GSOC report: Ruma procedural macro refactoring and more

2020-09-16 — GSOC — Devin Ragotzy

This is part of a series of reports on the six projects assigned to Matrix for Google Summer of Code 2020.

View project: Ruma procedural macro refactoring and more


Wow the summer has flown by, it feels like just yesterday I was learning how to rebase and what exactly it is Ruma does. I exaggerate slightly, but it is a big library with lots of public API surface. I have learned more in the last few months than in two years of school. I have been able to observe and participate in a project with a community growing around it, been a part of discussions about design and best practices, given and received numerous code reviews as well as learned the process of addressing the feedback, and working from a specification. In short, this has been an amazing opportunity to gain experience in all the things that are hard to obtain in a classroom.

My project goal was to improve the existing macros in ruma-events-macros and ruma-api-macros. It became clear early on that this would include some major API changes and that improving the macros as they were was pointless without also moving to a new public API. While improving the durability and readability of the macro code I also rewrote entire sections to accommodate the new design.

A quick overview of the Matrix protocol for reference: a client sends content that is interpreted by the server as events. The server distributes those events out to other clients and other servers (the server case is known as federation). Ruma groups these events by kind Message, State, Ephemeral, ToDevice and Basic which are represented as generic structs (StateEvent<C>). Each event kind needs to be able to hold many different content types, for state events there is room creation, room name, and membership events to name a few. Using the macros, enums are generated to represent all state event possibilities, so a variant for membership, room name, etc. These types exist to support the core API request and response types for each endpoint that is defined by the Matrix specification.

GSoC Starts and I start with ruma-events

More work on ruma-events, now a part of the new mono-repo

Work on ruma-client-api

Back to ruma-events

Continuing maintenance

One of my personal goals was to become more familiar with git. With the help of my mentor I now feel more confident using this tool that is so essential to developers. I became fairly adept at merging, rebasing, and navigating all the headaches that come with that. I learned plenty of new commands. A few highlights: cherry-pick and specific uses of reset to avoid copy-pasting fixes and adding more commits. I used the reset command to craft good commits, splitting work into appropriate chunks. I am glad that I had the opportunity to hone my git skills. I feel like I have accomplished my goal and then some!

I am proud of the work that I have done: Being part of moving ruma-events much closer to the 0.22 release and creating macros to generate types specific to the Matrix specification. Working with the community that has grown around Ruma has been rewarding and I plan on sticking around.