PyLint Configuration

This document covers all configuration options for the pylint-sort-functions plugin when used with PyLint.

Basic Setup

Plugin Loading

Add the plugin to your PyLint configuration:

.pylintrc:

[MASTER]
load-plugins = pylint_sort_functions

pyproject.toml:

[tool.pylint.MASTER]
load-plugins = ["pylint_sort_functions"]

setup.cfg:

[pylint]
load-plugins = pylint_sort_functions

Message Control

The plugin defines three message types that can be individually controlled:

Message Types

W9001: unsorted-functions

Functions in a module are not sorted alphabetically within their visibility scope.

W9002: unsorted-methods

Methods in a class are not sorted alphabetically within their visibility scope.

W9003: mixed-function-visibility

Public and private functions/methods are not properly separated.

Enabling Messages

.pylintrc:

[MESSAGES CONTROL]
# Enable all sorting messages
enable = unsorted-functions,unsorted-methods,mixed-function-visibility

# Or enable specific messages only
enable = unsorted-functions

pyproject.toml:

[tool.pylint."messages control"]
enable = [
    "unsorted-functions",
    "unsorted-methods",
    "mixed-function-visibility"
]

Disabling Messages

.pylintrc:

[MESSAGES CONTROL]
# Disable specific sorting messages
disable = unsorted-methods

# Disable all sorting messages
disable = unsorted-functions,unsorted-methods,mixed-function-visibility

pyproject.toml:

[tool.pylint."messages control"]
disable = ["unsorted-methods"]

Plugin-Specific Configuration

Decorator Exclusions

Configure patterns for decorators that should be excluded from sorting requirements. This is essential for framework compatibility where decorator order matters.

.pylintrc:

[pylint-sort-functions]
# Exclude Flask routes and Click commands
ignore-decorators = @app.route,@*.command,@pytest.fixture

# Multiple patterns on separate lines
ignore-decorators = @app.route
                   @*.command
                   @pytest.fixture

pyproject.toml:

[tool.pylint-sort-functions]
ignore-decorators = [
    "@app.route",
    "@*.command",
    "@pytest.fixture"
]

Privacy Detection Settings

Configure the privacy detection feature that suggests functions should be made private:

.pylintrc:

[pylint-sort-functions]
# Enable privacy detection (default: true)
check-privacy = yes

# Custom public API patterns (future feature)
public-patterns = main,run,execute,setup,teardown,init

pyproject.toml:

[tool.pylint-sort-functions]
check-privacy = true
public-patterns = ["main", "run", "execute", "setup", "teardown"]

Directory Exclusions

Configure which directories to skip during import analysis (future feature):

.pylintrc:

[pylint-sort-functions]
# Skip additional directories during analysis
skip-dirs = vendor,third_party,legacy

# Add to default skip list
additional-skip-dirs = custom_vendor,generated

pyproject.toml:

[tool.pylint-sort-functions]
skip-dirs = ["vendor", "third_party", "legacy"]
additional-skip-dirs = ["custom_vendor", "generated"]

Framework-Specific Configurations

Flask Applications

.pylintrc:

[MASTER]
load-plugins = pylint_sort_functions

[MESSAGES CONTROL]
enable = unsorted-functions,unsorted-methods,mixed-function-visibility

[pylint-sort-functions]
ignore-decorators = @app.route
                   @app.before_request
                   @app.after_request
                   @app.errorhandler
                   @app.teardown_appcontext

pyproject.toml:

[tool.pylint.MASTER]
load-plugins = ["pylint_sort_functions"]

[tool.pylint."messages control"]
enable = ["unsorted-functions", "unsorted-methods", "mixed-function-visibility"]

[tool.pylint-sort-functions]
ignore-decorators = [
    "@app.route",
    "@app.before_request",
    "@app.after_request",
    "@app.errorhandler",
    "@app.teardown_appcontext"
]

Click CLI Applications

.pylintrc:

[MASTER]
load-plugins = pylint_sort_functions

[pylint-sort-functions]
ignore-decorators = @*.command
                   @*.group
                   @*.option
                   @*.argument

pyproject.toml:

[tool.pylint-sort-functions]
ignore-decorators = [
    "@*.command",
    "@*.group",
    "@*.option",
    "@*.argument"
]

Django Applications

.pylintrc:

[pylint-sort-functions]
ignore-decorators = @login_required
                   @csrf_exempt
                   @require_http_methods
                   @cache_page
                   @vary_on_headers

FastAPI Applications

.pylintrc:

[pylint-sort-functions]
ignore-decorators = @app.get
                   @app.post
                   @app.put
                   @app.delete
                   @app.patch
                   @app.middleware

Pytest Test Configuration

.pylintrc:

[pylint-sort-functions]
ignore-decorators = @pytest.fixture
                   @pytest.mark.*
                   @pytest.parametrize

Integration Examples

CI/CD Pipeline

.github/workflows/lint.yml:

name: Code Quality
on: [push, pull_request]

jobs:
  pylint:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - name: Set up Python
        uses: actions/setup-python@v4
        with:
          python-version: '3.11'
      - name: Install dependencies
        run: |
          pip install pylint pylint-sort-functions
      - name: Run PyLint with sorting checks
        run: |
          pylint --load-plugins=pylint_sort_functions src/

Pre-commit Hooks

.pre-commit-config.yaml:

repos:
  - repo: local
    hooks:
      - id: pylint-sort-functions
        name: Check function sorting
        entry: pylint
        args: [--load-plugins=pylint_sort_functions, --disable=all, --enable=unsorted-functions,unsorted-methods,mixed-function-visibility]
        language: system
        files: \\.py$

Makefile Integration

Makefile:

.PHONY: lint-sorting
lint-sorting:
     pylint --load-plugins=pylint_sort_functions \
            --disable=all \
            --enable=unsorted-functions,unsorted-methods,mixed-function-visibility \
            src/

tox Configuration

tox.ini:

[testenv:lint]
deps =
    pylint
    pylint-sort-functions
commands =
    pylint --load-plugins=pylint_sort_functions src/

Advanced Configuration

Per-File Overrides

Use PyLint’s standard per-file configuration:

.pylintrc:

[MESSAGES CONTROL]
# Disable sorting checks for specific files
per-file-ignores =
    legacy_code.py:unsorted-functions,unsorted-methods
    third_party/*.py:unsorted-functions,unsorted-methods,mixed-function-visibility

Multiple Configuration Files

For projects with multiple components:

src/.pylintrc:

[MASTER]
load-plugins = pylint_sort_functions

[pylint-sort-functions]
ignore-decorators = @app.route

tests/.pylintrc:

[MASTER]
load-plugins = pylint_sort_functions

[pylint-sort-functions]
ignore-decorators = @pytest.fixture,@pytest.mark.*

Custom Message Formats

Customize how sorting messages are displayed:

.pylintrc:

[REPORTS]
msg-template = {path}:{line}:{column}: [{msg_id}({symbol})] {msg}

Output Configuration

JSON Output

For integration with other tools:

pylint --load-plugins=pylint_sort_functions --output-format=json src/

Parsing the output:

import json
import subprocess

result = subprocess.run([
    'pylint',
    '--load-plugins=pylint_sort_functions',
    '--output-format=json',
    'src/'
], capture_output=True, text=True)

messages = json.loads(result.stdout)
sorting_messages = [
    msg for msg in messages
    if msg['message-id'] in ['W9001', 'W9002', 'W9003']
]

Colorized Output

Enable colors in terminal output:

pylint --load-plugins=pylint_sort_functions --output-format=colorized src/

Troubleshooting

Plugin Not Loading

Error: No such message id 'unsorted-functions'

Solution: Ensure the plugin is properly loaded:

# Verify plugin loading
pylint --load-plugins=pylint_sort_functions --list-msgs | grep W900

Error: ImportError: No module named 'pylint_sort_functions'

Solution: Install the plugin:

pip install pylint-sort-functions

Configuration Not Applied

Issue: Configuration seems to be ignored

Solutions:

  1. Verify configuration file location:

    # PyLint searches in this order:
# 1. Command line: --rcfile=path/to/.pylintrc
# 2. Current directory: ./.pylintrc
# 3. Parent directories (recursively)
# 4. Home directory: ~/.pylintrc
# 5. /etc/pylintrc

  2. Test configuration loading:

    pylint --load-plugins=pylint_sort_functions --generate-rcfile

  3. Use explicit configuration:

    pylint --rcfile=.pylintrc --load-plugins=pylint_sort_functions src/

Performance Issues

For large projects, the import analysis may be slow:

.pylintrc:

[pylint-sort-functions]
# Disable privacy detection for better performance
check-privacy = no

Memory Usage

For very large codebases:

# Process directories individually
pylint --load-plugins=pylint_sort_functions src/module1/
pylint --load-plugins=pylint_sort_functions src/module2/