hermit VS devtools

https://github.com/facebookexperimental/hermit but it hasn't worked for me and is now unmaintained.

That's been my experience as well. It lacks support for certain clone(2) flags like CLONE_VFORK[1], which limits the set of non-trivial programs it can run, and since running non-trivial programs is most of the point, I haven't revisited it since it was first announced.

[1] https://github.com/facebookexperimental/hermit/blob/bd3153b4...

A Meta developer responded to an issue of mine on Hermit, and said:

"Just to let you know we're not actively working on Hermit in the team..."

https://github.com/facebookexperimental/hermit/issues/34#iss...

I really like antithesis' approach: it's non-intrusive as all the changes are on a VM so one can run deterministic simulation without changing their code. It's also technically challenging, as making a VM suitable for deterministic simulation is not an easy feat.

On a side, I was wondering how this approach compares to Meta's Hermit(https://github.com/facebookexperimental/hermit), which is a deterministic Linux instead of a VM.

> AMA!

Eager to try it but encountering the build error here - https://github.com/facebookexperimental/hermit/issues/11

Do you have a reference build log / environment you can share? Last known good commit sha and/or output from "rustup show"?

Here is the GitHub repository: https://github.com/facebookexperimental/hermit

Have you ever been able to try https://replay.io time travel debugging as an alternative to conventional logging?

Last time I tried it you were able to add logging statements "after the fact" (i.e. after reproducing the bug) and see what they would have printed. I believe they also have the ability to act like a conventional debugger.

I think they're changing some aspects of their business model but the core record / replay tech is really cool.

Not at this time. I'm pretty full up at this point with day job ( https://replay.io ), conferences, and personal life stuff.

My current ongoing Redux maintenance task is trying to revamp our "Redux Essentials" tutorial to be TS-first. Making slower progress on that than I'd wanted, but hopefully can get that wrapped up in the not _too_ distant future.

Beyond that, we've got a ton of open RTK Query feature requests that I'd like to address later on this year.

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...

- https://github.com/Replayio/Protocol-Examples

I made a Replay recording of the sandbox:

Hiya folks! In addition to all my free time spent working on Redux, answering questions, and modding this sub, my day job is working on Replay.io. Today we're thrilled to announce our new Replay for Test Suites feature, which lets you record and time-travel debug Cypress (and Playwright) E2E tests as they ran in CI!

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.

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: