Bug 27419 - Storing a reference to WorkerContext.postMessage() and calling it later yields a TypeError
Summary: Storing a reference to WorkerContext.postMessage() and calling it later yield...
Alias: None
Product: WebKit
Classification: Unclassified
Component: WebCore JavaScript (show other bugs)
Version: 528+ (Nightly build)
Hardware: PC OS X 10.5
: P2 Normal
Assignee: Dmitry Titov
Depends on: 27420
  Show dependency treegraph
Reported: 2009-07-18 17:51 PDT by Andrew Wilson
Modified: 2009-07-24 12:56 PDT (History)
3 users (show)

See Also:

test case (1.01 KB, patch)
2009-07-20 10:50 PDT, Andrew Wilson
no flags Details | Formatted Diff | Diff
proposed patch (6.54 KB, patch)
2009-07-21 13:52 PDT, Andrew Wilson
abarth: review+
Details | Formatted Diff | Diff

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Description Andrew Wilson 2009-07-18 17:51:47 PDT
There are a number of functions defined at global scope in WorkerContext - for example, setTimeout() and postMessage() are both defined in the worker global context.

It's perfectly valid for worker code to do this:


However, if the worker code does this instead, it gets a TypeError:

var saved = postMessage;
Comment 1 Andrew Wilson 2009-07-18 17:58:36 PDT
The test case works in Chromium, so it's somewhere in the JSC bindings.
Comment 2 Andrew Wilson 2009-07-20 10:30:23 PDT
On a related note, the following line of code from Worker Context results in a TypeError also:

postMessage.call(null, "foobar");
Comment 3 Andrew Wilson 2009-07-20 10:50:44 PDT
Created attachment 33094 [details]
test case

test case that shows this problem (passes on FF/Chrome, fails on Safari 4)
Comment 4 Andrew Wilson 2009-07-21 13:52:48 PDT
Created attachment 33209 [details]
proposed patch

This is dependent on 27420 as it relies on the IsWorkerContext attribute added in that patch.
Comment 5 Adam Barth 2009-07-23 23:11:40 PDT
Comment on attachment 33209 [details]
proposed patch

Awesome.  Thanks for the patch.
Comment 6 Dmitry Titov 2009-07-24 11:01:13 PDT
assingning to me for landing
Comment 7 Dmitry Titov 2009-07-24 12:56:49 PDT
Landed: http://trac.webkit.org/changeset/46371