[webkit-dev] EventTarget Changes Causes Safari Launch Problems

Alex Milowski alex at milowski.org
Thu Feb 10 13:56:19 PST 2011

On Wed, Feb 9, 2011 at 8:03 PM, Alex Milowski <alex at milowski.org> wrote:
> In a recent set of "experiments" in changes to XML processing, I added
> a new EventTarget class called XMLReader.  As such, I had to add a
> "toXMLReader()" method to the EventTarget class.  Previously, this has
> worked well but now, after updating this code to the latest trunk, I
> have a problem launching Safari (it crashes right at startup without
> even showing a window).  It is unclear to me why it would have worked
> before but now does not.
> I've narrowed my troubles down to what I think is a virtual table
> change relating to the class structure although I really haven't
> proven that.  If I hack my way around the need for the toXMLReader()
> method on EventTarget, doing some very unsavory things, the latest
> trunk with my changes and the latest version of Safari work fine.
> Any ideas why, within the last month, this would all change?  Was I
> just lucky before?

Grumble.  This is a complete mystery but I think something in the
build is trying to be too smart.  It didn't make sense that code that
I built (WebKit) would have a wrong virtual table for other code that
I just build (WebCore).  After leaving out my final change to the
EventTarget class, I added in my method again, removed the build
directory, and rebuilt.   I can now launch safari.

In the last couple days, I have done the same process of deleting the
WebKitBuild directory, starting over with a clean build, and safari
crashes.  Is there something else that I should delete to make sure
everything is in sync?  Pre-compiled headers?  I think the WebKit code
built was out of sync with the WebCore changes I made but I can't see
why that would be when I removed the build directory and ran the
build-webkit script.  That should have built everything correctly
since I started from scratch.

Anyway, things are back to normal.  I'll put the paper and the patch
up somewhere nearer to when I present this at XML Prague in late

--Alex Milowski
"The excellence of grammar as a guide is proportional to the paucity of the
inflexions, i.e. to the degree of analysis effected by the language

Bertrand Russell in a footnote of Principles of Mathematics

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