Bug 27419

Summary: Storing a reference to WorkerContext.postMessage() and calling it later yields a TypeError
Product: WebKit Reporter: Andrew Wilson <atwilson>
Component: WebCore JavaScriptAssignee: Dmitry Titov <dimich>
Severity: Normal CC: ap, dimich, sam
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: PC   
OS: OS X 10.5   
Bug Depends on: 27420    
Bug Blocks:    
Description Flags
test case
proposed patch abarth: review+

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