Bug 9815 – JavaScript TypeError loading Dean Edwards' JS compressor/obfuscator

• Component: JavaScriptCore
• Status: RESOLVED FIXED

[David Kilzer (:ddkilzer)]

I got a type error when loading Dean Edwards' JavaScript Compressor/Obfuscator (see URL).  This error needs to be reduced.

[22954] http://dean.edwards.name/packer/packer-p.js line 1: TypeError: Value undefined (result of expression c.valueOf.prototype.specialize) is not object.

Using Safari 2.0.4 (419.3) with locally-built WebKit r15267 with a WIP patch for Bug 9179 on Mac OS X 10.4.7 (8J135/PowerPC).

Created attachment 10808 [details]
JS snippet demonstrating js bug

Looks to be problem with creating new from "reference"? "new this.valueOf" causes new object in Firefox but not Safari.
Reduced code from Dean Edwards ie7.js, which looks to use the same OO routines (the packer is obfuscated).

[David Kilzer (:ddkilzer)]

Created attachment 12291 [details]
Test case

Wrapped Attachment 10808 [details] in <script></script> tags.

[David Kilzer (:ddkilzer)]

(In reply to comment #2)
> Created an attachment (id=12291) [edit]
> Test case
> 
> Wrapped Attachment 10808 [details] [edit] in <script></script> tags.

Incorrect behavior prints "undefined" in the alert.

Correct behavior prints "function() { }" (on multiple lines) in the alert.

[David Kilzer (:ddkilzer)]

It appears that assigning new Function() to a variable does not set it's prototype, while assigning an anonymous function does.  Thus if you change this line:

  ICommon.valueOf = new Function("return this");

to this:

  ICommon.valueOf = function(){ return this; };

the test case will work.

[David Kilzer (:ddkilzer)]

This bug is in JavaScriptCore, and exists in shipping Safari 2.0.4 (419.3) on Mac OS X 10.4.8 (8N1037).

I also have a patch to fix it.

[David Kilzer (:ddkilzer)]

Created attachment 12727 [details]
Patch v1

Proposed fix.

[David Kilzer (:ddkilzer)]

(In reply to comment #6)
> Created an attachment (id=12727) [edit]
> Patch v1
> Proposed fix.

Note that all JavaScriptCore tests and all layout tests pass with this change.

[Darin Adler]

Comment on attachment 12727 [details]
Patch v1

r=me

[David Kilzer (:ddkilzer)]

Committed revision 19203.