@codacy/tools-pylint-3

Table of Contents

• Overview
• Updating patterns
• Updating the Pylint version
• Development
• Notes for maintainers

Overview

Python static analyzer using the Pylint binary. Uses the CLI execution strategy — installs pylint into a dedicated venv, spawns it via spawnTool(), and parses its JSON2 output.

| Property | Value | |----------|-------| | Tool ID | PyLintPython3 | | Codacy UUID | 31677b6d-4ae0-4f56-8041-606a8d7a8e61 | | Strategy | CLI | | Languages | Python | | Binary | pylint | | File patterns | **/*.py | | Pattern count | ~340 | | Prerequisites | Python 3.8+ |

Updating patterns

# Re-fetch pattern metadata from the Codacy API
pnpm prefetch

# Commit the result
git add src/patterns.json

Pattern IDs follow the format PyLintPython3_C0114, PyLintPython3_E0602, etc.

Updating the Pylint version

1. Update PREFERRED_VERSION and the pylint==X.Y.Z entry in PIP_PACKAGES in src/adapter.ts
2. Run pnpm prefetch to check for new/removed rules
3. Run pnpm test to verify compatibility
4. If the major version changes, create a new adapter package (pylint-4/)

Development

pnpm build    # Build with tsup
pnpm test     # Run tests (requires pylint in PATH or auto-installed)

Install pylint manually for local development:

pip install pylint

Or let the adapter auto-install into a venv:

codacy-analysis analyze . --install-dependencies

The adapter installs these packages into the venv:

• pylint==3.3.9
• pylint-django
• pylint-flask
• pylint-celery
• pylint-common
• pylint-beam
• pylint-pytest
• SaltPyLint

Notes for maintainers

• JSON2 output format: The adapter uses --output-format=json2 which outputs { "messages": [...], "statistics": {...} }. This is the modern format (Pylint 3.x+).
• 0-based columns: Pylint reports columns as 0-based. The adapter adds 1 to convert to the 1-based model used by Codacy.
• Nullable endLine/endColumn: These fields can be null in Pylint output. The adapter omits them from Issue objects when null.
• Exit code bitmask: Pylint uses a bitmask exit code. Bit 5 (value 32) indicates a usage error (bad config/args). Bits 0-4 (values 1-31) indicate normal findings. The adapter checks exitCode & 32 to distinguish errors from normal findings.
• E0401 filtering: The E0401 (import-error) pattern is permanently filtered because sandboxed environments cannot resolve third-party imports. This matches the existing Codacy wrapper behavior.
• Plugin support: The adapter bundles the same plugins as the Codacy wrapper (pylint-django, pylint-flask, pylint-celery, pylint-common, pylint-beam, pylint-pytest, SaltPyLint).
• Pattern parameters: Some patterns accept parameters (e.g. max-line-length for C0301, max-locals for R0914). These are passed as --{param}={value} CLI arguments.
• Venv isolation: Pylint and its plugins are installed in a dedicated venv at ~/.codacy/runtimes/pylint-3/venv/ to avoid dependency conflicts with other Python tools.
• Config files: The adapter checks for pylintrc, .pylintrc, pylintrc.toml, .pylintrc.toml, pyproject.toml, and setup.cfg in that order.