27169 2009-07-10 18:12:10 -0700 typing "document.__proto__" in inspector throws exception 2011-05-03 01:54:04 -0700 1 1 1 Unclassified WebKit Web Inspector (Deprecated) 528+ (Nightly build) PC OS X 10.5 RESOLVED FIXED P2 Normal --- 60014 1 eric webkit-unassigned abarth joepeck keishi timothy oldest_to_newest 131035 0 eric 2009-07-10 18:12:10 -0700 typing "document.__proto__" in inspector throws exception > document.__proto__ file:///Users/eseidel/Projects/build/Debug/WebCore.framework/Resources/inspector/utilities.js:843TypeError: Result of expression 'this.nodeName' [undefined] is not an object. 134044 1 joepeck 2009-07-22 23:48:47 -0700 After some digging it appears this is a rather weird edge case that can be reduced to this: > typeof document.__proto__ object > document.__proto__ instanceof window.Node true > document.__proto__.nodeName undefined > document.__proto__.nodeType undefined So when the formatter actually gets down to formating as a node, jumps into utilities.js's nodeTitleInfo(), does a switch on obj.nodeType (undefined) which hits the default case and tries obj.nodeName and throws the error. The Javascript workaround that I feel is the most responsible would be to treat "document.__proto__" as the type it returns via "typeof", which is "object", instead of "node". To be more general, if something is an "instanceof Node" then to really be sure its a node it should have a "nodeType" property. Otherwise its lieing! Maybe the solution is to change something in the Document C++ implementation so document.__proto__ instanceof "Node" returns false instead of true. 134045 2 33317 joepeck 2009-07-22 23:53:16 -0700 Created attachment 33317 Javascript Workaround This would be the javascript workaround. I looked into what Firefox does and they don't report document.__proto__ as an instanceof Node! So maybe that would be the better route. WebKit via Web Inspector: > document.__proto__ instanceof window.Node true Firefox via Firebug: > document.__proto__ instanceof window.Node false 134081 3 keishi 2009-07-23 04:54:27 -0700 (In reply to comment #2) > This would be the javascript workaround. I looked into what Firefox does and > they don't report document.__proto__ as an instanceof Node! So maybe that > would be the better route. Opera returns false too. But I can't figure out why. From my understanding, the implementation of FOO instanceof BAR should be something like this function instanceof(FOO, BAR) { var o = FOO; while (o = o.__proto__) { if (o === BAR.prototype) return true; } return false; } And I think this is written in JSObject::hasInstance which implements [[hasInstance]] from the spec. WebCore's prototype chain looks like this document.__proto__ = HTMLDocumentPrototype document.__proto__. __proto__ = DocumentPrototype document.__proto__. __proto__. __proto__ = NodePrototype document.__proto__. __proto__. __proto__.__proto__ = Object And (Node.prototype === document.__proto__. __proto__. __proto__) is true So (document.__proto__ instanceof window.Node) returns true. In Firefox (Node.prototype === document.__proto__. __proto__. __proto__) is also true so I don't understand why Firefox is returning false for (document.__proto__ instanceof window.Node). Which is correct? 134169 4 timothy 2009-07-23 11:37:42 -0700 obj.nodeType === undefined would be best written as: typeof obj.nodeType === "undefined" 134172 5 eric 2009-07-23 11:40:32 -0700 Did we decide there was a real bug here in either WebKit or Firefox? If so, we should file it... 134178 6 joepeck 2009-07-23 11:49:42 -0700 (In reply to comment #5) > Did we decide there was a real bug here in either WebKit or Firefox? If so, we > should file it... Filed. https://bugs.webkit.org/show_bug.cgi?id=27611 134468 7 abarth 2009-07-24 02:14:53 -0700 Committing to http://svn.webkit.org/repository/webkit/trunk ... M WebCore/ChangeLog M WebCore/inspector/front-end/utilities.js Committed r46345 M WebCore/ChangeLog M WebCore/inspector/front-end/utilities.js r46345 = 1203ffee2d3ca9a82f4ecd7eecf5061b5a6091e0 (trunk) No changes between current HEAD and refs/remotes/trunk Resetting to the latest refs/remotes/trunk http://trac.webkit.org/changeset/46345 33317 2009-07-22 23:53:16 -0700 2009-07-23 11:27:24 -0700 Javascript Workaround patch.patch text/plain 1036 joepeck ZGlmZiAtLWdpdCBhL1dlYkNvcmUvQ2hhbmdlTG9nIGIvV2ViQ29yZS9DaGFuZ2VMb2cKaW5kZXgg ZmMzODY5Ni4uZWM1M2RhYSAxMDA2NDQKLS0tIGEvV2ViQ29yZS9DaGFuZ2VMb2cKKysrIGIvV2Vi Q29yZS9DaGFuZ2VMb2cKQEAgLTEsMyArMSwxMyBAQAorMjAwOS0wNy0yMiAgSm9zZXBoIFBlY29y YXJvICA8am9lcGVjazAyQGdtYWlsLmNvbT4KKworICAgICAgICBSZXZpZXdlZCBieSBOT0JPRFkg KE9PUFMhKS4KKworICAgICAgICB0eXBpbmcgImRvY3VtZW50Ll9fcHJvdG9fXyIgaW4gaW5zcGVj dG9yIHRocm93cyBleGNlcHRpb24KKyAgICAgICAgaHR0cHM6Ly9idWdzLndlYmtpdC5vcmcvc2hv d19idWcuY2dpP2lkPTI3MTY5CisKKyAgICAgICAgKiBpbnNwZWN0b3IvZnJvbnQtZW5kL3V0aWxp dGllcy5qczoKKyAgICAgICAgKE9iamVjdC50eXBlKToKKwogMjAwOS0wNy0yMiAgUGF1bCBHb2Rh dmFyaSAgPHBhdWxAY2hyb21pdW0ub3JnPgogCiAgICAgICAgIFJldmlld2VkIGJ5IERhcmluIEZp c2hlci4KZGlmZiAtLWdpdCBhL1dlYkNvcmUvaW5zcGVjdG9yL2Zyb250LWVuZC91dGlsaXRpZXMu anMgYi9XZWJDb3JlL2luc3BlY3Rvci9mcm9udC1lbmQvdXRpbGl0aWVzLmpzCmluZGV4IDhmYjUw ZTIuLjUzZjU5OTUgMTAwNjQ0Ci0tLSBhL1dlYkNvcmUvaW5zcGVjdG9yL2Zyb250LWVuZC91dGls aXRpZXMuanMKKysrIGIvV2ViQ29yZS9pbnNwZWN0b3IvZnJvbnQtZW5kL3V0aWxpdGllcy5qcwpA QCAtMzgsNyArMzgsNyBAQCBPYmplY3QudHlwZSA9IGZ1bmN0aW9uKG9iaiwgd2luKQogICAgIHdp biA9IHdpbiB8fCB3aW5kb3c7CiAKICAgICBpZiAob2JqIGluc3RhbmNlb2Ygd2luLk5vZGUpCi0g ICAgICAgIHJldHVybiAibm9kZSI7CisgICAgICAgIHJldHVybiAob2JqLm5vZGVUeXBlID09PSB1 bmRlZmluZWQgPyB0eXBlIDogIm5vZGUiKTsKICAgICBpZiAob2JqIGluc3RhbmNlb2Ygd2luLlN0 cmluZykKICAgICAgICAgcmV0dXJuICJzdHJpbmciOwogICAgIGlmIChvYmogaW5zdGFuY2VvZiB3 aW4uQXJyYXkpCg==