Hi, everyone. I've been tinkering around with Harmony's Proxy and WeakMap implementations, and I've run into a problem. A Jasmine test which works fine in Mozilla Firefox Aurora builds throws an exception in Google Chrome Dev builds, with the experimental JavaScript features enabled.
I really need some help in identifying whether the bug is in Aurora, Chrome, or in my own code. I wrote all of the JavaScript code in the project, and to my knowledge none of it is browser- or engine-specific; it should all conform to Harmony and ECMAScript standards unless I have a bug in my code. The concept I'm working on is using Proxy to create prototype objects for constructor functions, and using a membrane like Tom van Cutsem's to isolate private properties from public ones. Steps to reproduce are below. I have partially reduced my testcase so that other parts of my project are not run as part of the test, and no Makefile or other scripting commands are necessary. Terminal commands: hg clone --branch ProxyConstructorTest http://code.google.com/p/dimensionalmap test-proto-membrane cd test-proto-membrane/ hg update --rev 5992f4c09a38 Open V8-SpiderMonkey-test.html in Mozilla Firefox Aurora and in Google Chrome Dev 19. In FF Aurora, all tests pass. In GC Dev: TypeError: Object.getOwnPropertyDescriptor called on non-object at Function.getOwnPropertyDescriptor (native) at Object.getDesiredPropertyOwner (file:///home/ajvincent/repositories/test-proto-membrane/ProtoMembrane/Membrane.js:59:34) at Object.foo (file:///home/ajvincent/repositories/test-proto-membrane/ProtoMembrane/Membrane.js:82:31) at [object Object].<anonymous> (file:///home/ajvincent/repositories/test-proto-membrane/spec/ProtoMembrane.js:94:21) The function executing is in ProtoMembrane/Membrane.js: getDesiredPropertyOwner: function(originalThis, name) { var _thisObj = this.getPrivate(originalThis); if (_thisObj == originalThis) { while (_thisObj && !Object.getOwnPropertyDescriptor(Object.getPrototypeOf(_thisObj), name)) { _thisObj = Object.getPrototypeOf(_thisObj); } } return _thisObj; }, In Aurora, _thisObj != originalThis, so it just moves on. In GC Dev, _thisObj == originalThis, and on the second iteration of the while loop, Object.getPrototypeOf(_thisObj) is null. Object.getOwnPropertyDescriptor(null, "foo"); throws the TypeError. -- "The first step in confirming there is a bug in someone else's work is confirming there are no bugs in your own." -- Alexander J. Vincent, June 30, 2001
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