Exception on unarchiving node icon

[jjac]

When a folder node (like Movies or Photo Booth) is unarchived in the app's process after being sent from the folder XPC service it often (but not always) causes the following exception to be thrown:

iMediaTester[55258:303] * Terminating app due to uncaught exception 'NSRangeException', reason: '* -[NSArrayI objectAtIndex:]: index 0 beyond bounds for empty array' *\ First throw call stack: ( 0 CoreFoundation 0x00007fff96ed7716 exceptionPreprocess + 198 1 libobjc.A.dylib 0x00007fff9779c470 objc_exception_throw + 43 2 CoreFoundation 0x00007fff96e8a803 -[NSArrayI objectAtIndex:] + 163 3 AppKit 0x00007fff8cc82d1a -[NSImage initWithCoder:] + 3871 4 Foundation 0x00007fff96404c39 _decodeObjectBinary + 2741 5 Foundation 0x00007fff96403fe4 _decodeObject + 226 6 iMedia 0x0000000100031be8 -[IMBNode initWithCoder:] + 1960 7 Foundation 0x00007fff96404c39 _decodeObjectBinary + 2741 8 Foundation 0x00007fff96403fe4 _decodeObject + 226 9 Foundation 0x00007fff964770d3 +[NSKeyedUnarchiver unarchiveObjectWithData:] + 92 10 XPCKit 0x00000001001836ab +[NSData(XPCParse) objectWithXPCObject:] + 123 11 XPCKit 0x0000000100183391 +[NSObject(XPCParse) objectWithXPCObject:] + 257 12 XPCKit 0x0000000100183b79 50+[NSArray(XPCParse) arrayWithContentsOfXPCObject:]_block_invoke_0 + 57 13 libxpc.dylib 0x00007fff94971db8 xpc_array_apply + 50 14 XPCKit 0x0000000100183b03 +[NSArray(XPCParse) arrayWithContentsOfXPCObject:] + 179 15 XPCKit 0x0000000100183318 +[NSObject(XPCParse) objectWithXPCObject:] + 136 16 XPCKit 0x000000010018536c -[XPCMessage objectForKey:] + 124 17 XPCKit 0x0000000100186505 -[XPCMessage(XPCKitInternal) invocationReturnValue:] + 53 18 XPCKit 0x0000000100181644 __67-[XPCConnection sendSelector:withTarget:object:returnValueHandler:]_block_invoke_0 + 68 19 XPCKit 0x000000010018122f block_global_0 + 383 20 libxpc.dylib 0x00007fff9497083c _xpc_connection_call_reply + 31 21 libdispatch.dylib 0x00007fff931e70fa _dispatch_client_callout + 8 22 libdispatch.dylib 0x00007fff931ec104 _dispatch_main_queue_callback_4CF + 275 23 CoreFoundation 0x00007fff96e7981e CFRunLoopRun + 1614 24 CoreFoundation 0x00007fff96e78dd2 CFRunLoopRunSpecific + 290 25 HIToolbox 0x00007fff9442d774 RunCurrentEventLoopInMode + 209 26 HIToolbox 0x00007fff9442d512 ReceiveNextEventCommon + 356 27 HIToolbox 0x00007fff9442d3a3 BlockUntilNextEventMatchingListInMode + 62 28 AppKit 0x00007fff8ccc5fa3 _DPSNextEvent + 685 29 AppKit 0x00007fff8ccc5862 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 128 30 AppKit 0x00007fff8ccbcc03 -[NSApplication run] + 517 31 AppKit 0x00007fff8cc61656 NSApplicationMain + 869 32 iMediaTester 0x0000000100005067 main + 119 33 iMediaTester 0x00000001000017f4 start + 52 )

Also note the following circumstances:

• This exception will only be thrown if you remove the try/catch block in NSData+XPCParse.h in XPCKit (otherwise you will probably see a consequential error)
• This problem occurs almost solely if you run the application sandboxed (i.e. with XPC Services)
• Not always the same icon seems to be the cause
• If you archive and unarchive the NSImage right after it is created (-[IMBParser iconForItemAtURL:error:]) you can provoke the error immediately (i.e. without crossing process boundaries)
• Could only reproduce the problem when being in the Movies section

The problem seems to be gone after I updated the "Photo Booth" directory to the new "Photo Booth Library"

This is a hard one.

[peterb180369]

Made this more robust by catching the exception and substituting a generic folder icon in this case.

[peterb180369]

This solution should suffice, so I'm closing this issue.