As the year is about to close, it's about time to say good-bye to Twitter. I'm not deleting the account or old tweets, I'll still monitor for mentions and DMs, and if something has _only_ been posted to Twitter I may retweet here. But all announcements will go elsewhere.

So basically, today PHP got two critical bugs that let anyone run code on your server without even logging in, which is bad, and then the details leaked before the patch was even out, which is worse, and it works on WordPress and MediaWiki and Magento and Joomla and Laravel, and Censys says like 1.5 million servers are running a version with no fix, so the NSA was like "take your system offline," and the FBI was like "take your system offline," and CISA and the UK and CERT-EU were all like "take your system offline," and then the Prime Minister of Japan, the actual Prime Minister, posted at 5:55 in the morning telling 48.8 million people to take their system offline, so everyone took their system offline, like the Dutch cybersecurity agency took its own website offline, and the Dutch parliament went offline, and the Port of Rotterdam went offline, and Finland and France and Denmark started pulling government sites, and Wikipedia went down, and Archive.org went down, and Asana and GOG and Something Awful went down, and the University of Vienna's webmail went down for some reason, and that's just PHP. Because GitLab also dropped a CVSS 10.0, which is the highest score they give out, for a bug that's been there since 2014, so that's every self-hosted GitLab for twelve years, and then LiteLLM 1.107.0 got hijacked and shipped a credential stealer and a remote access trojan in every single wheel and the Docker images, including latest, and you didn't even have to import it, just installing it was enough, and it's the second time this year, and then Railway paused every deployment on the entire platform because someone got into the environment variables, so now everyone has to rotate every secret they've ever stored there, and TiDB Cloud said someone was walking around inside with stolen credentials for basically a month and an extortion group says they took 10.6 terabytes, and Zeabur got breached for the second time in two months and is just shutting down, like the whole company, and Node.js patched remote code execution and a TLS bypass, and CISA says Plex is being actively exploited, and someone took over 300 Tor exit relays to steal SSH passwords, and SafePay ransomware has hit over 600 critical infrastructure orgs, and India's biggest bank filed a data loss incident, and Japan has been in an official state of emergency in cyberspace since October 9, which honestly explains the 5:55 AM post. Oh, and eMudhra, a certificate authority that's issued over 60 million certificates, whose entire job is proving websites are who they say they are, was supposed to be using private keys that are random numbers over a hundred digits long, and one of them was 4. Just 4. And the others were like 66 and 237. Anyway, it's Wednesday.

In January, @jonhoo, @jjgort, and I returned to @MIT_CSAIL to teach Missing Semester, a class on topics missing from most CS programs—tools and techniques that everyone should know, like Bash, Git, CI/CD, and AI tools. Today, we’re releasing the course for free online!

Should developers quit because of AI? 🤖

@VBragilevsky talked with @jonhoo about AI, programming, salaries, job market specifics, and of course, Rust 🦀

Watch the full interview for more insights 👉 jb.gg/JGrr25Xjb

#AI #JetBrains #SoftwareEngineering #RustRover #RustLang #Programming

Missing Semester has grown past 100K subscribers on YouTube. Appreciate all the engagement and support!

We plan to teach another iteration of the course in January 2026, revising the curriculum and covering new topics like AI IDEs and vibe coding.

How to be a Principal Engineer/Senior Principal Engineer/Senior Architect/fancy-sounding-title Engineer, a thread:

1. You're evaluated on how much more the company succeeds because you're there, not the lines of code you wrote. If you can unblock someone, do that. If you need to kill a two year project that's not going anywhere, do that. Do what is right, not what makes you look good.

As for where "elsewhere" is, they're all listed on jonhoo.eu, and at the time of writing includes YouTube, Discord, LinkedIn, Bluesky, and Mastodon. See you all there!

New year, new Q&A; 1/1 at 5:30pm UTC: everytimezone.com/s/03a3a76f.

Bring out your questions, however deep or superficial, and I'll do my best to answer 😅 Vote on questions and propose your own at wewerewondering.com/event/01JG4AMT… starting now!

Stream will be at youtube.com/live/eMuGHXMjJ… 🍿🙋

Perhaps unsurprisingly, I have a bunch of Opinions™ on work-life balance and time management. Lately, I've been particularly bugged by the common belief that employer incentives don't align with employee well-being. So, I wrote a thing (with graphs!): thesquareplanet.com/blog/about-40-…

Hey it's me Destin, from Smarter Every Day. Now that it's time to elect America's next leader, I would like to share something very interesting and important with you. I've been paying attention to this for a while, and I think if you look for it, you see it too.
🧵 1/n

🎥 The first #eurorust24 video is here! Starting off strong with @jonhoo , the Principal Engineer at @HelsingAI , as he teaches fundamental concepts of Rust that can be challenging for newcomers. It’s a masterclass in effective Rust education!

Btw, Jon 🦀 is also the author of Rust for Rustaceans and the creator of the Crust of Rust YouTube series 📺 buff.ly/4f44nED
Go and check out his other works!

Watch Jon's video here ➡️ buff.ly/3NO9DAf

#rustlang #techeducation #crustofrust

🎉 New and FREE at #eurorust24: Competitive Control Systems Hackathon by Helsing! Build a control system in Rust for a virtual quadcopter, compete live on a leaderboard, and test your creativity. Limited seats—grab yours now!

Mentors: Dr. Robert Fink, @jonhoo , Cécile Allano , t.co/oUgKxR2vl2

#rustlang

Recording of today's stream where we decrusted the quickcheck property testing crate is now up!
youtu.be/64t-gPC33cc

Short notice, but tomorrow @ 8am UTC (everytimezone.com/s/f47dc299) I'll decrust the quickcheck crate! We will explore what property testing is, how quickcheck lets you do it, how to go "more advanced", and how it all works under the hood.
Come join at youtube.com/live/53JgWT9Ug… 🦀

Time in your timezone:

The recording of the stream where we implemented a lexer and parser for the Lox language from Crafting Interpreters in Rust is now up, and I think it turned out really good! Clocked in at 8h, but it's split into chapters to not be so daunting to follow :)
youtu.be/mNOLaw-_Buc

Follow along or come up with your own solution first and then compare, whichever you prefer — you can access the challenge for free through app.codecrafters.io/join?via=jonhoo, or in free source form (without the nice infrastructure) at github.com/codecrafters-i….

I've been looking to stream writing an interpreter for a while, and @codecraftersio have just released a challenge in beta following @munificentbob's Crafting Interpreters book! So, this Saturday @ 1pm UTC (everytimezone.com/s/416927f0) we'll give it a try 🧑‍💻
youtube.com/live/FdZmJ0DAm…

Come join me live, or try it yourself and compare notes with the VOD after the fact! You can access the challenge over at app.codecrafters.io/join?via=jonhoo, or in free source form at github.com/codecrafters-i….

The Crafting Interpreters book is craftinginterpreters.com.

I was particularly inspired to do a stream like this after reading matklad's excellent article on Pratt parsing: matklad.github.io/2020/04/13/sim…