Catching regressions faster

February 10th, 2010

My latest post on the Mozilla Security Blog:

Fixing security holes without introducing new bugs

Safety agency announces “Safety is our top priority”

February 6th, 2010

This press release is the top item on right now:

WASHINGTON, D.C. – The National Highway Traffic Safety Administration (NHTSA) today announced that it is opening a formal investigation of the Toyota Prius Hybrid model year 2010 to look into allegations of momentary loss of braking capability while traveling over an uneven road surface, pothole or bump.

The Office of Defects Investigation has received 124 reports from consumers, including four reports alleging that crashes occurred. Investigators have spoken with consumers and conducted pre-investigatory field work.

“Safety is our top priority,” said Secretary Ray LaHood. “That is why in recent weeks NHTSA has also issued a consumer advisory on the recall of several models of Toyota vehicles and the Pontiac Vibe involving pedal entrapment and sticky accelerator pedals. We will continue to monitor these issues closely.”

To be fair, Ray LaHood is the secretary of the Department of Transportation, of which the NHTSA is only a part. Maybe he was speaking on behalf of the entire Department of Transportation, in which case he was just repeating a meaningless platitude. But that's hard to see from the press release.

Downloadable debug builds

January 14th, 2010

Testers can now download debug builds of Firefox rather than going trough the complicated process of building Firefox themselves.

Debug builds have extra code called assertions to inform us when assumptions or surrounding code are incorrect. For example, assertions can reliably tell us when third-party code makes common threading mistakes, even though the crashes from those mistakes appear random. I find about a third of my bugs by noticing assertion failures, and it usually isn't the assertion that's incorrect.

In several bug reports from users who were hitting frequent crashes at random, I suggested that the users compile their own debug builds, hoping that assertion failure messages would lead us to the cause of the crash. Few of the users succeeded, since the compilation tools and instructions were written with programmers in mind. Now that pre-made debug builds are available, we may be able to make more progress on these kinds of crash bug reports.

Big thanks to the release engineering team for making these builds available!

Shorter URLs for

January 14th, 2010

Reed Loden set up as a redirect for Bugzilla bugs and searches. Examples:

Fun with DOMMouseScroll

November 6th, 2009

I put together a demo of incrementing numbers in URLs by scrolling.

Hopefully it's not considered a bug that I can use rangeOffset for a text node "inside" a textbox ;) Trying to access rangeParent throws a security exception.

This could be used by an extension like URL Flipper as a shortcut for changing specific numbers in URLs.

Replacing my weekly review

November 2nd, 2009

Getting Things Done recommends spending an hour or two on a "weekly review" every Friday afternoon. This worked for me at first, but after a month, I found myself procrastinating more often than actually doing a weekly review. Ironically, another concept from the same book helped me understand some of the reasons.

A major problem with my old weekly review checklist was that it included things I had to do in different contexts. For example, I can only check snail mail at home, but I can only check voice mail when I'm not at home. Worse, performing a weekly review seemed to require concentrating on one thing for an hour, and I'd rather spend that concentration on programming.

I decided to split my weekly review into a list of weekly sanity reminders, with each reminder on appropriate day of the week. I chose Monday for reviewing actions assigned to specific contexts, since the contexts "office" and "business-hours" usually become available on Monday. But I review coding projects later in the week, when distractions have died down.

For many of the smaller parts of my old weekly review, such as making sure my iPhone's voicemail list is empty, I chose a day of the week on which a mid-day meeting breaks up my day.

Splitting my weekly review into multiple scheduled items allowed me to put some reminders on the days when they do the most good, and others on the days when distractions do the least harm.

Like the author of GTD, I found that doing each of these things once a week helps me focus on the right projects and avoid some forms of procrastination. They just don't all need to be done on the same day.

Subscribing to a file in hg

October 16th, 2009

Yesterday, I subscribed to the hg feed for reftest.js in Google Reader. Today, Google Reader informed me of a change Mats made. It works!

Buglist in input order

October 15th, 2009

My newest Greasemonkey script, Buglist in input order, lets you sort a bug list according to an order external to Bugzilla.

For example, you can view the list of bugs related to topcrashes sorted by how common each crash is. First, load the list of Firefox 3.5.3 topcrashes. Second, use the "collect buglinks" bookmarklet to view a bug list consisting of the bug numbers listed there. Third, click the "#" added by this Greasemonkey script to sort the bugs by their order on the topcrash page.

Hopefully, this script will allow us to avoid duplicating information between Bugzilla and CrashKill wiki pages, and thus reduce the risk of information in both places becoming out of date.