1/5 Last week I mentioned I'd also share a demo of @_pernosco_, which is a debugger whose interface is designed for record-and-replay debugging, although the debugging itself is less about replay than about moving between program states of interest.
L. David Baron @dbaron@w3c.social @davidbaron
22 Dec 2021
1/ Record-and-replay debugging has changed the way I work as a software engineer working on browser engines. I made a video showing how I used rr to debug one bug in Chromium. drive.google.com/file/d/15Ef… Some Chromium colleagues found this useful, so I'm sharing it here too.
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2/5 I recorded myself debugging (re-debugging, really) in pernosco. The bug turned out to be pretty simple; something that I perhaps should have figured out by looking at the code. However, I think it makes a reasonable demo of debugging in pernosco: drive.google.com/file/d/19TY…

pernosco demo 1 (debugging SynthesizedClipLayerCount() unittest failure).mp4

drive.google.com
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3/5 The bulk of my rr demo video was really doing something that was a single logical operation: tracing backwards to find where a value comes from. One of my favorite parts of this pernosco video is near the opening, where I show that this becomes a few clicks in pernosco.
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4/5 Another one of my favorite pieces of this video was entirely unintentional: I made a mistake and ended up in the wrong state. To fix this mistake, I just hit the browser's back button. Web technology (used well) really does have advantages.

Dec 28, 2021 · 2:31 PM UTC

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5/5 A few more links: Pernosco: pernos.co/ The change I was debugging (which now contains the fix for the bug, but still isn't submitted): crrev.com/c/3307117

Pernosco

Fast, fun, omniscient debugging. Record failures anywhere, rapidly debug recordings using the revolutionary Pernosco omniscient debugger, and share your recordings and debugging state with other...

pernos.co
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