On the KonqFrame::attach[Internal]() crash (Analysis, #58480 and others)..

[Maks Orlovich]

Hi..

Thanks largely to great investigative work by Malte S. Stretz, I think I 
understand one of frequently filed Konq crashers (at least 8x); as I can't 
fix it myself, though, I guess I'll post it here. 

The bt looks basically like this (occasionally the first entry may be cut 
off):
 #6 0x4128be47 in KonqFrame::attachInternal () from /opt/kde3/lib/konqueror.so 
 #7 0x4128bd81 in KonqFrame::attach () from /opt/kde3/lib/konqueror.so 
 #8 0x4127e445 in KonqView::switchView () from /opt/kde3/lib/konqueror.so 
 #9 0x4127d868 in KonqView::KonqView () from /opt/kde3/lib/konqueror.so 
 #10 0x412859f6 in KonqViewManager::setupView () from 
/opt/kde3/lib/konqueror.so 
 #11 0x41281e11 in KonqViewManager::Initialize () 
 from /opt/kde3/lib/konqueror.so 
 #12 0x41262a3e in KonqMainWindow::openView () from /opt/kde3/lib/konqueror.so 
 #13 0x4127cbb4 in KonqRun::foundMimeType () from /opt/kde3/lib/konqueror.so 
 #14 0x4003c481 in KParts::BrowserRun::slotBrowserMimetype () 
 from /opt/kde3/lib/libkparts.so.2 

Reproduction instructions:
Configure Konqueror to not open a part in the web browsing profile
Run konqueror --profile webbrowsing
Open a website that sends a nonsense mimetype -- #58480 gives 
msquadrat.de/env.sh as an example.
<crash>

Analysis:
When running w/o a part, the following code in KonqMainWindow::openView gets 
triggered: 

        // Create a new view
        // Initialize always uses force auto-embed even if user setting is 
"separate viewer",
        // since this window has no view yet - we don't want to keep an empty 
mainwindow.
        // This can happen with e.g. application/pdf from a target="_blank" 
link, or window.open.
        childView = m_pViewManager->Initialize( serviceType, serviceName );

KonqViwManager::Initialize calls createView to get a factory, but that fails, 
as the mimetype is not handled by anything 
(debug output: 
kio (KMimeType): WARNING: KServiceType::offers : servicetype text/x-sh not 
found
kio (KMimeType): WARNING: KServiceType::offers : servicetype text/x-sh not 
found
konqueror: WARNING: KonqFactory::createView : no factory), 

so an empty/null factory is returned.

Then setupView is called to create a part, which then passes the null factory 
through the KonqView ctor, into KonqView::switchView, and finally into 
KonqFrame::attach(). There, we do this:
m_pPart = factory.create( this, "view widget", 0, "" );

And proceed on to attachInternal which happily does stuff like
m_pLayout->addWidget( m_pPart->widget(), 1 ); where m_pPart is null, 
thus blowing up.

Obviously, this should be interrupted someplace along the way, but I
don't know where the right spot is. I am willing to do the legwork 
if someone just wants to direct me on fixing this.

Thanks,
Maks, 'Looking-through-Bugzilla Eagle'