14611 2007-07-13 12:01:47 -0700 Incorrect JavaScript const declaration behaviour 2012-03-07 00:31:30 -0800 1 1 1 Unclassified WebKit JavaScriptCore 523.x (Safari 3) Mac OS X 10.4 RESOLVED DUPLICATE 31813 P2 Normal --- 1 zwarich webkit-unassigned barraclough bugmail darin dstorey feng webmaster oldest_to_newest 4878 0 zwarich 2007-07-13 12:01:47 -0700 When I was fixing the patch for bug 13517 so that it would past fast/js/const, I realized that const is currently handled incorrectly. A variable that is declared with either a var declaration or a const declaration can be redeclared (and given a new value) with const, which is against <http://developer.mozilla.org/en/docs/Core_JavaScript_1.5_Reference:Statements:const>. 4874 1 15503 zwarich 2007-07-13 12:04:42 -0700 Created attachment 15503 Test case Here is a test case. I have a pretty good idea of a patch, but it depends on the fix for bug 13517, so I will wait until that is resolved. 4745 2 ddkilzer 2007-07-14 16:01:20 -0700 Confirmed with a local debug build of WebKit r24285 with Safari 3.0 (522.12) on Mac OS X 10.4.10 (8R218). Opera 9.21.3678 fails as well. 81218 3 zwarich 2008-05-22 11:10:37 -0700 *** Bug 19194 has been marked as a duplicate of this bug. *** 95696 4 zwarich 2008-10-16 19:59:26 -0700 *** Bug 21700 has been marked as a duplicate of this bug. *** 118850 5 bugmail 2009-04-25 16:07:53 -0700 consts can also be deleted. Which is against Mozilla's spec. Attempting to delete a const should return false and fail (not throwing any errors though). 118851 6 29789 bugmail 2009-04-25 16:09:32 -0700 Created attachment 29789 testcase that also tests deleting a const 118853 7 zwarich 2009-04-25 16:17:41 -0700 Oh yeah, so much is wrong with our implementation of 'const'. In practice, it doesn't matter at all, because nothing depends on the correct behaviour. We should fix it some day, but I don't think it is a priority right now given the other bugs that are open. If someone knows of a site that this breaks, mention it here and I'll try to fix it. 118855 8 bugmail 2009-04-25 16:37:02 -0700 (In reply to comment #7) IMO, it's pretty important if you want to make library that, if a site scumbs to an XSS flaw, the library reports a bug on itself on a page. For example: const reportXSSFlawedPage = function() { do_some_stuff_with(location.href) }; In Firefox, the website will report an error to the admin so he can get the library fixed ASAP. In WebKit, the XSS attack knows about the "reportXSSFlawedPage" function, and overwrites it. The admin doesn't find out about the XSS flaw until quite a few users have been affected. 140729 9 bugmail 2009-08-17 09:31:25 -0700 *** Bug 21701 has been marked as a duplicate of this bug. *** 572642 10 barraclough 2012-03-07 00:31:30 -0800 Our const behavior currently doesn't respect any spec, and therefore can do whatever it wants. :-) Our intention is to fix this by replacing our current implementation with one that implements Harmony block scoped const; this bug should be subsumed as a part of that change. *** This bug has been marked as a duplicate of bug 31813 *** 15503 2007-07-13 12:04:42 -0700 2007-07-13 12:04:42 -0700 Test case consttest.html text/html 107 zwarich PHNjcmlwdD4KdmFyIHggPSAiIjsKY29uc3QgeCA9ICJ3cm9uZyEiOwoKYWxlcnQoeCk7Cgpjb25z dCB5ID0gIiI7CmNvbnN0IHkgPSAid3JvbmchIjsKCmFsZXJ0KHkpOwo8L3NjcmlwdD4= 29789 2009-04-25 16:09:32 -0700 2009-04-25 16:09:32 -0700 testcase that also tests deleting a const const.html text/html 1138 bugmail 77u/PCFkb2N0eXBlIGh0bWw+CjxodG1sPgo8aGVhZD4KPG1ldGEgY2hhcnNldD0idXRmLTgiLz4K PHRpdGxlPmNvbnN0IFRlc3RjYXNlPC90aXRsZT4KPHNjcmlwdCB0eXBlPSJ0ZXh0L2phdmFzY3Jp cHQiIHNyYz0iL3hjY2Vzc29ycy9sYXRlc3QveGNjZXNzb3JzLm1pbi5qcyI+PC9zY3JpcHQ+Cjwv aGVhZD4KPGJvZHk+CjxoMT48Y29kZT5jb25zdDwvY29kZT4gVGVzdGNhc2U8L2gxPgo8c2NyaXB0 IHR5cGU9InRleHQvamF2YXNjcmlwdCIgZGVmZXI9InRydWUiPgovLzwhW0NEQVRBWwoKdmFyIHJl c3VsdHMgPSAgIiI7Cgpjb25zdCBmb28gPSA1Owpjb25zdCBiYXIgPSA2Owpjb25zdCBiYXogPSA3 Owpjb25zdCBmb29iYXIgPSA4OwoKCnRyeSB7IGV2YWwoInZhciBmb28gPSA0IikgfQpjYXRjaCAo ZSkge30KCnJlc3VsdHMgKz0gImNvbnN0IGZvbyAgPT0gIitmb287CnJlc3VsdHMgKz0gIlxuZm9v IHNob3VsZCA9PSA1IjsKCnRyeSB7IGV2YWwoImNvbnN0IGJhciA9IDUiKSB9CmNhdGNoIChlKSB7 fQoKcmVzdWx0cyArPSAiXG5cbmNvbnN0IGJhciAgPT0gIitiYXI7CnJlc3VsdHMgKz0gIlxuZm9v IHNob3VsZCA9PSA2IjsKCgp0cnkgeyB2YXIgYmF6X2RlbGV0ZWQgPSBkZWxldGUgYmF6OyB9CmNh dGNoIChlKSB7fQoKcmVzdWx0cyArPSAiXG5cbmNvbnN0IGJheiBjYW4gYmUgZGVsZXRlZCAgPT0g IitiYXpfZGVsZXRlZDsKcmVzdWx0cyArPSAiXG5iYXogY2FuIGJlIGRlbGV0ZWQgc2hvdWxkID09 IGZhbHNlIjsKcmVzdWx0cyArPSAiXG50eXBlb2YgY29uc3QgYmF6ICA9PSAiK3R5cGVvZiBiYXo7 CnJlc3VsdHMgKz0gIlxudHlwZW9kIGJheiBzaG91bGQgPT0gbnVtYmVyIjsKCnRyeSB7IGZvb2Jh ciA9IDcgfQpjYXRjaCAoZSkge30KCnJlc3VsdHMgKz0gIlxuXG5jb25zdCBmb29iYXIgID09ICIr Zm9vYmFyOwpyZXN1bHRzICs9ICJcbmZvb2JhciBzaG91bGQgPT0gOCI7CgoKdmFyIGNvbnRhaW5l ciA9IGRvY3VtZW50LmNyZWF0ZUVsZW1lbnQoInByZSIpOwoKY29udGFpbmVyLmFwcGVuZENoaWxk KGRvY3VtZW50LmNyZWF0ZVRleHROb2RlKHJlc3VsdHMpKQoKZG9jdW1lbnQuZG9jdW1lbnRFbGVt ZW50LmFwcGVuZENoaWxkKGNvbnRhaW5lcik7Cgo8L3NjcmlwdD4KPC9ib2R5Pgo8L2h0bWw+Cg==