@ includes:
   dist: ./DistTasks.yml
 
 tasks:
+  # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/poetry-task/Taskfile.yml
   poetry:install-deps:
     desc: Install dependencies managed by Poetry
     cmds:
@@ -190,16 +191,20 @@ tasks:
     cmds:
       - task: python:lint
 
+  # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/check-python-task/Taskfile.yml
   python:lint:
     desc: Lint Python code
-    cmds:
+    deps:
       - task: poetry:install-deps
-      - poetry run flake8
+    cmds:
+      - poetry run flake8 --show-source
 
+  # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/check-python-task/Taskfile.yml
   python:format:
-    desc: Automatically formats Python files
-    cmds:
+    desc: Format Python files
+    deps:
       - task: poetry:install-deps
+    cmds:
       - poetry run black .
 
 vars:

Taskfile.yml

@@ -13,13 +13,14 @@ python-dateutil = "^2.8.1"
 
 [tool.poetry.dev-dependencies]
 flake8 = "^3.9.2"
-black = "^21.5b1"
+black = "^21.7b0"
 mkdocs = "^1.2.1"
 mkdocs-material = "^7.1.8"
 mdx-truly-sane-lists = "^1.2"
 click = "<7.2"
 GitPython = "^3.1.1"
 mike = "^1.0.1"
+pep8-naming = "^0.12.1"
 
 [tool.black]
 line-length = 120