debut: Utilities to parse Debian package, copyright and control files

The Python package debut is a collection of utilities to parse various Debian package manifests, machine readable copyright and control files collectively known as the Debian 822 format (based on the RFC822 email format).

Why the name debut? That's a portmanteau of DEBian and UTilities!

Origin

This library is based on a heavily modified and remixed combination of original code with code from other origins:

• python-deb-pkg-tools from @xolox for its handling of Debian packages and the parsing of dependencies and other package-to-package relationship fields. See

• dlt (Debian license tools) from @agustinhenze for its check of the coverage of a license file Files sections and a lot of inspiration. See

• PGPy from @SecurityInnovation and @Commod0re for its ability to remove a PGP signature from an email. dsc (Debian Source Control) files are typically PGP-signed. See

• python-dpkg by @TheClimateCorporation and @memory for its ability to process the syntax of Debian versions and to compare them according to the spec. See

Why?

Why create this seemingly redundant library? The official python-debian tools and several other utilities already provide similar capabilities!

On the surface this is correct, but there are several reasons for a new utility:

• Existing tools parse control files strictly. This library tries to be more flexible. For instance it can recognize and fix some almost correct copyright files that are not fully "machine readable" but close enough to the spec to be worthy of recovery.
• Several of these tools have to deal with legacy compatibility. We do not have such a need. For instance, the Python standard library email module and one line of code is enough to parse a Debian 822 file fields. I doubt that this feature was available in the standard library when python-debian was started but it is here now and this vastly simplifies the code.
• The focus of this library is to parse and inspect control files, not to emit and create them, so the code and tests can be much simpler. For instance, rather than using more complex case-insensitive dictionary keys while preserving case for Deb822-like objects, this library uses lower case keys throughout.
• The official python-debian library is GPL-licensed making it it hard to combine with Apache-licensed libraries. I tried to work out a licensing change for python-debian with all its authors such that it could be integrated in permissive-licensed Python tools. Even though most current maintainers and contributors were OK with that relicensing to a permissive or an LGPL license, I could not get a reply and agreement from some important legacy authors: therefore the relicensing was not possible.

License

SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause AND MIT

This software combines software from several origins with different licenses. All of these licenses apply as all original files have been refactored and remixed significantly:

Copyright nexB Inc. and others.
Copyright (c) 2018 Peter Odding.
Copyright 2017 The Climate Corporation (https://climate.com)
Copyright (c) 2014-2019 Security Innovation, Inc
Copyright 2013 Agustin Henze 

Note that the tests/ may also contain files using other FOSS licenses.