What I Learned Contributing to .NET Runtime #135120 — Why More Developers Should Try Open Source

Contributing to the .NET Runtime was something I had wanted to try for a long time.

Recently, I opened PR #135120 in the dotnet/runtime repository.

https://github.com/dotnet/runtime/pull/135120

What surprised me most was not just the code change, but the engineering process behind making even a focused change in a large, production-grade open-source project.

WHAT I LEARNED

1. Reading source code is a skill

Before changing anything, I had to understand how the existing implementation worked and how the surrounding code was designed.

2. Tests tell a story

Existing tests helped me understand the expected behavior and gave me confidence that the change was not breaking existing scenarios.

3. Small changes can require deep investigation

A change that looks small from the outside can involve understanding implementation details, existing conventions, edge cases, and compatibility considerations.

4. Code review is part of the learning process

A pull request is not simply code submitted for approval. It is an opportunity to learn from developers who know the codebase extremely well.

5. You do not have to be an expert before contributing

This has probably been my biggest takeaway.

I used to think I needed to understand the entire .NET Runtime before contributing to it.

I don't.

You can start with one problem, investigate it deeply, and learn along the way.

MY QUESTION FOR THE .NET COMMUNITY

For developers who have contributed to .NET, ASP.NET Core, EF Core, or other major open-source projects:

What was your first contribution, and what did it teach you that you would not have learned from building your own applications?

I would love to hear your experiences and advice for developers who are considering their first open-source contribution.