difflog 0.0.2.dev0

A static analysis tool for diffing public Python APIs.

Difflog

Automated Changelog Generation via API Diffing for Python Projects

Difflog simplifies the task of generating changelogs by using static analysis to detect API-level changes in Python scripts. It outputs a concise Markdown changelog, ideal for release notes or CI/CD workflows.

Example integration: See .github/workflows/changes.yml

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Installation

Install Difflog via pip:

pip install difflog

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Detecting API Changes Between Files

Given two versions of a Python script:

main1.py

def main():
    print("Hello, world!")

if __name__ == "__main__":
    main()

main2.py

def main(name: str):
    print("Hello, world! My name is", name)

if __name__ == "__main__":
    main("John")
    print("Goodbye, world!")

Run the following command to detect API differences:

python -m difflog main1.py main2.py

Example output:

[main] Added positional or keyword argument `name`

For more examples, see tests/test_api_diffing.py

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Generating a Markdown Changelog from Git

If you're working in a Git repository, you can generate a changelog based on file-level API changes between commits:

difflog.git_report > CHANGES.md

This will:

• Analyze code changes since the last Git push
• Output a changelog in GitHub's Markdown format to CHANGES.md

You can also specify a revision range:

difflog.git_report --from-rev v1.0.0 --to-rev HEAD > CHANGES.md

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Programmatic API Usage

Use Difflog as a Python module for custom workflows, e.g., filtering changes, customizing output formats, etc.

import difflog

with open("old_file.py") as f:
    old_code = f.read()

with open("new_file.py") as f:
    new_code = f.read()

for change in difflog.diff(old_code, new_code):
    print(change)

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Contributing

Contributions are welcome! To contribute:

1. Fork the repository
2. Create a new branch
3. Submit a pull request

See existing issues or open a new one to discuss your ideas.

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License

Licensed under the Apache License 2.0. See LICENSE for details.

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Acknowledgments

Difflog leverages the excellent DeepDiff library for structural diffing.