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rr | devtools | |
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98 | 44 | |
8,569 | 648 | |
1.2% | 1.9% | |
9.6 | 9.9 | |
about 11 hours ago | 1 day ago | |
C++ | TypeScript | |
GNU General Public License v3.0 or later | GNU General Public License v3.0 or later |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
rr
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So you think you want to write a deterministic hypervisor?
https://rr-project.org/ had the same problem. They use the retired conditional branch counter instead of instruction counter, and then instruction steeping until at the correct address.
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Is Something Bugging You?
That'll work great for your Distributed QSort Incorporated startup, where the only product is a sorting algorithm.
Formal software verification is very useful. But what can be usefully formalized is rather limited, and what can be formalized correctly in practice is even more limited. That means you need to restrict your scope to something sane and useful. As a result, in the real world running thousands of tests is practically useful. (Well, it depends on what those tests are; it's easy to write 1000s of tests that either test the same thing, or only test the things that will pass and not the things that would fail.) They are especially useful if running in a mode where the unexpected happens often, as it sounds like this system can do. (It's reminiscent of rr's chaos mode -- https://rr-project.org/ linking to https://robert.ocallahan.org/2016/02/introducing-rr-chaos-mo... )
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When "letting it crash" is not enough
The approach of check-pointing computation such that it is resumable and restartable sounds similar to a time-traveling debugger, like rr or WinDbg:
https://learn.microsoft.com/windows-hardware/drivers/debugge...
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When I got started I debugged using printf() today I debug with print()
https://rr-project.org
This is indeed a problem people have with debuggers, so some very smart people found a way to fix it.
...and you're not on Linux, because on Linux we have rr! https://rr-project.org/
(I still use print statements 99.99% of the time though)
- OpenBSD KDE Plasma Desktop
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Firefox 118
> I've heard Linux support was down to like one guy [...]
Linux support is down to you. It's down to all of us. Install rr (https://rr-project.org/) and capture a crash with it.
Then you can replay the crash, find out that it's actually crashing in your closed-source graphics driver, which will motivate you to switch to an open source driver and fix your issue.
Also, while you're at it, update your linux kernel and wayland. They've both had bugs that could manifest as random firefox crashes in the last several months.
- A Modern C Development Environment
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Raku: A Language for Gremlins
I imagine you are referring to https://rr-project.org/ ?
Had never heard of it, looks pretty amazing, I might actually enjoy debugging now!
devtools
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Is Something Bugging You?
Exactly - that's what we've already built for web development at https://replay.io :)
I did a "Learn with Jason" show discussion that covered the concepts of Replay, how to use it, and how it works:
- https://www.learnwithjason.dev/travel-through-time-to-debug-...
Not only is the debugger itself time-traveling, but those time-travel capabilities are exposed by our backend API:
- https://static.replay.io/protocol/
Our entire debugging frontend is built on that API. We've also started to build new advanced features that leverage that API in unique ways, like our React and Redux DevTools integration and "Jump to Code" feature:
- https://blog.replay.io/how-we-rebuilt-react-devtools-with-re...
- https://blog.isquaredsoftware.com/2023/10/presentations-reac...
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Weird Debugging Tricks the Browser Doesn't Want You to Know
Replay's founders originally worked as engineers on the Firefox DevTools (and in fact our debugger client UI started as a fork of the FF Devtools codebase, although at this point we've rewritten basically every single feature over the last year and a half). So, the original Replay implementation started as a feature built into Firefox, and thus the current Replay recording browser you'd download has been our fork of Firefox with all the recording capabilities built in.
But, Chromium is the dominant browser today. It's what consumers use, it's devs use for daily development, and it's what testing tools like Cypress and Playwright default to running your tests in. So, we're in the process of getting our Chromium fork up to parity with Firefox.
Currently, our Chromium for Linux fork is fully stable in terms of actual recording capability, and we use it extensively for recording E2E tests for ourselves and for customers. (in fact, if you want to, all the E2E recordings for our own PRs are public - you could pop open any of the recordings from this PR I merged yesterday [0] and debug how the tests ran in CI.)
But, our Chromium fork does not yet have the UI in place to let a user manually log in and hit "Record" themselves, the way the Firefox fork does. It actually automatically records each tab you open, saves the recordings locally, and then you use our CLI tool to upload them to your account. We're actually working on this "Record" button _right now_ and hope to have that available in the next few weeks.
Meanwhile, our Chrome for Mac and Windows forks are in early alpha, and the runtime team is focusing on stability and performance.
Our goal is to get the manual recording capabilities in place ASAP so we can switch over and make Chromium the default browser you'd download to make recordings as an individual developer. It's already the default for configuring E2E test setups to record replays, since the interactive UI piece isn't necessary there.
Also, many of the new time-travel-powered features that we're building rely on capabilities exposed by our Chromium fork, which the Firefox fork doesn't have. That includes the improved React DevTools support I've built over the last year, which relies on our time-travel backend API to extract React component tree data, and then does post-processing to enable nifty things like sourcemapping original component names even if you recorded a production app. I did a talk just a couple weeks ago at React Advanced about how I built that feature [1]. Meanwhile, my teammate Brian Vaughn, who was formerly on the React core team and built most of the current React DevTools browser extension UI, has just rebuilt our React DevTools UI components and started to integrate time-travel capabilities. He just got a working example of highlighting which props/hooks/state changed for a selected component, and we've got some other neat features like jumping between each time a component rendered coming soon. All that relies on data extracted from Chromium-based recordings.
[0] https://github.com/replayio/devtools/pull/9885#issuecomment-...
[1] https://blog.isquaredsoftware.com/2023/10/presentations-reac...
- Evading JavaScript Anti-Debugging Techniques
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Why does the `useSyncExternalStore`docs example call `getSnapshot` 6 times on store update?
I made a Replay recording of the sandbox:
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Firefox displayed a pop-up ad for Mozilla VPN over an unrelated page
FWIW, the Firefox devs who were doing the WebReplay time travel debugging POC weren't, as far as I know, fired. Instead, they left and started Replay ( https://replay.io ), a true time-traveling debugger for JavaScript.
I joined Replay as a senior front-end dev a year ago. It's real, it works, we're building it, and it's genuinely life-changing as a developer :)
Not sure how well this would have fit into Firefox as a specific feature, given both the browser C++ runtime customizations and cloud wizardry needed to make this work. But kinda like Rust, it's a thing that spun out of Mozilla and has taken on a life of its own.
Obligatory sales pitch while I'm writing this:
The basic idea of Replay: Use our special browser to make a recording of your app, load the recording in our debugger, and you can pause at any point in the recording. In fact, you can add print statements to any line of code, and it will show you what it would have printed _every time that line of code ran_!
From there, you can jump to any of those print statement hits, and do typical step debugging and inspection of variables. So, it's the best of both worlds - you can use print statements and step debugging, together, at any point in time in the recording.
See https://replay.io/record-bugs for the getting started steps to use Replay, or drop by our Discord at https://replay.io/discord and ask questions.
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What is not taught in React courses, but is commonly used in a real job and overlooked?
I also recently did a Learn with Jason show episode based on this, where we went through many of the same topics, and also looked at the Replay.io time-traveling debugger that I build as my day job:
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Dan Abramov responds to React critics
My day job is working at a company called Replay ( https://replay.io ), and we're building a true "time traveling debugger" for JS. Our app is meant to help simplify debugging scenarios by making it easy to record, reproduce and investigate your code.
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Introducing Suspense: APIs to simplify data loading and caching, for use with React Suspense.
Not directly, no. Brian used to be part of the React core team, but he (and I) both joined https://replay.io last year. We've built up these utils as we've been refactoring our codebase, and Brian extracted them into their own package.
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Omniscient Debugging
Yep, my day job is working on the Replay time-traveling debugger for JS ( https://replay.io/ ).
Also saw someone post an indie gaming company's TTD development environment yesterday:
https://www.reddit.com/r/programming/comments/11a2meo/tomorr...
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Tomorrow Corporation's time travelling debugger, including debugging other people's play sessions, hot asset reloading, live compilation on every keystroke and more
I actually work for Replay ( https://replay.io ), where we're building a time-traveling debugger for JS apps. It's interesting to hear some of the similarities and differences in approaches and usages, since this is the kind of thing I work with on a daily basis myself.
What are some alternatives?
CodeLLDB - A native debugger extension for VSCode based on LLDB
gef - GEF (GDB Enhanced Features) - a modern experience for GDB with advanced debugging capabilities for exploit devs & reverse engineers on Linux
rrweb - record and replay the web
Module Linker - browse modules by clicking directly on "import" statements on GitHub
nbdev - Create delightful software with Jupyter Notebooks
clog-cli - Generate beautiful changelogs from your Git commit history
rustfmt - Format Rust code
Clippy - A bunch of lints to catch common mistakes and improve your Rust code. Book: https://doc.rust-lang.org/clippy/
quickjs-emscripten - Safely execute untrusted Javascript in your Javascript, and execute synchronous code that uses async functions
just - 🤖 Just a command runner
rustfix - Automatically apply the suggestions made by rustc
FlatBuffers - FlatBuffers: Memory Efficient Serialization Library