Add pre-commit configuration file compatible with Trunk.io

[Copilot]

Overview

This PR adds a comprehensive .pre-commit-config.yaml file that integrates seamlessly with the existing Trunk.io setup in the repository. Pre-commit hooks provide automated code quality checks before commits, helping maintain consistent code standards across contributions.

What's Included

1. Pre-commit Configuration (.pre-commit-config.yaml)

A fully configured pre-commit setup with 6 repositories and 16 hooks:

Python Tools:

• Ruff v0.4.1 - Fast Python linting and formatting (replaces Black, isort, flake8)
• Bandit 1.7.8 - Security vulnerability scanning with project-specific config

Code Formatting:

• Prettier v3.1.0 - Formats YAML, JSON, and Markdown files consistently
• yamllint v1.35.1 - YAML linting using existing .trunk/configs/.yamllint.yaml
• markdownlint v0.39.0 - Markdown linting using existing .trunk/configs/.markdownlint.yaml

Standard Checks (v5.0.0):

• Large file detection, case conflicts, merge conflict markers
• YAML/JSON/TOML syntax validation
• End-of-file and trailing whitespace fixers
• Private key detection

2. GitHub Actions Workflow (.github/workflows/pre-commit.yml)

Automated pre-commit checks run on:

• All pull requests
• Pushes to the main branch

This ensures code quality standards are maintained in CI/CD pipelines.

3. Documentation Updates

Added a comprehensive "Development Setup" section to CONTRIBUTING.md with:

• Step-by-step installation instructions
• Usage examples for manual runs
• Complete list of configured hooks
• Integration notes with Trunk.io

Trunk.io Compatibility

This configuration is designed to work alongside Trunk.io, not replace it:

✅ Hook versions match those in .trunk/trunk.yaml
✅ Reuses existing Trunk configuration files
✅ Properly excludes test cassettes from linting
✅ TruffleHog and Commitlint commented out (handled by Trunk.io actions)
✅ Compatible with existing Trunk.io pre-commit and pre-push actions

Usage

Contributors can enable pre-commit hooks with:

pip install pre-commit
pre-commit install

Hooks will automatically run on every commit. Manual runs are also supported:

# Check all files
pre-commit run --all-files

# Check specific files
pre-commit run --files src/diffbot_kg/models.py

Benefits

• Catches issues early - Before commits reach CI/CD
• Consistent code quality - Automated formatting and linting
• Security scanning - Detects secrets and vulnerabilities
• Easy to use - Simple setup, automatic execution
• CI/CD integration - Automated checks on all PRs

Closes #[issue_number]

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Create a pre-commit YAML configuration file, compable with Trunk.io if possible</issue_title>
<issue_description></issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes #12

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[trunk-io]

Merging to main in this repository is managed by Trunk.

• To merge this pull request, check the box to the left or comment /trunk merge below.

[trunk-io]

Running Code Quality on PRs by uploading data to Trunk will soon be removed. You can still run checks on your PRs using trunk-action - see the migration guide for more information.

To fix the problem, you should add a permissions block that restricts the GITHUB_TOKEN permissions to the minimum required. For most pre-commit/CHECK-type jobs that only need to read repository code, setting permissions: contents: read suffices, unless the workflow specifically needs to write to pull requests or issues (which it does not appear to from the provided actions). The recommended approach is to add this permissions block at the workflow level (just after the name: and before on:), so it applies to all jobs unless otherwise specified. You should insert:

permissions:
  contents: read

at line 3, pushing the on: and subsequent lines down. No import or variable definition is necessary; just a change to the YAML structure.

[brendancsmith]

@copilot