143836 2015-04-16 11:55:21 -0700 Incorrect behavior when patching window.setTimeout 2015-04-20 11:53:26 -0700 1 1 1 Unclassified WebKit JavaScriptCore 528+ (Nightly build) Unspecified Unspecified NEW P2 Normal --- 1 mmanela webkit-unassigned ap ggaren sean zackw oldest_to_newest 1086002 0 250935 mmanela 2015-04-16 11:55:21 -0700 Created attachment 250935 File which demonstrates the issue This is a demonstration of a really strange issue in Webkit (and PhantomJS which uses Webkit). The issue involves what happens when you monkey patch the window.setTimeout method in Javascript. The issue was discovered when debugging test failures that were using sinonJS (which monkey patches setTimeout). I worked through that issue and distilled the minimum repro out of it. I validated this issue does not occur in Chrome 41, Firefox 36 and IE 11. As far as I can tell it only repros in Webkit based browsers (like Phantomjs). Short Repro 1: Define a method (check) which references window.setTimeout 2: Call this method two times, then patch setTimeout to be a custom method and then call check again. CODE: function check() { console.log("window.setTimeout = " + window.setTimeout); } check(); check(); window.setTimeout = function() { console.log ("Patched"); } check(); OUTPUT: window.setTimeout = function setTimeout() { [native code] } window.setTimeout = function setTimeout() { [native code] } window.setTimeout = function setTimeout() { [native code] } 3: Then call to check the third time will not output the contents of the monkey patched function. It will still contain the native one. THe odd thing is if you call the check() method only once (or not at all) before your patched setTimeout then it will output the expected value. For example: CODE: function check() { console.log("window.setTimeout = " + window.setTimeout); } check(); window.setTimeout = function() { console.log ("Patched"); } check(); OUTPUT: window.setTimeout = function setTimeout() { [native code] } window.setTimeout = function () { console.log("PATCHED"); } 1086183 1 ap 2015-04-16 17:21:37 -0700 I cannot reproduce this in Safari 7.1.5, nor in a current WebKit build. 1086310 2 mmanela 2015-04-17 06:46:51 -0700 Thanks for the comment. I reproed this on windows using PhantomJS which is build on top of QtWebKit. I checked what version of Webkit that is using and it said the following in QtWebKit: """ This is a snapshot of WebKit. It is based on the upstream trunk subversion revision 153112 You can browse the base of this snapshot at http://trac.webkit.org/browser/trunk?rev=153112 Additional patches may have been applied on top and files not required by the Qt port may have been removed. """ 1086700 3 mmanela 2015-04-19 17:04:51 -0700 Also, I hit this issue on Windows. Could there be an OS specific bug? 1086827 4 zackw 2015-04-20 11:15:56 -0700 Over at https://github.com/ariya/phantomjs/issues/13158 we are able to reproduce the problem in both Midori and PhantomJS, but only on Windows. 250935 2015-04-16 11:55:21 -0700 2015-04-16 11:55:21 -0700 File which demonstrates the issue test[1].html text/html 1492 mmanela CjwhRE9DVFlQRSBodG1sPgo8aHRtbD4KPGhlYWQ+CiAgICA8bWV0YSBjaGFyc2V0PSJ1dGYtOCIg Lz4KICAgIDx0aXRsZT5TZXRUaW1lb3V0IFBoYW50b20gUmVwcm88L3RpdGxlPgoKPHNjcmlwdCB0 eXBlPSJ0ZXh0L2phdmFzY3JpcHQiPgoJCgovLyBUaGlzIG1ldGhvZCBpcyBjYWxsZWQgMyB0aW1l cwpmdW5jdGlvbiBjaGVjazEoKSB7CiAgICBjb25zb2xlLmxvZygiY2hlY2sxOiB3aW5kb3cuc2V0 VGltZW91dCA9ICIgKyB3aW5kb3cuc2V0VGltZW91dCk7Cn0KCgoKLy8gVGhpcyBtZXRob2QgaXMg Y2FsbGVkIDIgdGltZXMKZnVuY3Rpb24gY2hlY2syKCkgewogICAgY29uc29sZS5sb2coImNoZWNr Mjogd2luZG93LnNldFRpbWVvdXQgPSAiICsgd2luZG93LnNldFRpbWVvdXQpOwp9CgoKLy8gVGhp cyBtZXRob2Qgd2lsbCBiZSBjYWxsZWQgMSB0aW1lCmZ1bmN0aW9uIGNoZWNrMygpIHsKICAgIGNv bnNvbGUubG9nKCJjaGVjazM6IHdpbmRvdy5zZXRUaW1lb3V0ID0gIiArIHdpbmRvdy5zZXRUaW1l b3V0KTsKfQoKCmNvbnNvbGUubG9nKCIxLiBDYWxsIG1ldGhvZCBjaGVjazEgd2hpY2ggb3V0cHV0 cyBjb250ZW50cyBvZiB3aW5kb3cuc2V0VGltZW91dCIpOwpjaGVjazEoKTsKCgpjb25zb2xlLmxv ZygiMi4gQ2FsbCBtZXRob2RzIGNoZWNrMSBhbmQgY2hlY2syIHdoaWNoIGJvdGggb3V0cHV0IGNv bnRlbnRzIG9mIHdpbmRvdy5zZXRUaW1lb3V0Iik7CmNoZWNrMSgpOwpjaGVjazIoKTsKCgoKCmNv bnNvbGUubG9nKCIzLiBNb25la3ktcGF0Y2ggdGhlIGNvbnRlbnRzIG9mIHdpbmRvdy5zZXRUaW1l b3V0IHdpdGggYSBkdW1teSBtZXRob2Qgd2hpY2gganVzdCBvdXRwdXRzIHRoZSB3b3JkcyBQQVRD SEVEIik7Cgp2YXIgb2xkVGltZW91dCA9IHdpbmRvdy5zZXRUaW1lb3V0OwoKd2luZG93LnNldFRp bWVvdXQgPSBmdW5jdGlvbigpIHsgY29uc29sZS5sb2coIlBBVENIRUQiKTsgfQoKCgpjb25zb2xl LmxvZygiNC4gQ2FsbCBtZXRob2RzIGNoZWNrMSwgY2hlY2syIGFuZCBjaGVjazMgd2hpY2ggb3V0 cHV0cyBjb250ZW50cyBvZiB3aW5kb3cuc2V0VGltZW91dC4iKTsKCi8vIFByaW50cyBvdXQgc3lz dGVtIHNldFRpbWVvdXQKY2hlY2sxKCk7CgovLyBQcmludHMgQ3VzdG9tIHNldFRpbWVvdXQKY2hl Y2syKCk7CgovLyBQcmludHMgQ3VzdG9tIHNldFRpbWVvdXQKY2hlY2szKCk7CgoKd2luZG93LnNl dFRpbWVvdXQgPSBvbGRUaW1lb3V0OwoKCiBjb25zb2xlLmxvZygiNS4gTm90ZSB0aGF0IGNoZWNr MyAod2hpY2ggaXMgY2FsbGVkIG9uY2UgaW4gdGhpcyBmaWxlKSBhbmQgY2hlY2syICh3aGljaCBp cyBjYWxsZWQgdHdpY2UpIGJvdGggcHJpbnQgb3V0IHRoZSBleHBlY3RlZCBwYXRjaGVkIHNldFRp bWVvdXQgbWV0aG9kLiBIb3dldmVyLCBjaGVjazEgKHdoaWNoIGlzIGNhbGxlZCB0aHJlZSB0aW1l cykgZG9lcyBub3QuICIpOwoKPC9zY3JpcHQ+Cgo8L2hlYWQ+Cgo8Ym9keT4KICAgIAo8L2JvZHk+ CjwvaHRtbD4KCg==