Team member here. Firefox Replay is currently in user research phase while we validate it.

Cross platform support will absolutely be a priority when Replay is on the official roadmap.

Thanks for the feedback, firefox-replay.com is also a work in progress. We did not plan an official release today.

We'll be sure to make the Mac OS limitation more clear.

Here is some more context on the mac specific functionality (https://searchfox.org/mozilla-central/source/toolkit/recordr...).

> Firefox Replay is currently in user research phase while we validate it

A question about how you develop / roll this out. Do you keep the code private, or do you commit it to the open source repo as you're working with a small amount high touch users?

I guess the question is do you want a full working product when you open source it? Do you tie your PR / forum posts with publicly shipping the source code? Or is all development out in the open?

Good question.

Everything is in firefox and open source

Here are the bugs: https://bugzilla.mozilla.org/buglist.cgi?cmdtype=runnamed&na...

Here's the primary directory: https://searchfox.org/mozilla-central/source/toolkit/recordr...

The debugger API is implemented in JS here https://searchfox.org/mozilla-central/source/devtools/server...

Thanks for the clarification and for building this great-sounding tool. I'm really looking forward to trying this out on Windows!

What benefits it provides than record and playback using a screen recorder?

Based on the linked MDN page (from the current top-rated comment) it sounds like the main point of this is to have a rewind-able debugger.

Retroactive logging.

Why not? A huge portion of developers uses Macs and windows support is coming at some point. Better to get an actual feedback from the developers.

People on HN don't seem to like it when some other companies start their product from one platform.

Nor do they like it when they do support all platforms from day one via an Electron app...

People on HN don't like anything.

Other people on HN like some things.

Speaking of which, I'm a little shocked to see a Mozilla thread that doesn't yet mention Pocket or the rebranding or DoH. That must mean we are in a good mood?

We're busy prepping to argue about UBI at Thanksgiving dinner.

Oh man. Now I really want to tell the wife to turn the car around.

No, just too busy talking about Linux on desktop!

Look again.

When that platform is Mac, certainly. For some mysterious reason you don't see complaints about Linux-only utilities :)

you can virtualize linux, you cannot virtualize macos.

no, downloading sketchy images or hacking your virtualization software does not count.

> you cannot virtualize macos.

You can, and it’s licensed to.

Since Lion:

> (iii) to install, use and run up to two (2) additional copies or instances of the Apple Software within virtual operating system environments on each Mac Computer you own or control that is already running the Apple Software.

No hassle support page on VMware site:

https://kb.vmware.com/s/article/1000131

EDIT: Amusingly on topic with gist of thread above, anger about a dev tool launched for MacOS, this fact with citations from license and support page from VMware garnered instant down votes.

Well if you can only virtualize it on a computer that's already running macos I don't know how that's supposed to help.

You can virtualize on a PC. Whether you may or not, depends whether you believe you own software.

And how it helps when you do it on MacOS on Mac hardware is letting you do all the things you virtualize an OS for, from a fine GUI on a decent kernel.

> all the things you virtualize an OS for

One of the main things I "virtualize an OS for" is to use software that requires Platform A on a system that runs Platform B. Running "legit" (authorized) virtualized MacOS does not help me do that; I am only allowed to run Platform A on Platform A.

So you mean you gotta tinker/hack?

I think we'd just like to have it labelled "for Mac Only right now"

How about linux users?

You’ve got to accept the fact they want to collect feedback from other users first and not you.

From some users first, even if that doesn't include you

No, specifically him. I’ve heard talk. I dunno what he did but he should apologize already.

Extremely featureful debuggers such as this one tend to require a great deal of code that is hardware-specific, in addition to being OS-specific. I assume MacOS was targeted first because it's the platform with the greatest degree of hardware uniformity. I fully expect Linux support to materialize someday, but with the caveat that I expect it will only (officially) work with the most popular hardware.

That's right. The only way to have a performant recording is to capture the browser's OS system calls in the recording. This unfortunately makes the feature quite OS specific.

https://searchfox.org/mozilla-central/source/toolkit/recordr...

Replay is currently in the user-research validation phase. We care about cross platform support and will prioritize it when we are ready to commit to the feature.

One would expect an organization dedicated to freedom to prioritize Linux support.

Mozilla has implemented DRM support in Firefox. I think Mozilla is more concerned with reducing dependence on nonfree software than supporting free software.

Just to clarify, I don't fault Mozilla for having that attitude, but that doesn't mean I prefer it. I would prefer that they prioritize FOSS platforms like Linux and \*BSD, as well as getting Firefox on platforms like Plasma Mobile, PostmarketOS, and other GNU/Linux-based mobile operating systems. Developer adoption is a necessary (but probably not sufficient) precondition for general adoption, which is why developing for these platforms is important even though they are new/unpopular.

Is there some technical reason it's only for os x? I'm not really upset they targeted Macs first but I am a bit curious why they felt a need to.

They mention it here[0]:

"Almost all implementation work so far has been on macOS. Windows port work is underway, but is not yet working. The difficulties are in figuring out the set of system library APIs to intercept, in getting the memory management and dirty memory parts of the rewind infrastructure to work, and in handling the different graphics and IPC pathways on different platforms."

[0]: https://developer.mozilla.org/en-US/docs/Mozilla/Projects/We...

Firefox is a native app that is ported between OSes. It doesn't run on a VM.

I don’t want to go all “you darn kids” so I won’t. But the pervasiveness of web technology I think has made the majority of us forget why it’s pervasive. Cross platform can be really fucking hard, especially if you don’t respect the challenges and end up down a blind alley.

One of my favorite books starting out was the Stevens book about Unix. It only covers the differences in system call availability and behavior across Unix OSes. It doesn’t even touch graphics. It’s a big fat book just covering file, network, processes, and memory operations. No Mac, no Microsoft, just Unix.

https://en.m.wikipedia.org/wiki/Advanced_Programming_in_the_...

Small user base to test?

Actually probably Mozilla’s largest user base

Why 'probably'? According to the stats I could find [1], Firefox has around 5% of Mac users, and around 9% of Windows users. Windows is Firefox's biggest platform, both in absolute terms and as a fraction of that platform's users.

On Linux, Firefox has a bigger percentage (>30%), but (desktop) Linux is much less popular than macOS so in absolute terms they have the fewest users there.

[1]: https://netmarketshare.com/

Mozilla’s Firefox Hardware Report has the latest desktop OS share across all Firefox channels:

  51% Windows 10
  27% Windows 7
   6% Windows 8
   6% macOS
  11% Other (Linux, BSDs, etc)

https://data.firefox.com/dashboard/hardware

I think the Firefox Nightly, Developer Edition, and Beta channels have a slightly higher share of macOS and Linux users, but not much. There are a lot of Windows users out there; you just don't see them at JS conferences. :)

The plan is to do user testing on mac and if it is validated roll it out.

Replay requires a ton of difficult platform-level investment to get right and we're still actively finding bugs in the real world.

After it is validated, it will be easier to add the appropriate platform level bindings in other OSs.

I'm really disappointed that Linux gets less attention from FOSS-supportive organizations like Mozilla. Desktop Linux adoption is a catch-22: people don't use it because it doesn't have as much software; however, it has less software because it's less popular.

Yep. It's noteworthy that over 10% of Mozilla's users are on Linux. [1] And presumably that only includes users who submit the hardware report. That's a huge portion for any cross-platform application. It's genuinely rather surprising that they don't give it more attention simply because it's a large portion of their user base, and because Linux users are more likely to submit bug reports and patches.

[1] https://news.ycombinator.com/item?id=21660399

I think there are good ideological reasons to support Linux, BSD, and other FOSS operating systems, not despite, but because of their unpopularity [0].

Edit: to clarify, I refer to operating systems that have a considerable amount of potential and existing development, not systems with like 2 users .

[0]: https://news.ycombinator.com/item?id=21660819

The statistic that matters for this tool is the distribution of developers, not the overall user base.

I can see some form of replay in firefox dev edition on windows

This project is advertised on its own domain (not a mozilla.org subdomain) and there's no header/footer/link to mozilla.org.

This makes me think that it's not a feature on the roadmap of firefox sponsored by Mozilla, but an experimentation/side project.

The fact that it's in Firefox Nightly seems to blow that hypothesis out of the water

I can't really tell whether this is an official Mozilla website (though it looks like one), but the feature is certainly an official one on the roadmap. See this earlier discussion: https://news.ycombinator.com/item?id=17624709