Created attachment 243728 [details] Full crash backtrace Nightly builds of WebKit (SafariForWebKitDevelopment) have started exhibiting a consistent crash when choosing a tab from the all-tabs view (the "bird's-eye view"). Steps to reproduce: * Open Safari, with any page (homepage even if blank is sufficient) * Pinch with trackpad (OR click "Show All Tabs" button in top right in toolbar). * Observe tab in a scaled-down thumbnail in bird's-eye view (tab view). * Click on the tab to go back in. Expected behavior: Safari should zoom back into the tab, making the content active again. No crash. Actual behavior: Safari crashes completely. Thoughts: I think this is the most relevant part of the backtrace: *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSArrayM insertObject:atIndex:]: object cannot be nil' abort() called terminating with uncaught exception of type NSException Application Specific Backtrace 1: 0 CoreFoundation 0x00007fff8b9b566c __exceptionPreprocess + 172 1 libobjc.A.dylib 0x00007fff9268e76e objc_exception_throw + 43 2 CoreFoundation 0x00007fff8b861f39 -[__NSArrayM insertObject:atIndex:] + 1033 3 AppKit 0x00007fff8c41c50f -[NSView addGestureRecognizer:] + 220 4 WebKit 0x00000001064a2950 -[_WKThumbnailView _viewWasUnparented] + 59 5 AppKit 0x00007fff8bd24bf7 -[NSView _setWindow:] + 3274 6 CoreFoundation 0x00007fff8b8d6385 __53-[__NSArrayM enumerateObjectsWithOptions:usingBlock:]_block_invoke + 133 I've attached the full backtrace (which has more sys info).
<rdar://problem/19343307>
Created attachment 243773 [details] Patch
*** Bug 139952 has been marked as a duplicate of this bug. ***
Committed r177754: <http://trac.webkit.org/changeset/177754>
Any reason this can't be API tested?