These are short stories from bug hunts and incident investigations at Wikipedia. Impact After developers submit code to Gerrit, they eagerly await the result from Jenkins, an automated test runner. Every day during the 15 minute window...

These are short stories from bug hunts and incident investigations at Wikipedia. New database partition A user reported a timeout error for certain queries from the Public log viewer on commons.wikimedia.org. Database administrator...

This week saw the conclusion of a project that I’ve been shepherding on and off since September of last year. The goal was for the initialisation of our asynchronous JavaScript pipeline (at the time, 36 kilobytes in size) to fit within a...

What’s the worst that could happen after npm install? When you open an app or execute a program from the terminal, that program can do anything that you can do. In a nutshell: Imagine if your computer were to disappear in front of your...

Six years ago (in 2012), I was looking for a newsletter about browser releases. At the time, my motivation was to remember to regularly check and update the jQuery TestSwarm framework as needed for each new browser release. I found a...

This post shows how we measure and interpret load times on Wikipedia. It also explains what real-user metrics are, and how percentiles work. Navigation Timing When a browser loads a page, the page can include program code (JavaScript)....

Today, I’d like to challenge the assert.ok and assert.not* methods. I believe they may’ve become an anti-pattern. assert.ok Using assert.ok() indicates one of two problems: The former necessitates improvement to the code being tested....

How did Apple create Safari, and what is PhantomJS? Safari In January 2003 Apple announced Safari, their new web browser for Mac. The Safari team had just spent 2002 building Safari atop KHTML and KJS, the KDE layout and javascript...

re·buke verb express sharp disapproval or criticism of (someone) because of their behavior or actions “she had rebuked him for drinking too much“ “the judge publicly rebuked the jury“ noun an expression of sharp disapproval or criticism...