Introduce ruff as linter and formatter (#601)

Previously, the project only ran `pycodestyle` in CI for style
checks and had no autoformatter, so formatting and import order were
enforced manually and inconsistently.

This change introduces `ruff` for both formatting and linting,
configured in `ruff.toml`, and replaces `pycodestyle` in CI. The
`CONTRIBUTING.md` is updated to document the new workflow.

The formatter enforces double quotes, space indentation, and
docstring code formatting (line length 120, target py310).

The following lint rule groups are enabled and the codebase was
fixed to comply:

- `E`/`W`: pycodestyle errors and warnings
- `I`: import order (isort)
- `F4`: imports and `__future__` usage
- `F5`: format strings (e.g. unnecessary f-strings)
- `F7`: control flow (`return`/`break`/`continue` placement)
- `F8`: undefined and unused names
- `D201`/`D204`/`D211`/`D300`: basic docstring formatting
- `COM818`: trailing comma enforcement
- `PIE`: small readability improvements
- `RUF100`: unused `noqa` statements

Several rule groups are ignored for now (see the `TODO` in
`ruff.toml`). Rules like `F403`/`F405` are ignored due to high
existing star-import usage, while groups such as `N` (naming), `B`
(bugbear), `S` (security), and `BLE` (blind except) are left for a
later evaluation of whether to promote them to linting.

Fixes #412

Author: JAB1305

.github/workflows/ci.yml

@@ -116,9 +116,6 @@ jobs:
     - name: Check typing with MyPy
       run: |
         python -m mypy basyx test
-    - name: Check code style with PyCodestyle
-      run: |
-        python -m pycodestyle --count --max-line-length 120 basyx test
 
   sdk-readme-codeblocks:
     # This job runs the same static code analysis (mypy and pycodestyle) on the codeblocks in our docstrings.
@@ -265,9 +262,6 @@ jobs:
     - name: Check typing with MyPy
       run: |
         python -m mypy aas_compliance_tool test
-    - name: Check code style with PyCodestyle
-      run: |
-        python -m pycodestyle --count --max-line-length 120 aas_compliance_tool test
 
   compliance-tool-package:
     # This job checks if we can build our compliance_tool package
@@ -316,9 +310,6 @@ jobs:
     - name: Check typing with MyPy
       run: |
         python -m mypy app test
-    - name: Check code style with PyCodestyle
-      run: |
-        python -m pycodestyle --count --max-line-length 120 app test
 
   server-repository-docker:
     # This job checks if we can build our server package

CONTRIBUTING.md

@@ -143,6 +143,8 @@ before new code can be added:
 - We run the developed unittests and aim for a code coverage of at least 80%.
 - We perform static code analysis for type-checking and codestyle, not just in the code itself, but also in codeblocks 
   that are inside docstrings and the `README.md`.
+- We apply a set of [ruff](https://docs.astral.sh/ruff/) linter rules (see [ruff.toml](ruff.toml)) to ensure a certain 
+  codestyle and prevent issues / bad practices to arise.
 - We check that the automatically generated developer documentation compiles.
 - We check that the Python Versions we support match between the different subprojects in the monorepository and are 
   not End of Life.
@@ -164,8 +166,8 @@ pip install .[dev]
 
 Running all checks:
 ```bash
+ruff check
 mypy basyx test
-pycodestyle --max-line-length 120 basyx test
 python -m unittest
 coverage run --source basyx --branch -m unittest
 coverage report -m
@@ -185,6 +187,7 @@ of it without error.
 For that, you need to have Docker installed on your system. 
 In the directory with the `Dockerfile`: 
 ```bash
+ruff check
 docker build -t basyx-python-server .
 docker run --name basyx-python-server basyx-python-server
 ```
@@ -204,8 +207,8 @@ itself.
 
 Then you can run the checks via:
 ```bash
+ruff check
 mypy basyx test
-pycodestyle --max-line-length 120 basyx test
 python -m unittest
 coverage run --source basyx --branch -m unittest
 coverage report -m

compliance_tool/aas_compliance_tool/cli.py

@@ -12,18 +12,17 @@
 """
 import argparse
 import datetime
-
 import logging
 
 import pyecma376_2
-
 from basyx.aas.adapter import aasx
-from basyx.aas.adapter.xml import write_aas_xml_file
-from aas_compliance_tool import compliance_check_xml as compliance_tool_xml, \
-    compliance_check_json as compliance_tool_json, \
-    compliance_check_aasx as compliance_tool_aasx
 from basyx.aas.adapter.json import write_aas_json_file
-from basyx.aas.examples.data import create_example, create_example_aas_binding, TEST_PDF_FILE
+from basyx.aas.adapter.xml import write_aas_xml_file
+from basyx.aas.examples.data import TEST_PDF_FILE, create_example, create_example_aas_binding
+
+from aas_compliance_tool import compliance_check_aasx as compliance_tool_aasx
+from aas_compliance_tool import compliance_check_json as compliance_tool_json
+from aas_compliance_tool import compliance_check_xml as compliance_tool_xml
 from aas_compliance_tool.state_manager import ComplianceToolStateManager, Status
 
 

compliance_tool/aas_compliance_tool/compliance_check_aasx.py

@@ -14,18 +14,15 @@
 import datetime
 import logging
 from typing import Optional, Tuple, cast
-import io
-from lxml import etree  # type: ignore
 
 import pyecma376_2
-
-from aas_compliance_tool import compliance_check_json, compliance_check_xml
 from basyx.aas import model
 from basyx.aas.adapter import aasx
-from basyx.aas.adapter.xml import xml_deserialization
 from basyx.aas.adapter.json import json_deserialization
-from basyx.aas.examples.data import example_aas, create_example_aas_binding
+from basyx.aas.adapter.xml import xml_deserialization
+from basyx.aas.examples.data import create_example_aas_binding, example_aas
 from basyx.aas.examples.data._helper import AASDataChecker, DataChecker
+
 from aas_compliance_tool.state_manager import ComplianceToolStateManager, Status
 
 

compliance_tool/aas_compliance_tool/compliance_check_json.py

@@ -11,15 +11,14 @@
 :class:`~basyx.aas.compliance_tool.state_manager.ComplianceToolStateManager` by adding new steps and associated
 :class:`LogRecords <logging.LogRecord>`
 """
-import os
-import json
 import logging
-from typing import Optional, IO
+from typing import Optional
 
-from basyx.aas import (model)
+from basyx.aas import model
 from basyx.aas.adapter.json import json_deserialization
-from basyx.aas.examples.data import example_aas, create_example
+from basyx.aas.examples.data import create_example, example_aas
 from basyx.aas.examples.data._helper import AASDataChecker
+
 from aas_compliance_tool.state_manager import ComplianceToolStateManager, Status
 
 

compliance_tool/aas_compliance_tool/compliance_check_xml.py

@@ -11,15 +11,14 @@
 :class:`~basyx.aas.compliance_tool.state_manager.ComplianceToolStateManager` by adding new steps and associated
 :class:`LogRecords <logging.LogRecord>`
 """
-import os
-from lxml import etree  # type: ignore
 import logging
 from typing import Optional
 
 from basyx.aas import model
 from basyx.aas.adapter.xml import xml_deserialization
-from basyx.aas.examples.data import example_aas, create_example
+from basyx.aas.examples.data import create_example, example_aas
 from basyx.aas.examples.data._helper import AASDataChecker
+
 from aas_compliance_tool.state_manager import ComplianceToolStateManager, Status
 
 

compliance_tool/aas_compliance_tool/state_manager.py

@@ -8,10 +8,11 @@
 This module defines a :class:`~.ComplianceToolStateManager` to store :class:`LogRecords <logging.LogRecord>`
 for single steps in a compliance check of the compliance tool
 """
-import logging
 import enum
+import logging
 import pprint
-from typing import List, Dict
+from typing import Dict, List
+
 from basyx.aas.examples.data._helper import DataChecker
 
 
@@ -25,6 +26,7 @@ class Status(enum.IntEnum):
     :cvar FAILED:
     :cvar NOT_EXECUTED:
     """
+
     SUCCESS = 0
     SUCCESS_WITH_WARNINGS = 1  # never used
     FAILED = 2
@@ -39,6 +41,7 @@ class Step:
     :ivar status: Status of the step from type Status
     :ivar log_list: List of :class:`LogRecords <logging.LogRecord>` which belong to this step
     """
+
     def __init__(self, name: str, status: Status, log_list: List[logging.LogRecord]):
         self.name = name
         self.status = status
@@ -65,6 +68,7 @@ class ComplianceToolStateManager(logging.Handler):
 
     :ivar steps: List of :class:`Steps <.Step>`
     """
+
     def __init__(self):
         """
         steps: List of steps. Each step consist of a step name, a step status and LogRecords belong to to this step.

compliance_tool/test/_test_helper.py

@@ -1,11 +1,10 @@
-import io
-from typing import Literal, Type, Optional
 import datetime
+import io
 import logging
+from typing import Literal, Optional, Type
 
 import pyecma376_2
-
-from basyx.aas.examples.data import create_example_aas_binding, TEST_PDF_FILE
+from basyx.aas.examples.data import TEST_PDF_FILE, create_example_aas_binding
 
 
 def create_example_aas_core_properties() -> pyecma376_2.OPCCoreProperties:

compliance_tool/test/test_aas_compliance_tool.py

@@ -7,12 +7,11 @@
 import datetime
 import hashlib
 import io
-import os
 import tempfile
 import unittest
 from contextlib import redirect_stderr, redirect_stdout
 from io import StringIO
-from unittest.mock import patch, ANY
+from unittest.mock import ANY, patch
 
 from aas_compliance_tool.cli import main, parse_cli_arguments
 from basyx.aas import model

compliance_tool/test/test_compliance_check_aasx.py

@@ -7,12 +7,12 @@
 import unittest
 from unittest import mock
 
-from ._test_helper import create_example_aas_core_properties, create_read_into_mock
 from aas_compliance_tool import compliance_check_aasx as compliance_tool
 from aas_compliance_tool.state_manager import ComplianceToolStateManager, Status
-
 from basyx.aas.examples.data._helper import CheckResult
 
+from ._test_helper import create_example_aas_core_properties, create_read_into_mock
+
 
 class ComplianceToolAASXTest(unittest.TestCase):