I am an iOS infrastructure developer at our company. Recently, many colleagues have encountered Xcode crash issues showing ((void *)0) == existingDocument. Basically, this issue occurs when setting breakpoints and the root cause is as follows: lldb needs to calculate the URL of the source code and tell Xcode to jump to the specified line of that file. Xcode will then try to find the corresponding document based on the URL. If it cannot find the document, it will create a new one. However, when adding a new document to the controller, it discovers that there is already an existing document with the same URL, which leads to a crash. It is possible that the process of finding and adding documents is not thread-safe and lacks locking mechanisms. For example, during debugging, if you enter a breakpoint and simultaneously open the corresponding source code file or switch to an inactive tab, this issue may occur. I would like to know how to solve this problem. ------------------------------------- Translated Report (Full Report Below) ------------------------------------- Process: Xcode [2005] Path: /Applications/Xcode14.1.app/Contents/MacOS/Xcode Identifier: com.apple.dt.Xcode Version: 14.1 (21534.1) Build Info: IDEFrameworks-21534001000000000~2 (14B47b) Code Type: ARM-64 (Native) Parent Process: launchd [1] User ID: 501 Date/Time: 2023-04-19 16:38:59.0906 +0800 OS Version: macOS 13.2 (22D49) Report Version: 12 Anonymous UUID: 2E59D9F5-77A9-4454-324D-54BBEFFB334F Sleep/Wake UUID: 3F42DEBA-451F-4B4B-94AB-E630D6AD6BE8 Time Awake Since Boot: 24000 seconds Time Since Wake: 9447 seconds System Integrity Protection: enabled Notes: dyld_process_snapshot_create_for_process failed with 5 Crashed Thread: 0 Dispatch queue: com.apple.main-thread Exception Type: EXC_CRASH (SIGABRT) Exception Codes: 0x0000000000000000, 0x0000000000000000 Application Specific Signatures: ((void *)0) == existingDocument Error Formulating Crash Report: dyld_process_snapshot_create_for_process failed with 5 Thread 0 Crashed:: Dispatch queue: com.apple.main-thread 0 libsystem_kernel.dylib 0x196466868 __pthread_kill + 8 1 libsystem_pthread.dylib 0x19649dcec pthread_kill + 288 2 libsystem_c.dylib 0x1963d62c8 abort + 180 3 IDEKit 0x105748b34 +[IDEAssertionHandler _handleAssertionWithLogString:assertionSignature:assertionReason:extraBacktrace:] + 980 4 IDEKit 0x105748f74 -[IDEAssertionHandler handleFailureInMethod:object:fileName:lineNumber:assertionSignature:messageFormat:arguments:] + 872 5 DVTFoundation 0x10217471c _DVTAssertionHandler + 424 6 DVTFoundation 0x10217489c _DVTAssertionFailureHandler + 196 7 IDEKit 0x10597fb2c -[IDEDocumentController addDocument:] + 960 8 IDEKit 0x105970e3c +[IDEDocumentController retainEditorDocument:] + 520 9 IDEKit 0x105972aa8 __66+[IDEDocumentController _retainedEditorDocumentForURL:type:error:]_block_invoke + 160 10 IDEKit 0x105971a04 +[IDEDocumentController performDocumentTransaction:] + 152 11 IDEKit 0x1059727f0 +[IDEDocumentController _retainedEditorDocumentForURL:type:error:] + 528 12 IDEKit 0x105972db8 +[IDEDocumentController retainedEditorDocumentForDocumentURL:documentType:forUseWithWorkspaceDocument:error:] + 68 13 IDEKit 0x105972cbc +[IDEDocumentController retainedEditorDocumentForDocumentLocation:forUseWithWorkspaceDocument:error:] + 180 14 DebuggerUI 0x2c2aad6e8 -[DBGVariablesViewContentProvider _updateAutoValues] + 344 15 DebuggerUI 0x2c2aac2d4 -[DBGVariablesViewContentProvider _autoVariablesList] + 60 16 DebuggerUI 0x2c2aac1c0 -[DBGVariablesViewContentProvider _autoVariablesListReady] + 60 17 DebuggerUI 0x2c2aac138 -[DBGVariablesViewContentProvider _filteredListNeedsUpdatingImmediately] + 616 18 Foundation 0x1974a3e60 __NSFireDelayedPerform + 372 19 CoreFoundation 0x19659754c __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 32 20 CoreFoundation 0x1965971f4 __CFRunLoopDoTimer + 940 21 CoreFoundation 0x196596d4c __CFRunLoopDoTimers + 356 22 CoreFoundation 0x19657c734 __CFRunLoopRun + 1896 23 CoreFoundation 0x19657b878 CFRunLoopRunSpecific + 612 24 HIToolbox 0x19fc5bfa0 RunCurrentEventLoopInMode + 292 25 HIToolbox 0x19fc5bde4 ReceiveNextEventCommon + 672 26 HIToolbox 0x19fc5bb2c _BlockUntilNextEventMatchingListInModeWithFilter + 72 27 AppKit 0x199801838 _DPSNextEvent + 632 28 AppKit 0x1998009c8 -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 728 29 DVTKit 0x101191888 -[DVTApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 300 30 AppKit 0x1997f4df8 -[NSApplication run] + 464 31 DVTKit 0x101190a90 -[DVTApplication run] + 60 32 AppKit 0x1997cc23c NSApplicationMain + 880 33 dyld 0x196173e50 start + 2544 Xcode-2023-04-19-163921.txt