Open Radar

 
Summary:
Saving another document on top of an existing open autosaved document causes the application to hang in -[NSFileCoordinator _blockOnAccessClaim:].

Steps to Reproduce:
1. Open TextEdit.
2. Save the untitled document in location X.
3. Create a new document.
4. Save the new document in location X, choosing to replace the existing document.

Expected Results:
Both document windows reflect the current state of the document on disk, or the first-opened window closes.

Actual Results:
TextEdit hangs indefinitely until the application with the open document is forced to quit.

Regression:
Preview also exhibits this behavior.

While the application is hung, other applications also hang when they attempt to save over the top of the document.

Notes:

Call graph:
    930 Thread_3750820   DispatchQueue_1: com.apple.main-thread  (serial)
    + 930 start  (in libdyld.dylib) + 1  [0x7fff87a617e1]
    +   930 NSApplicationMain  (in AppKit) + 869  [0x7fff888f2c06]
    +     930 -[NSApplication run]  (in AppKit) + 517  [0x7fff8894e1d3]
    +       930 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:]  (in AppKit) + 128  [0x7fff88956e22]
    +         930 _DPSNextEvent  (in AppKit) + 685  [0x7fff88957563]
    +           930 BlockUntilNextEventMatchingListInMode  (in HIToolbox) + 62  [0x7fff8a8a9ae3]
    +             930 ReceiveNextEventCommon  (in HIToolbox) + 356  [0x7fff8a8a9c52]
    +               930 RunCurrentEventLoopInMode  (in HIToolbox) + 209  [0x7fff8a8a9eb4]
    +                 930 CFRunLoopRunSpecific  (in CoreFoundation) + 290  [0x7fff85f320e2]
    +                   930 __CFRunLoopRun  (in CoreFoundation) + 1948  [0x7fff85f32c7c]
    +                     930 __CFRunLoopDoBlocks  (in CoreFoundation) + 255  [0x7fff85f0e47f]
    +                       930 __CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__  (in CoreFoundation) + 18  [0x7fff85f4dcd2]
    +                         930 __block_global_44  (in AppKit) + 175  [0x7fff88ca1652]
    +                           930 __block_global_232  (in AppKit) + 273  [0x7fff88c8f6aa]
    +                             930 -[NSDocument continueFileAccessUsingBlock:]  (in AppKit) + 222  [0x7fff88827999]
    +                               930 __block_global_233  (in AppKit) + 45  [0x7fff88c8f763]
    +                                 930 -[NSDocument _revertToVersion:preservingFirst:error:]  (in AppKit) + 186  [0x7fff88c6c49d]
    +                                   930 -[NSDocument performSynchronousFileAccessUsingBlock:]  (in AppKit) + 45  [0x7fff88827246]
    +                                     930 __53-[NSDocument _revertToVersion:preservingFirst:error:]_block_invoke_0  (in AppKit) + 349  [0x7fff88c6c63a]
    +                                       930 -[NSFileCoordinator coordinateReadingItemAtURL:options:error:byAccessor:]  (in Foundation) + 132  [0x7fff8f75a880]
    +                                         930 -[NSFileCoordinator(NSPrivate) _coordinateReadingItemAtURL:options:error:byAccessor:]  (in Foundation) + 604  [0x7fff8f75aaf5]
    +                                           930 -[NSFileCoordinator(NSPrivate) _blockOnAccessClaim:]  (in Foundation) + 202  [0x7fff8f75ae6c]
    +                                             930 _dispatch_semaphore_wait_slow  (in libdispatch.dylib) + 241  [0x7fff8e43c486]
    +                                               930 semaphore_wait_trap  (in libsystem_kernel.dylib) + 10  [0x7fff855376c2]