title: _WebSafeForwarder forwardInvocation crashes
body: <p>I'm getting quite a few errors which appear to be related to WebKit in my iOS project. To give some background, we use WebViews in our application for displaying news stories. These news stories often include links and when the user clicks on the links, we usually bring the user to Safari to read a full news article. Pretty standard stuff. Anyways, here's what the crash looks like:</p>
  
  <pre><code>0     libobjc.A.dylib                       0x31198f78 objc_msgSend + 15
  1     CoreFoundation                        0x313567e4 __invoking___ + 68
  2     CoreFoundation                        0x312b17b1 -[NSInvocation invoke] + 160
  3     CoreFoundation                        0x312b13cf -[NSInvocation invokeWithTarget:] + 50
  4     WebKit                                0x3395fe0d -[_WebSafeForwarder forwardInvocation:] + 252
  5     CoreFoundation                        0x31355a83 ___forwarding___ + 666
  6     CoreFoundation                        0x312b0650 _CF_forwarding_prep_0 + 48
  7     CoreFoundation                        0x313567e4 __invoking___ + 68
  8     CoreFoundation                        0x312b17b1 -[NSInvocation invoke] + 160
  9     WebCore                               0x31a851f5 _ZL11SendMessageP12NSInvocation + 24
  10   WebCore                                0x31a986f1 _ZL20HandleDelegateSourcePv + 80
  11   CoreFoundation                         0x31327ad3 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 14
  12   CoreFoundation                         0x3132729f __CFRunLoopDoSources0 + 214
  13   CoreFoundation                         0x31326045 __CFRunLoopRun + 652
  14   CoreFoundation                         0x312a94a5 CFRunLoopRunSpecific + 300
  15   CoreFoundation                         0x312a936d CFRunLoopRunInMode + 104
  16   GraphicsServices                       0x32782439 GSEventRunModal + 136
  17   UIKit                                  0x315aecd5 UIApplicationMain + 1080
  18   MyApp                              0x23e7 main (main.m:13)
  </code></pre>
  
  <p>In terms of narrowing this crash down, it only appears to happen on iOS 5.x on iPad.</p>
  
  <p>FWIW, in some areas of our codebase we're using WebViewDelegates and intercepting some of the user clicks on the links in the news stories. Not sure whether this could be a contributing factor, but thought it worthwhile to mention.</p>
  
  <p>Any ideas on what might be causing a crash at this section of code?</p>
  
  <p>Thanks,</p>
  
  <p>Sean</p>