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{ Category Archives } Debugging

The joy of integrated logging and log viewing with fancy logs

The deuxdrop messaging experiment‘s current incarnation exists as an (under development) Jetpack that runs in Firefox.  I am still trying to shake out functionality to be driven by the UI rather than headless unit tests.  While firebug has been a great help, another boon has been the logging framework and log viewing framework developed for […]

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new adventures in rich (execution) logs for debugging and program understanding

Understanding what is going on inside software can be very hard, even for the developers most familiar with the software.  During my time working on Thunderbird I used a variety of techniques to try and peer inside: printf/dump/console.log, debuggers, execution analysis (dtrace, chronicle recorder, with object diffs, on timelines), logging (log4j style, with  timelines, with […]

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unified JS/C++ backtraces, colorized backtraces, colorized source listing for gdb 7.3/archer-trunk updated

gdb has had integrated python support for some time and it is truly awesome.  The innards have changed here and there, so my previous efforts to show colorized/fancy backtraces, show colorized source listings, and provide unified JS/C++ mozilla backtraces (with colors still) have experienced some bit-rot over time. I have de-bitrotted the changes, hard.  Hard […]

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teaser: Rich contextual information for Thunderbird mozmill failures

Sometimes Thunderbird mozmill unit tests fail.  When they do, it’s frequently a mystery.  My logsploder work helped reduce the mystery for my local mozmill test runs, but did nothing for tinderbox runs or developers without tool fever.  Thanks to recent renewed activity on the Thunderbird front-end, this has become more of a problem and so […]

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why so slow, pushlog?

I am doing something where I need to talk to the Mozilla hg pushlog.  I noticed things were running disturbingly slow, so I figured I’d look into it.  I’m using node.js so htracr (a node.js, libpcap-based via node_pcap http transaction visualizer) seemed like the easiest and most fun way to figure out what is going […]

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logsploder, circa a year+ ago

Whoops.  I posted to mozilla.dev.apps.thunderbird about an updated version of logsploder at the end of 2009, but forgot to blog about it.  I do so now (briefly) for my own retrospective interest and those who like cropped screenshots. The gloda (global database) tests and various Thunderbird mozmill tests have been augmented for some time (1+ […]

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Visualizing asynchronous JavaScript promises (Q-style Promises/B)

Asynchronous JS can be unwieldy and confusing.  Specifically, callbacks can be unwieldy, especially when you introduce error handling and start chaining asynchronous operations.  So, people frequently turn to something like Python’s Twisted‘s deferreds which provide for explicit error handling and the ability for ‘callbacks’ to return yet another asynchronous operation. In CommonJS-land, there are proposals […]

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understanding where layout goes wrong with gecko reflow debug logs (Part 2)

In part 1, I was fighting some kind of flex-box layout problem in gecko that I put on the metaphorical back burner.  The metaphorical pot is back, but rebuilt because the old pot did not support animation using CSS transitions.  (I was using overflow: none in combination with scrollLeft/scrollTop to scroll the directly contained children; […]

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wmsy’s debug UI’s decision tree visualizer

wmsy, the Widget Manifesting SYstem, figures out what widget to display by having widgets specify the constraints for situations in which they are applicable.  (Yes, this is an outgrowth of an earlier life involving multiple dispatch.)  Code that wants to bind an object into a widget provides the static, unchanging context/constraints at definition time and […]

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fighting oranges with systemtap probes, latency fighting; step 2

Recap from step 1: Sometimes unit test failures on the mozilla tinderboxen are (allegedly, per me) due to insufficiently constrained asynchronous processes.  Sometimes the tests time out because of the asynchronous ordering thing, sometimes it’s just because they’re slow.  Systemtap is awesome.  Using systemtap we can get exciting debug output in JSON form which we […]

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