Xcode 11 beta 7 playground hangs on save - always.

Running Mojave 10.14.6 on a new MacBook Pro

Xcode 11 beta 7 hangs when saving a .playground. All the time.


I've deleted and re-installed Xcode and the entire /Library/Developer directory, reset the path with xcode-select -r, and reinstalled Xcode Command Line Tools. Many times.


A typical Crash Log top looks like this:

Date/Time:       2019-09-07 22:03:05 -0700
End time:        2019-09-07 22:03:07 -0700
OS Version:      Mac OS X 10.14.6 (Build 18G95)
Architecture:    x86_64h
Report Version:  28


Data Source:     Stackshots
Shared Cache:    0x1094f000 D6BF345B-E109-37E2-A559-BF6F0E76564C


Command:         Xcode
Path:            /Users/USER/Downloads/Xcode-beta.app/Contents/MacOS/Xcode
Version:         ??? (???)
Parent:          launchd [1]
PID:             29477


Event:           hang
Duration:        2.89s (process was unresponsive for 56 seconds before sampling)
Steps:           29 (100ms sampling interval)


Hardware model:  MacBookPro15,1
Active cpus:     16


Time Awake Since Boot: 400000s
Time Since Wake: 210s




--------------------------------------------------
Timeline format: stacks are sorted chronologically
Use -i and -heavy to re-report with count sorting
--------------------------------------------------




Heaviest stack for the main thread of the target process:
  29  start + 1 (libdyld.dylib + 91093) [0x7fff682643d5]
  29  main + 541 (Xcode + 8205) [0x10312f00d]
  29  NSApplicationMain + 777 (AppKit + 10984) [0x7fff398e0ae8]
  29  -[NSApplication run] + 699 (AppKit + 79272) [0x7fff398f15a8]
  29  -[DVTApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 390 (DVTKit + 90363) [0x103a5a0fb]
  29  -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 1361 (AppKit + 103563) [0x7fff398f748b]
  29  _DPSNextEvent + 1135 (AppKit + 108445) [0x7fff398f879d]
  29  _BlockUntilNextEventMatchingListInModeWithFilter + 64 (HIToolbox + 44150) [0x7fff3b55fc76]
  29  ReceiveNextEventCommon + 603 (HIToolbox + 44773) [0x7fff3b55fee5]
  29  RunCurrentEventLoopInMode + 292 (HIToolbox + 45483) [0x7fff3b5601ab]
  29  CFRunLoopRunSpecific + 455 (CoreFoundation + 237246) [0x7fff3c300ebe]
  29  __CFRunLoopRun + 2772 (CoreFoundation + 240612) [0x7fff3c301be4]
  29  __CFRunLoopDoBlocks + 394 (CoreFoundation + 241287) [0x7fff3c301e87]
  29  __CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ + 12 (CoreFoundation + 489316) [0x7fff3c33e764]
  29  ___NSMainRunLoopPerformBlockInModes_block_invoke + 25 (AppKit + 6318132) [0x7fff39ee4834]
  29  __62-[NSDocumentController(NSInternal) _onMainThreadInvokeWorker:]_block_invoke_3 + 152 (AppKit + 6307961) [0x7fff39ee2079]
  29  ??? (IDEKit + 1804770) [0x104eab9e2]
  29  __119-[NSDocument(NSDocumentSaving) _fileCoordinator:asynchronouslyCoordinateReadingContentsAndWritingItemAtURL:byAccessor:]_block_invoke_2 + 89 (AppKit + 11931980) [0x7fff3a43f14c]
  29  ??? (IDEKit + 1803843) [0x104eab643]
  29  -[NSDocument(NSDocumentSerializationAPIs) continueFileAccessUsingBlock:] + 237 (AppKit + 6794157) [0x7fff39f58bad]
  29  ??? (IDEKit + 1804175) [0x104eab78f]
  29  __85-[NSDocument(NSDocumentSaving) _saveToURL:ofType:forSaveOperation:completionHandler:]_block_invoke_3.815 + 1902 (AppKit + 11941726) [0x7fff3a44175e]
  29  __85-[NSDocument(NSDocumentSaving) _saveToURL:ofType:forSaveOperation:completionHandler:]_block_invoke.908 + 440 (AppKit + 11947776) [0x7fff3a442f00]
  29  __85-[NSDocument(NSDocumentSaving) _saveToURL:ofType:forSaveOperation:completionHandler:]_block_invoke_2.911 + 231 (AppKit + 11948022) [0x7fff3a442ff6]
  29  ??? (IDEKit + 1821420) [0x104eafaec]
  29  -[NSDocument(NSDocumentSaving) _writeSafelyToURL:ofType:forSaveOperation:error:] + 28 (AppKit + 11911858) [0x7fff3a43a2b2]
  29  -[NSDocument(NSDocumentSaving) _writeSafelyToURL:ofType:forSaveOperation:forceTemporaryDirectory:error:] + 850 (AppKit + 11908562) [0x7fff3a4395d2]
  29  ??? (IDEPegasusPlaygroundEditor + 311569) [0x12b0e7111]
  29  ??? (IDEPegasusPlaygroundEditor + 462040) [0x12b10bcd8]
  29  -[NSDocument writeToURL:ofType:forSaveOperation:originalContentsURL:error:] + 444 (AppKit + 4572826) [0x7fff39d3a69a]
  29  -[NSDocument writeToURL:ofType:error:] + 401 (AppKit + 4573303) [0x7fff39d3a877]
  29  ??? (IDEPegasusPlaygroundEditor + 311809) [0x12b0e7201]
  29  ??? (IDEPegasusPlaygroundEditor + 464565) [0x12b10c6b5]
  29  ??? (IDEPegasusPlaygroundEditor + 311039) [0x12b0e6eff]
  29  ??? (IDEFoundation + 3065349) [0x104007605]
  29  ??? (DVTFoundation + 1074371) [0x1032954c3]
  29  ??? (DVTFoundation + 2719464) [0x103426ee8]
  29  ??? (DVTFoundation + 2886336) [0x10344fac0]
  29  _dispatch_lane_barrier_sync_invoke_and_complete + 60 (libdispatch.dylib + 61737) [0x7fff68223129]
  29  _dispatch_client_callout + 8 (libdispatch.dylib + 13885) [0x7fff6821763d]
  29  ??? (DVTFoundation + 1074943) [0x1032956ff]
  29  ??? (DVTFoundation + 1287265) [0x1032c9461]
  29  ??? (DVTFoundation + 2938754) [0x10345c782]
  29  ??? (DVTFoundation + 2936145) [0x10345bd51]
  29  ??? (DVTFoundation + 2933205) [0x10345b1d5]
  29  ??? (IDESwiftPackageSupport + 191186) [0x129088ad2]
  29  ??? (IDESwiftPackageSupport + 191684) [0x129088cc4]
  29  ??? (DVTFoundation + 2938754) [0x10345c782]
  29  ??? (DVTFoundation + 2936145) [0x10345bd51]
  29  ??? (DVTFoundation + 2933205) [0x10345b1d5]
  29  ??? (IDESwiftPackageSupport + 537778) [0x1290dd4b2]
  29  ??? (IDESwiftPackageSupport + 538299) [0x1290dd6bb]
  29  ??? (DVTFoundation + 1066103) [0x103293477]
  29  -[NSFileCoordinator coordinateReadingItemAtURL:options:error:byAccessor:] + 77 (Foundation + 825513) [0x7fff3e6128a9]
  29  -[NSFileCoordinator(NSPrivate) _coordinateReadingItemAtURL:options:error:byAccessor:] + 689 (Foundation + 826208) [0x7fff3e612b60]
  29  -[NSFileCoordinator(NSPrivate) _blockOnAccessClaim:withAccessArbiter:] + 377 (Foundation + 827942) [0x7fff3e613226]
  29  _dispatch_semaphore_wait_slow + 98 (libdispatch.dylib + 17311) [0x7fff6821839f]
  29  semaphore_wait_trap + 10 (libsystem_kernel.dylib + 4710) [0x7fff68399266]
*29  semaphore_wait_continue + 0 (kernel + 1935040) [0xffffff80003d86c0]




Process:         Xcode [29477]
UUID:            2304E81B-2EB2-3DE7-A271-C9E07E683F61
Path:            /Users/USER/Downloads/Xcode-beta.app/Contents/MacOS/Xcode
Architecture:    x86_64
Parent:          launchd [1]
UID:             501
Sudden Term:     Tracked
Footprint:       251.61 MB
Start time:      2019-09-07 22:03:05 -0700
End time:        2019-09-07 22:03:07 -0700
Num samples:     29 (1-29)
CPU Time:        0.020s (33.9M cycles, 14.6M instructions, 2.32c/i)
Note:            Unresponsive for 56 seconds before sampling
Note:            2 idle work queue threads omitted


  Thread 0x4d2ed6           DispatchQueue 109         29 samples (1-29)         priority 47 (base 47)
  
  29  start + 1 (libdyld.dylib + 91093) [0x7fff682643d5] 1-29
    29  main + 541 (Xcode + 8205) [0x10312f00d] 1-29
      29  NSApplicationMain + 777 (AppKit + 10984) [0x7fff398e0ae8] 1-29
        29  -[NSApplication run] + 699 (AppKit + 79272) [0x7fff398f15a8] 1-29
          29  -[DVTApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 390 (DVTKit + 90363) [0x103a5a0fb] 1-29
            29  -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 1361 (AppKit + 103563) [0x7fff398f748b] 1-29
              29  _DPSNextEvent + 1135 (AppKit + 108445) [0x7fff398f879d] 1-29
                29  _BlockUntilNextEventMatchingListInModeWithFilter + 64 (HIToolbox + 44150) [0x7fff3b55fc76] 1-29
                  29  ReceiveNextEventCommon + 603 (HIToolbox + 44773) [0x7fff3b55fee5] 1-29
                    29  RunCurrentEventLoopInMode + 292 (HIToolbox + 45483) [0x7fff3b5601ab] 1-29
                      29  CFRunLoopRunSpecific + 455 (CoreFoundation + 237246) [0x7fff3c300ebe] 1-29
                        29  __CFRunLoopRun + 2772 (CoreFoundation + 240612) [0x7fff3c301be4] 1-29
                          29  __CFRunLoopDoBlocks + 394 (CoreFoundation + 241287) [0x7fff3c301e87] 1-29
                            29  __CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ + 12 (CoreFoundation + 489316) [0x7fff3c33e764] 1-29
                              29  ___NSMainRunLoopPerformBlockInModes_block_invoke + 25 (AppKit + 6318132) [0x7fff39ee4834] 1-29
                                29  __62-[NSDocumentController(NSInternal) _onMainThreadInvokeWorker:]_block_invoke_3 + 152 (AppKit + 6307961) [0x7fff39ee2079] 1-29
                                  29  ??? (IDEKit + 1804770) [0x104eab9e2] 1-29
                                    29  __119-[NSDocument(NSDocumentSaving) _fileCoordinator:asynchronouslyCoordinateReadingContentsAndWritingItemAtURL:byAccessor:]_block_invoke_2 + 89 (AppKit + 11931980) [0x7fff3a43f14c] 1-29
                                      29  ??? (IDEKit + 1803843) [0x104eab643] 1-29                                        29  -[NSDocument(NSDocumentSerializationAPIs) continueFileAccessUsingBlock:] + 237 (AppKit + 6794157) [0x7fff39f58bad] 1-29
                                          29  ??? (IDEKit + 1804175) [0x104eab78f] 1-29
                                            29  __85-[NSDocument(NSDocumentSaving) _saveToURL:ofType:forSaveOperation:completionHandler:]_block_invoke_3.815 + 1902 (AppKit + 11941726) [0x7fff3a44175e] 1-29
                                              29  __85-[NSDocument(NSDocumentSaving) _saveToURL:ofType:forSaveOperation:completionHandler:]_block_invoke.908 + 440 (AppKit + 11947776) [0x7fff3a442f00] 1-29
                                                29  __85-[NSDocument(NSDocumentSaving) _saveToURL:ofType:forSaveOperation:completionHandler:]_block_invoke_2.911 + 231 (AppKit + 11948022) [0x7fff3a442ff6] 1-29
                                                  29  ??? (IDEKit + 1821420) [0x104eafaec] 1-29
                                                    29  -[NSDocument(NSDocumentSaving) _writeSafelyToURL:ofType:forSaveOperation:error:] + 28 (AppKit + 11911858) [0x7fff3a43a2b2] 1-29
                                                      29  -[NSDocument(NSDocumentSaving) _writeSafelyToURL:ofType:forSaveOperation:forceTemporaryDirectory:error:] + 850 (AppKit + 11908562) [0x7fff3a4395d2] 1-29
                                                        29  ??? (IDEPegasusPlaygroundEditor + 311569) [0x12b0e7111] 1-29
                                                          29  ??? (IDEPegasusPlaygroundEditor + 462040) [0x12b10bcd8] 1-29
                                                            29  -[NSDocument writeToURL:ofType:forSaveOperation:originalContentsURL:error:] + 444 (AppKit + 4572826) [0x7fff39d3a69a] 1-29
                                                              29  -[NSDocument writeToURL:ofType:error:] + 401 (AppKit + 4573303) [0x7fff39d3a877] 1-29
                                                                29  ??? (IDEPegasusPlaygroundEditor + 311809) [0x12