libexpat/CONTRIBUTING.md

Hi! 👋

Thanks for your interest in contributing to the libexpat project or "Expat"! 👍

Tip

TL;DR: The best move before creating a pull request that is big, complex, and/or controversial is to open a new issue and discuss options moving forward 🙏 🍻

Below, I'll document what Expat needs and does not need, at this time.

What Expat needs (and does not need) in general

Expat is:

• in maintenance mode,
• unfunded,
• understaffed,
• complex,
• 25+ years old in some regards,
• meant to support parsing of XML files that exceed available RAM,
• written in the memory-unsafe language C99,
• is used in many places, both in hardware and in software,
• implementing XML 1.0 Fourth Edition,
• targeting environments that are relevant today and/or up to 5 years into the past.

What kinds of pull requests will be welcome

Pull requests will be most welcome when they:

• are small,
• are easy to review,
• have low risk,
• have had GitHub Actions CI run and all-green already in your public fork repository,
• help both you and the libexpat project 🎉

The need for additional tests or CI will depend on the specific pull request.

What kinds of pull requests will not be welcome

Pull requests will not be welcome when:

• the changes are big, complex, high risk, controversial and/or hard to review,
• the exact change has been said "no" to in the past,
• the changes break API or ABI backwards compatibility,
• it fixes an issue for an unsupported (or no-longer supported) environment, and/or
• it introduces new features (without prior discussion and agreement in a dedicated issue).

Specific examples of things known to not be welcome:

• Mass-changing things.
• Fixing things for some stone age version of Visual Studio.
• Adding support to ignore or recover from malformed XML.
• Adding support for XML streaming.
• Making the C code compile with a C++ compiler.
• Adding support for XML 1.0r5 without prior discussion.
• Adding support for XML 1.1 in general.
• Adding additional build systems.

What Expat needs on a technical level

• All new C code and changes to existing C code must:
  • pass all existing CI (that includes ASan, UBSan, clang-format, Cppcheck, codespell, ..),
  • conform to C99,
  • check returns from malloc/realloc for NULL,
  • not use recursion (when it can be controlled by user input),
  • have integer overflow in mind,
  • have undefined behavior in mind, and
  • have security in mind in general.
• A commit should be about one — and just one — of these things:
  • fixing a bug,
  • improving something,
  • adding something new,
  • doing a refactoring, or
  • adjusting whitespace.

Providing feedback

Thanks for your interest and attention! 👍

I'm happy about constructive feedback to this document — thank you! 🙏