SpiderMonkey Newsletter (Firefox 122-123)

Hello everyone!

Matthew Gaudet here from the SpiderMonkey team, giving Jan a break from newsletter writing.

Our newsletter is an opportunity to highlight some of the work that’s happened in SpiderMonkey land over the last couple of releases. Everyone is hard at work (though some of us are nicely rejuvenated from a winter break).

Feel free to email feedback on the shape of the newsletter to me, as I’d be interested in hearing what works for people and what doesn’t.

🚀 Performance

We’re continuing work on our performance story, with Speedometer 3 being the current main target. We like Speedometer 3 because it provides a set of workloads that we think better reflect the real web, driving improvements to real users too.

Here is a curated selection of just some of the performance related changes in this release:

🔦 Contributor Spotlight: Mayank Bansal

Mayank Bansal has been a huge help to the Firefox project for years. Taking a special interest in performance, he is often one of the first to take note of a performance improvement or regression. He also frequently files performance bugs, some of which have identified fixable problems, along with comparative profiles which smooth the investigative process.

In his own words:

Mayank Bansal has been using Firefox Nightly for more than a decade. He is passionate about browser performance and scours the internet for interesting javascript test-cases for the SM team to analyse. He closely monitors the performance improvement and regressions on AWFY. You can check out some of the bugs he has filed by visiting the metabug here.

The SpiderMonkey team greatly appreciates all the help we get from Mayank. Thank you very much Mayank.

⚡ Wasm

👷🏽‍♀️ Other Work

⏰ Date parsing improvements

Contributor Vinny Diehl has continued improving our date parsing story, aiming to improve compatibility and handling of peculiar cases.

🐇 Fuzzing

In order to find bugs, fuzzing by generating and running random testcases to see if they crash turns out to be an unreasonably effective technique. The SpiderMonkey team works with a variety of fuzzers, both inside of Mozilla (👋 Hi fuzzing@!) and outside (Thank you all!).

Fuzzing can find test cases which are both very benign but worth fixing, as well as extremely serious security bugs. Security sensitive fuzz bugs are eligible for the Mozilla Bug Bounty Program.

To show off the kind of fun we have with fuzzing, I thought I’d curate some fun, interesting (and not hidden for security reasons) fuzz bugs.