7693 2006-03-09 21:52:02 -0800 WebKit relies on unpredictable timing for onload events 2006-03-17 12:30:19 -0800 1 1 1 Unclassified WebKit WebKit Misc. 420+ Mac OS X 10.4 RESOLVED FIXED Regression P1 Normal --- 5122 5487 6560 1 pumpkingod webkit-unassigned ap mitz oldest_to_newest 35672 0 pumpkingod 2006-03-09 21:52:02 -0800 Yeah, I'm not too sure about it myself yet, but I've been struggling for hours with seemingly random test case regressions that shouldn't be caused by my patch, and this bug seems to be the cause. Basically, if you introduce a delay into DRT's code, and it doesn't like it, the RenderTree will be output before javascript requesting text only output can run, which will obviously make test cases fail. I've reproduced this on a clean source tree by simply loading DumpRenderTree up in a debugger, running it with LayoutTests/dom/html/level2/html/HTMLBodyElement07.html, and pausing execution at some point while it runs, and then resuming it. That causes it to consistently output the full render tree for me, even though that specific test case requests a text only output. I won't be able to submit my patch to 5122 until this is fixed :( 35675 1 pumpkingod 2006-03-09 22:02:38 -0800 In fact, it even happens when just running it in the debugger with no breakpoints or pauses. It seems pretty random 35676 2 ap 2006-03-09 22:14:30 -0800 Sounds like the same as this random failure I got from BuildBot yesterday: <http://build.webkit.org/results/post-commit-powerpc-mac-os-x/990/results.html>. 35678 3 6975 pumpkingod 2006-03-09 22:46:03 -0800 Created attachment 6975 A test case for the bug To reproduce the bug, try putting this in your WebKit folder, and type bash Bug.bash > results This is simultaneously running the same test 20 times to make sure it gets nice and slow, and outputting it to the results file. If you check the results when it's done, you'll find that several of the results give the full render tree of the unmodified (by the javascript onload event) page, and others show a text only representation of the modified page. 35693 4 pumpkingod 2006-03-10 01:01:59 -0800 It's apparently not specific to DumpRenderTree, but that's just where I ran into it. I'll look deeper into it tomorrow 35714 5 mitz 2006-03-10 05:09:02 -0800 The root cause for the undeterministic behavior is that <object> (and perhaps other) subframes are created and loaded by the render tree, triggered either by the layout timer or by event dispatch or by other mechanisms. Frame::checkCompleted(), which emits the load DOM event, waits for the subframes to load, but obviously only if they have already been created. This warrants a bug by itself, since it means that the document load event may arbitrarily be emitted before subframes have loaded. What's causing the problem here, though, is that in the case that the subframe gets created and its main resource fails to load, the order of calls in -[WebDataSource _receivedMainResourceError:complete:] is such that the WebFrame reports completion (which invokes DRT's waiting delegate and causes it to dump) before the WebCore Frame checks for completion (which fires the onload handler, calling dumpAsText, waitUntilDone etc. when it's too late). 35715 6 6986 mitz 2006-03-10 06:36:16 -0800 Created attachment 6986 Reduction This file reliably reproduces the bug. When you invoke DRT on it, the lines appear in the reverse order, since the dump is triggered before the load event. If you delete the <script></script> on the fifth line, the lines appear in the correct order, since the subframe loading isn't triggered. The order of the calls in -[WebDataSource _receivedMainResourceError:complete:] was changed in r10901 to fix <rdar://problem/3853672> (Malformed HTML using crashes Safari in NSFireTimer), so part of this bug is probably a regression. 36490 7 7096 mitz 2006-03-15 16:30:59 -0800 Created attachment 7096 Emit load events before notifying the WebFrame load delegate Retaining the bridge and checking the cancelled flag in -[WebLoader didFailWithError:] are sufficient to prevent the <rdar://problem/3853672> crash (or an assertion failure). The updated acid2 results should finally fix bug 5487. This patch obviously doesn't address the other issue I mentioned in comment #5. 36493 8 mitz 2006-03-15 17:01:52 -0800 I am pretty sure now (also based on the date bug 5487 was reported) that this is a regression from the fix for <rdar://problem/3853672>. 36494 9 darin 2006-03-15 17:08:18 -0800 (In reply to comment #5) > The root cause for the undeterministic behavior is that <object> (and perhaps > other) subframes are created and loaded by the render tree, triggered either by > the layout timer or by event dispatch or by other mechanisms. > > Frame::checkCompleted(), which emits the load DOM event, waits for the > subframes to load, but obviously only if they have already been created. This > warrants a bug by itself, since it means that the document load event may > arbitrarily be emitted before subframes have loaded. Either Maciej or Hyatt (can't remember which) mentioned to me the other day that we probably should be loading subframes based on the DOM tree, not the render tree. 36533 10 7096 darin 2006-03-16 01:00:22 -0800 Comment on attachment 7096 Emit load events before notifying the WebFrame load delegate OK. Seems like we can do this -- taking a risk sounds good. Shouldn't have braces around that return in WebLoader.m. r=me 36771 11 bdakin 2006-03-17 12:30:19 -0800 I comitted this patch 6975 2006-03-09 22:46:03 -0800 2006-03-09 22:46:03 -0800 A test case for the bug Bug.bash text/plain 171 pumpkingod IyEvYmluL2Jhc2gKClRFU1RTPTIwCgphPTAKCndoaWxlIFsgJGEgLWx0ICIkVEVTVFMiIF0KZG8K CWE9JCgoJGErMSkpCgoJLi9XZWJLaXRCdWlsZC9EZWJ1Zy9EdW1wUmVuZGVyVHJlZSBMYXlvdXRU ZXN0cy9kb20vaHRtbC9sZXZlbDIvaHRtbC9IVE1MQm9keUVsZW1lbnQwNy5odG1sICYKCmRvbmUK 6986 2006-03-10 06:36:16 -0800 2006-03-10 06:36:16 -0800 Reduction loadEvents.html text/html 249 mitz PHNjcmlwdD5sYXlvdXRUZXN0Q29udHJvbGxlci5kdW1wQXNUZXh0KCk8L3NjcmlwdD4KPEJPRFkg b25sb2FkPSJkZWJ1ZygnVGhpcyBzaG91bGQgYmUgdGhlIGZpcnN0IGxpbmUnKSI+Ci0tJmd0IFRo aXMgc2hvdWxkIGJlIHRoZSBzZWNvbmQgbGluZQogICAgPE9CSkVDVCBEQVRBPSJhRmlsZVRoYXRE b2VzTm90RXhpc3QuZ2lmIiBDT0RFVFlQRT0iaW1hZ2UvZ2lmIj48L09CSkVDVD4KICAgIDxzY3Jp cHQ+PC9zY3JpcHQ+CjwvQk9EWT4K 7096 2006-03-15 16:30:59 -0800 2006-03-16 01:00:22 -0800 Emit load events before 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