Crash when rendering a web page as PDF

[ariya]

This is a regression in master branch.

To reproduce it:

phantomjs examples/rasterize.js http://example.com example.pdf

PhantomJS will crash instead of producing the PDF file. Other formats (PNG, JPEG) don't have the problem.

Test on OS X.

[ariya]

An alternative self-contained test script:

var page = require('webpage').create();
page.open("about:blank", function() {
    page.render("test.pdf");
    phantom.exit()
});

[vitallium]

Can't confirm on Windows.

[ariya]

@vitallium Good to know! Hopefully this is not a cross-platform bug.
Let me check on Linux...

[vitallium]

PhantomJS crashes due to a null pointer here: https://github.com/ariya/phantomjs/blob/master/src/qt/qtbase/src/plugins/printsupport/cocoa/main.cpp#L66
We have implemented our platform plugin, but we didn't implemented createPlatformPrinterSupport method (it's marked as virtual in QPlatformIntegration).
/cc @milianw

[ariya]

I concur, the stack trace looks like this:

#0  0x000000010109d168 in QCocoaPrinterSupportPlugin::create ()
#1  0x00000001010aa8c8 in QPlatformPrinterSupportPlugin::get ()
#2  0x00000001010a1853 in QPrinterPrivate::initEngines ()
#3  0x00000001010a1ee2 in QPrinter::QPrinter ()
#4  0x00000001000154f8 in WebPage::renderPdf ()
#5  0x0000000100014cdc in WebPage::render ()
#6  0x0000000100064cd8 in WebPage::qt_static_metacall ()
#7  0x0000000100065fef in WebPage::qt_metacall ()
#8  0x00000001000e13ab in JSC::Bindings::QtRuntimeMethod::call ()
#9  0x0000000100d64a72 in JSC::JSCallbackFunction::call ()

[ariya]

OTOH, there is also a closely related upstream bug:

https://bugreports.qt-project.org/browse/QTBUG-33109.

Particularly interesting is that it seems this is general Qt on OS X QPlatformPrinterSupportPlugin problem in any static build.

[ariya]

I found a quick workaround. We simply need to implement PhantomIntegration::nativeInterface() that returns a dummy QPlatformNativeInterface instance (for now, it could be useful to extend this in the future). This will prevent QPlatformPrinterSupportPlugin::get() from crashing since it will not bother to load the Cocoa printer plugin (affected by the above upstream bug).

[kfix]

this commit fixed rasterize.js for me on 10.9 via Homebrew install --HEAD. thanks!