DataCloneError on IE11

[gideonthomas]

I get this when I try to run Brackets on IE11:

Not sure what's happening but it seems to be something wrong with postMessage (which I thought we fixed by using MessageChannel).

@humphd any ideas?

[humphd]

This appears to be an instance of us trying to use an object (probably a buffer) that has been transferred across a MessageChannel and isn't available on the sending side anymore. We really need to see this happen in a src/ build so we can get a better stack.

NOTE: you still use postMessage with MessageChannel but you do it over a port vs. over a window.

[gideonthomas]

Just to clarify, this only happens on Windows 8.1 IE 11. Works fine on WIndows 10 IE 11

[gideonthomas]

@humphd so it breaks here: https://github.com/mozilla/brackets/blob/master/src/bramble/ChannelUtils.js#L49 (I can't get any more info than DataCloneError).

[humphd]

I'm trying to reproduce now. I have a VM with Windows 8.1 and IE11 (11.0.9600.16384).

So far I can't hit it. After fixing #717, I see this:

When I run full Thimble, everything seems to work, except I don't see any files in the Filetree (no errors related to this):

If I manually add an HTML file, it works, and shows up. Not sure what this is all about. Something is silently failing and not writing files to the fs.

No DataCloneError though. Any more STR or info?

[gideonthomas]

@humphd can you try loading https://brackets-testing.herokuapp.com/src/hosted.html in your vm? That's where I get the error.

[humphd]

Works fine:

We must be running different versions somehow?

[humphd]

I wonder if you're hitting this: https://connect.microsoft.com/IE/feedback/details/783468/ie10-window-postmessage-throws-datacloneerror-for-transferrable-arraybuffers

That's exactly what we do. Why does it work for me, though?

[gideonthomas]

hmm that's also IE 10. This is what I see:

I've asked code.org to confirm and tell us what they see.

[humphd]

So I'm running with 11.0.9600.16384 and you have 11.0.9600.16663, so your'e ahead of me. Maybe they broke something in a later update?

[gideonthomas]

Not sure. I also noticed that you're using Edge's devtools. I wonder if it isn't showing the datacloneerror while IE11's devtools is.

[humphd]

Do you want to try a test? This code is basically testing to see if it's possible to use dataTransferrables. What if you do this:

try {
    port.postMessage({buffer: buffer}, [buffer]);
} catch(e) {
    port.postMessage({buffer: buffer});
}

[humphd]

I filed a bug in Thimble on the filetree being empty. It's possible that these are connected.

I think it's unlikely (but not impossible) that I'm hitting this DataCloneError and just not seeing it.

[gideonthomas]

Ran the test, it goes into the catch block and then breaks here: https://github.com/mozilla/brackets/blob/master/src/filesystem/impls/filer/RemoteFiler.js#L70

[humphd]

OK, try this please:

try {
    port.postMessage({buffer: buffer}, [buffer]);
} catch(e) {
    callback(null, false);
}