Bug 94581 – window.postMessage() / MessagePort.postMessage() throw wrong exception for invalid ports argument

• Component: WebCore Misc.
• Status: RESOLVED FIXED

[Chris Dumez]

1. According to the latest specification for window.postMessage() (http://www.w3.org/TR/html5/comms.html#dom-window-postmessage-2):
"Throws an INVALID_STATE_ERR if the ports array is not null and it contains either null entries or duplicate ports."

We currently throw a DATA_CLONE_ERR.

2. According to the latest specification for MessagePort.postMessage() (http://www.w3.org/TR/html5/comms.html#messageport):
"Throws an INVALID_STATE_ERR if the ports array is not null and it contains either null entries, duplicate ports, or the source or target port."

We currently throw a DATA_CLONE_ERR for those cases.

We should fix this to comply with the latest specification.

[Chris Dumez]

Created attachment 159652 [details]
Patch

[Chris Dumez]

Created attachment 159655 [details]
Patch

[Chris Dumez]

Created attachment 159656 [details]
Patch

[Kentaro Hara]

Comment on attachment 159656 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=159656&action=review

The change looks OK. I just want to confirm cross-browser compatibility before r+ing it.

> Source/WebCore/bindings/v8/V8Utilities.cpp:117
> +            if (ports.contains(port)) {
> +                setDOMException(INVALID_STATE_ERR, isolate);
> +                return false;
> +            }

This change is trying to throw exception for the code that had not thrown exception before. What are the behaviors of other browsers (IE, Firefox and Opera)?

[Chris Dumez]

Firefox does not seem to support MessageChannel / MessagePort at all:
https://bugzilla.mozilla.org/show_bug.cgi?id=677638
https://bugzilla.mozilla.org/show_bug.cgi?id=741618

[Kentaro Hara]

(In reply to comment #5)
> Firefox does not seem to support MessageChannel / MessagePort at all:
> https://bugzilla.mozilla.org/show_bug.cgi?id=677638
> https://bugzilla.mozilla.org/show_bug.cgi?id=741618

Thanks, how about Opera and IE?

[Chris Dumez]

On Opera, it throws a DATA_CLONE_ERR instead of an INVALID_STATE_ERR, but at least it throws:
PASS channel.port1.postMessage("duplicate port", [channel3.port1, channel3.port1]) threw exception DOMException: DATA_CLONE_ERR.

I'm not sure how I can check for IE.

[Kentaro Hara]

Comment on attachment 159656 [details]
Patch

I checked it on IE. IE doesn't implement MessageChannel.

- IE and Firefox don't implement MessageChannel.

- Given that Opera throws exceptions, it makes sense for WebKit to throw some exception.

- Although Opera throws DATA_CLONE_ERR, the spec requires to throw INVALID_STATE_ERR. Since people wouldn't much care about the exception type, it sounds reasonable to change WebKit to throw INVALID_STATE_ERR according to the spec.

Let me r+ for now. But let's wait for landing the patch for one day, as someone might have a concern.

[Chris Dumez]

Comment on attachment 159656 [details]
Patch

No one has raised any concerned and the EWS bots are all green. Setting cq flag. Could someone please commit?

[Kentaro Hara]

Comment on attachment 159656 [details]
Patch

OK, thanks for the patch.

[WebKit Review Bot]

Comment on attachment 159656 [details]
Patch

Clearing flags on attachment: 159656

Committed r126286: <http://trac.webkit.org/changeset/126286>

[WebKit Review Bot]

All reviewed patches have been landed.  Closing bug.