macOS trace trap with 3.14.5

[n828cl]

Bug report

Bug description:

The attached datebox.py file causes a trace trap on macOS with 3.14.5, but runs correctly with 3.14.4. The full maOS problem report follows.

datebox.py

-------------------------------------
Translated Report (Full Report Below)
-------------------------------------
Process:             Python [35499]
Path:                /Library/Frameworks/Python.framework/Versions/3.14/Resources/Python.app/Contents/MacOS/Python
Identifier:          org.python.python
Version:             3.14.5 (3.14.5)
Code Type:           ARM-64 (Native)
Role:                Background
Parent Process:      zsh [1347]
Coalition:           com.apple.Terminal [1035]
Responsible Process: Terminal [1252]
User ID:             501

Date/Time:           2026-05-14 21:00:00.8954 -0500
Launch Time:         2026-05-14 21:00:00.1807 -0500
Hardware Model:      Mac17,5
OS Version:          macOS 26.5 (25F71)
Release Type:        User

Crash Reporter Key:  FE63E846-6AB3-55FD-4F00-445EF8F8438F
Incident Identifier: A7A56C7D-2C7F-4892-B9F0-901CD038EF1C

Sleep/Wake UUID:       C9ECEFCB-FEAD-4ACA-9F7E-BBE6827B2BB0

Time Awake Since Boot: 120000 seconds
Time Since Wake:       17185 seconds

System Integrity Protection: enabled

Triggered by Thread: 0, Dispatch Queue: com.apple.main-thread

Exception Type:    EXC_BREAKPOINT (SIGTRAP)
Exception Codes:   0x0000000000000001, 0x000000018edf7c88

Termination Reason:  Namespace SIGNAL, Code 5, Trace/BPT trap: 5
Terminating Process: exc handler [35499]


Thread 0 Crashed::  Dispatch queue: com.apple.main-thread
0   libobjc.A.dylib               	       0x18edf7c88 objc_opt_respondsToSelector + 48
1   Tk                            	       0x106dacb40 Tk_MacOSXGetTkWindow + 36
2   Tk                            	       0x106d9690c 0x106c20000 + 1534220
3   Tcl                           	       0x106b41374 TclServiceIdle + 216
4   Tcl                           	       0x106b03ba0 Tcl_DoOneEvent + 584
5   _tkinter.cpython-314-darwin.so	       0x101952114 _tkinter_tkapp_mainloop_impl + 184
6   Python                        	       0x101e82e7c _PyEval_EvalFrameDefault + 55852
7   Python                        	       0x101e73714 _PyEval_Vector + 576
8   Python                        	       0x101e73430 PyEval_EvalCode + 160
9   Python                        	       0x101f6873c run_mod + 232
10  Python                        	       0x101f68528 pyrun_file + 144
11  Python                        	       0x101f67f88 _PyRun_SimpleFileObject + 256
12  Python                        	       0x101f67900 _PyRun_AnyFileObject + 80
13  Python                        	       0x101f98330 pymain_run_file_obj + 164
14  Python                        	       0x101f97bbc pymain_run_file + 72
15  Python                        	       0x101f97398 Py_RunMain + 1528
16  Python                        	       0x101f98608 pymain_main + 480
17  Python                        	       0x101f9878c Py_BytesMain + 44
18  dyld                          	       0x18ee5fe00 start + 6992

Thread 1:

Thread 2:

Thread 3:

Thread 4:

Thread 5:

Thread 6:: com.apple.NSEventThread
0   libsystem_kernel.dylib        	       0x18f1d9c34 mach_msg2_trap + 8
1   libsystem_kernel.dylib        	       0x18f1ec574 mach_msg2_internal + 76
2   libsystem_kernel.dylib        	       0x18f1e29c0 mach_msg_overwrite + 480
3   libsystem_kernel.dylib        	       0x18f1d9fc0 mach_msg + 24
4   CoreFoundation                	       0x18f2db0d8 __CFRunLoopServiceMachPort + 160
5   CoreFoundation                	       0x18f2d99c4 __CFRunLoopRun + 1188
6   CoreFoundation                	       0x18f3ac1c4 _CFRunLoopRunSpecificWithOptions + 532
7   AppKit                        	       0x193829c7c _NSEventThread + 184
8   libsystem_pthread.dylib       	       0x18f21dc58 _pthread_start + 136
9   libsystem_pthread.dylib       	       0x18f218c1c thread_start + 8

Thread 7:
0   libsystem_kernel.dylib        	       0x18f1e4e80 __select + 8
1   Tcl                           	       0x106bb111c 0x106994000 + 2216220
2   libsystem_pthread.dylib       	       0x18f21dc58 _pthread_start + 136
3   libsystem_pthread.dylib       	       0x18f218c1c thread_start + 8


Thread 0 crashed with ARM Thread State (64-bit):
    x0: 0x00000008553fde00   x1: 0x0000000106dfa38c   x2: 0x0000000106dfa38c   x3: 0x0000000fffffc088
    x4: 0x0000000000000001   x5: 0x00000c0300000000   x6: 0x0000000000000002   x7: 0x0000000000000000
    x8: 0xa7620b58952f7b4c   x9: 0x00000000000001ac  x10: 0x00000008555d1ef9  x11: 0x00000000000000ff
   x12: 0x00000000000000c6  x13: 0x0000000855600c50  x14: 0x0900000106e2bd7f  x15: 0x0000000106e2bd78
   x16: 0x00620b58952f7b48  x17: 0x00000b58952f7b48  x18: 0x0000000000000000  x19: 0x00000001063d9620
   x20: 0x0000000000000000  x21: 0x0000000102218980  x22: 0x0000000101960c38  x23: 0x0000000102218980
   x24: 0x0000000102218980  x25: 0x0000000101960000  x26: 0x0000000101960000  x27: 0x0000000101960000
   x28: 0x0000000101960000   fp: 0x000000016f0e9f00   lr: 0x0000000106dacb40
    sp: 0x000000016f0e9ed0   pc: 0x000000018edf7c88 cpsr: 0x20000000
   far: 0x0000000000000000  esr: 0xf200c472 (Breakpoint) pointer authentication trap DA

Binary Images:
       0x100d14000 -        0x100d17fff org.python.python (3.14.5) <620d8cc3-53a5-3715-b6bb-49fe23e8e87f> /Library/Frameworks/Python.framework/Versions/3.14/Resources/Python.app/Contents/MacOS/Python
       0x101c78000 -        0x102133fff org.python.python (3.14.5) <1049a2ef-d0ad-3772-8837-7b1250f06bc5> /Library/Frameworks/Python.framework/Versions/3.14/Python
       0x100e40000 -        0x100e47fff zlib.cpython-314-darwin.so (*) <9097c715-0584-32a1-874e-f7167188af63> /Library/Frameworks/Python.framework/Versions/3.14/lib/python3.14/lib-dynload/zlib.cpython-314-darwin.so
       0x101178000 -        0x10117bfff _bz2.cpython-314-darwin.so (*) <63905268-729d-3d2c-8654-ddb8f6070c2e> /Library/Frameworks/Python.framework/Versions/3.14/lib/python3.14/lib-dynload/_bz2.cpython-314-darwin.so
       0x101998000 -        0x1019c7fff _lzma.cpython-314-darwin.so (*) <5b1d9c76-9d3d-3d47-a303-ddb2a89bc5f8> /Library/Frameworks/Python.framework/Versions/3.14/lib/python3.14/lib-dynload/_lzma.cpython-314-darwin.so
       0x101154000 -        0x10115ffff _zstd.cpython-314-darwin.so (*) <1285886a-8f37-3a0f-b33b-ca213d9688a3> /Library/Frameworks/Python.framework/Versions/3.14/lib/python3.14/lib-dynload/_zstd.cpython-314-darwin.so
       0x1019dc000 -        0x101ba7fff libzstd.1.5.7.dylib (*) <0a672331-97d6-3d5d-9898-3c4f851b25f0> /Library/Frameworks/Python.framework/Versions/3.14/lib/libzstd.1.5.7.dylib
       0x101950000 -        0x10195bfff _tkinter.cpython-314-darwin.so (*) <8d69005f-2106-3e23-8c72-e4180145b096> /Library/Frameworks/Python.framework/Versions/3.14/lib/python3.14/lib-dynload/_tkinter.cpython-314-darwin.so
       0x106994000 -        0x106beffff com.tcltk.tcllibrary (9.0.3) <6a440fdb-ca93-30d5-99b9-d38831dfde72> /Library/Frameworks/Python.framework/Versions/3.14/Frameworks/Tcl.framework/Versions/9.0/Tcl
       0x106c20000 -        0x106dfffff com.tcltk.tklibrary (9.0.3) <d745e867-38be-3010-b186-9c0f6b463845> /Library/Frameworks/Python.framework/Versions/3.14/Frameworks/Tk.framework/Versions/9.0/Tk
       0x106974000 -        0x10697ffff libobjc-trampolines.dylib (*) <ca58aa96-b997-3a6d-9132-19d49be4b3e9> /usr/lib/libobjc-trampolines.dylib
       0x18edb8000 -        0x18ee0ab4b libobjc.A.dylib (*) <ff1d8ae4-abef-35f1-a30a-1183b9cb414f> /usr/lib/libobjc.A.dylib
       0x18ee40000 -        0x18eee6217 dyld (*) <a237ef81-b68b-37ba-a165-92c965529534> /usr/lib/dyld
               0x0 - 0xffffffffffffffff ??? (*) <00000000-0000-0000-0000-000000000000> ???
       0x18f1d9000 -        0x18f2162af libsystem_kernel.dylib (*) <cc1cf985-bc65-3725-809f-4c1e36b8f4ba> /usr/lib/system/libsystem_kernel.dylib
       0x18f25d000 -        0x18f7bb31f com.apple.CoreFoundation (6.9) <04e3598b-f226-3250-b3b2-ce938dd4db7e> /System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation
       0x1936cf000 -        0x194df1f9f com.apple.AppKit (6.9) <cf57a4fc-4be3-3d95-b543-d744e8718b26> /System/Library/Frameworks/AppKit.framework/Versions/C/AppKit
       0x18f217000 -        0x18f223b3b libsystem_pthread.dylib (*) <4f33683c-18c8-39a1-800b-2e3bd43bcc13> /usr/lib/system/libsystem_pthread.dylib

External Modification Summary:
  Calls made by other processes targeting this process:
    task_for_pid: 0
    thread_create: 0
    thread_set_state: 0
  Calls made by this process:
    task_for_pid: 0
    thread_create: 0
    thread_set_state: 0
  Calls made by all processes on this machine:
    task_for_pid: 0
    thread_create: 0
    thread_set_state: 0

VM Region Summary:
ReadOnly portion of Libraries: Total=1.8G resident=0K(0%) swapped_out_or_unallocated=1.8G(100%)
Writable regions: Total=134.7M written=577K(0%) resident=577K(0%) swapped_out=0K(0%) unallocated=134.2M(100%)

                                VIRTUAL   REGION 
REGION TYPE                        SIZE    COUNT (non-coalesced) 
===========                     =======  ======= 
Activity Tracing                   256K        1 
AttributeGraph Data               1024K        1 
CoreGraphics                        32K        2 
Foundation                          16K        1 
Kernel Alloc Once                   32K        1 
MALLOC                            45.0M       19 
MALLOC guard page                 3360K        4 
Memory Tag 22                     64.0M        1 
Memory Tag 241                      16K        1 
STACK GUARD                        128K        8 
Stack                             19.3M        8 
VM_ALLOCATE                       4160K        8 
__AUTH                            5935K      621 
__AUTH_CONST                      88.4M     1006 
__CTF                               824        1 
__DATA                            35.1M      963 
__DATA_CONST                      35.0M     1022 
__DATA_DIRTY                      8298K      864 
__FONT_DATA                        2352        1 
__LINKEDIT                       574.6M       12 
__OBJC_RO                         79.1M        1 
__OBJC_RW                         2599K        1 
__TEXT                             1.2G     1044 
__TPRO_CONST                       128K        2 
dyld private memory                128K        1 
mapped file                      245.3M       28 
page table in kernel               577K        1 
shared memory                      864K       13 
===========                     =======  ======= 
TOTAL                              2.4G     5636 


-----------
Full Report
-----------

{"app_name":"Python","timestamp":"2026-05-14 21:00:04.00 -0500","app_version":"3.14.5","slice_uuid":"620d8cc3-53a5-3715-b6bb-49fe23e8e87f","build_version":"3.14.5","platform":1,"bundleID":"org.python.python","share_with_app_devs":1,"is_first_party":0,"bug_type":"309","os_version":"macOS 26.5 (25F71)","roots_installed":0,"name":"Python","incident_id":"A7A56C7D-2C7F-4892-B9F0-901CD038EF1C"}
{
  "uptime" : 120000,
  "procRole" : "Background",
  "version" : 2,
  "userID" : 501,
  "deployVersion" : 210,
  "modelCode" : "Mac17,5",
  "coalitionID" : 1035,
  "osVersion" : {
    "train" : "macOS 26.5",
    "build" : "25F71",
    "releaseType" : "User"
  },
  "captureTime" : "2026-05-14 21:00:00.8954 -0500",
  "codeSigningMonitor" : 2,
  "incident" : "A7A56C7D-2C7F-4892-B9F0-901CD038EF1C",
  "pid" : 35499,
  "translated" : false,
  "cpuType" : "ARM-64",
  "procLaunch" : "2026-05-14 21:00:00.1807 -0500",
  "procStartAbsTime" : 3091545864567,
  "procExitAbsTime" : 3091562572607,
  "procName" : "Python",
  "procPath" : "\/Library\/Frameworks\/Python.framework\/Versions\/3.14\/Resources\/Python.app\/Contents\/MacOS\/Python",
  "bundleInfo" : {"CFBundleShortVersionString":"3.14.5","CFBundleVersion":"3.14.5","CFBundleIdentifier":"org.python.python"},
  "storeInfo" : {"deviceIdentifierForVendor":"3947850C-E2D5-5D1E-BE46-4B3C336566BF","thirdParty":true},
  "parentProc" : "zsh",
  "parentPid" : 1347,
  "coalitionName" : "com.apple.Terminal",
  "crashReporterKey" : "FE63E846-6AB3-55FD-4F00-445EF8F8438F",
  "appleIntelligenceStatus" : {"reasons":["selectedLanguageDoesNotMatchSelectedSiriLanguage","selectedLanguageDoesNotMatchSelectedSiriLanguageInfo(system: en, siri: fr)"],"state":"unavailable"},
  "developerMode" : 1,
  "bootProgressRegister" : "0x2f000008",
  "responsiblePid" : 1252,
  "responsibleProc" : "Terminal",
  "codeSigningID" : "org.python.python",
  "codeSigningTeamID" : "BMM5U3QVKW",
  "codeSigningFlags" : 570491397,
  "codeSigningValidationCategory" : 6,
  "codeSigningTrustLevel" : 4294967295,
  "codeSigningAuxiliaryInfo" : 0,
  "instructionByteStream" : {"beforePC":"IAL4twgAQPkQzX2S8QMAqjFc7fIwGsHa8QMQqvFHwdofAhHrQAAAVA==","atPC":"QI441Ag+wHlIBPg24QMCquIDEKq\/Pv8XwANf1ggIQJLpLDbwKcESkQ=="},
  "bootSessionUUID" : "484F8216-6C2B-410D-B474-441CA0514FD2",
  "wakeTime" : 17185,
  "sleepWakeUUID" : "C9ECEFCB-FEAD-4ACA-9F7E-BBE6827B2BB0",
  "sip" : "enabled",
  "exception" : {"codes":"0x0000000000000001, 0x000000018edf7c88","rawCodes":[1,6691978376],"type":"EXC_BREAKPOINT","signal":"SIGTRAP"},
  "termination" : {"flags":0,"code":5,"namespace":"SIGNAL","indicator":"Trace\/BPT trap: 5","byProc":"exc handler","byPid":35499},
  "os_fault" : {"process":"Python"},
  "extMods" : {"caller":{"thread_create":0,"thread_set_state":0,"task_for_pid":0},"system":{"thread_create":0,"thread_set_state":0,"task_for_pid":0},"targeted":{"thread_create":0,"thread_set_state":0,"task_for_pid":0},"warnings":0},
  "faultingThread" : 0,
  "threads" : [{"triggered":true,"id":1796084,"threadState":{"x":[{"value":35789987328},{"value":4410286988},{"value":4410286988},{"value":68719460488},{"value":1},{"value":13207024435200},{"value":2},{"value":0},{"value":12061215227139554124},{"value":428},{"value":35791904505},{"value":255},{"value":198},{"value":35792096336},{"value":648518350751841663,"symbolLocation":648518346341351511,"symbol":"OBJC_METACLASS_$_TKNSString"},{"value":4410490232,"symbolLocation":80,"symbol":"OBJC_METACLASS_$_TKNSString"},{"value":27597022805588808},{"value":12475087944520},{"value":0},{"value":4399666720},{"value":0},{"value":4330719616,"symbolLocation":315120,"symbol":"_PyRuntime"},{"value":4321578040,"symbolLocation":0,"symbol":"state_key"},{"value":4330719616,"symbolLocation":315120,"symbol":"_PyRuntime"},{"value":4330719616,"symbolLocation":315120,"symbol":"_PyRuntime"},{"value":4321574912},{"value":4321574912},{"value":4321574912},{"value":4321574912}],"flavor":"ARM_THREAD_STATE64","lr":{"value":4409969472},"cpsr":{"value":536870912},"fp":{"value":6158196480},"sp":{"value":6158196432},"esr":{"value":4060136562,"description":"(Breakpoint) 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Graphics: Apple A18 Pro, Apple A18 Pro, Built-In
Display: Color LCD, spdisplays_2408x1506Retina, Main, MirrorOff, Online
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AirPort: spairport_wireless_card_type_wifi (0x14C3, 0x7932), MTK_driverkit-306.4 "MTK_driverkit-306.4" Apr 18 2026 17:49:14
IO80211_driverkit-1561.3 "IO80211_driverkit-1561.3" Apr 18 2026 17:42:26
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Bluetooth: Version (null), 0 services, 0 devices, 0 incoming serial ports
Network Service: Wi-Fi, AirPort, en0
Thunderbolt Bus: 

CPython versions tested on:

3.14

Operating systems tested on:

macOS

[aisk]

This works on main branch(461b1d9) with macOS 26.3.1:

[n828cl]

This works on main branch(461b1d9) with macOS 26.3.1:

Was that macOS 26.3.1 on Intel or ARM-64? The crash was with ARM-64 on macOS 26.5.

[aisk]

This works on main branch(461b1d9) with macOS 26.3.1:

Was that macOS 26.3.1 on Intel or ARM-64? The crash was with ARM-64 on macOS 26.5.

It's ARM64.

[ned-deily]

@n828cl You didn't state explicitly but it looks like you are using Python 3.14.5 from the python.org macOS installer, correct? With that I am able to reproduce the trace trap (M5 Mac, macOS 26.5).

The big difference between 3.14.5 and 3.14.4 with the installer is that 3.14.4 and earlier built and used Tk 8.6.x while 3.14.5 now uses Tk 9.0.3. So the most likely explanation is some difference between Tk 8.6.x and Tk 9.x, either in Tk or how tkinter calls Tk or how we build Tk or because of the installer build's use of the hardened run time at execution.

Your test program fails in a similar manner with the most recent python.org Python 3.15.0b1 pre-release which also uses the Tk 9.0.3 and is built in a similar manner to 3.14.5.

Before digging deeper into this by trying to reproduce with a debug build, perhaps @culler could take a quick look at the non-debug trace here to see if anything looks familiar.

[culler]

I certainly recognize the function Tk_MacOSXGetTkWindow. It is used throughout the macOS port of Tk to find the struct TkWindow associated with an instance of the objective C class NSWindow. Tk uses a subclass of NSWindow, named TKWindow, which adds, among other things, a method named tkWindow which returns a pointer to the associated struct TkWindow (cast to a long). The function Tk_MacOSXGetTkWindow is a small wrapper around that method which accepts a pointer to an Objective C object, checks whether that Objective C object responds to the selector tkWindow, and if so calls the method and returns the result.

The crash happens when checking if the object responds to the selector. The only reason I can find for respondsToSelector to cause a Trace/BPT trap is that the object has been deallocated. (Any method can be safely called on a NULL pointer). So that means that the real culprit here is the function listed as:
2 Tk 0x106d9690c 0x106c20000 + 1534220

In other words, we need the symbols. Somehow a deallocated NSWindow is being passed to Tk_MacOSXGetTkWindow.

I will see if I have debug version of Tk that I can run the test script against.

[n828cl]

@n828cl You didn't state explicitly but it looks like you are using Python 3.14.5 from the python.org macOS installer, correct? With that I am able to reproduce the trace trap (M5 Mac, macOS 26.5).

Yes, I did use the installer from python.org. Sorry for not stating that up front.

[culler]

So it turns out that the deallocated window which is causing this trace trap is the root window!

Lines 272 - 274 are:

272     root = tk.Tk()
273     themes = ttk.Style().theme_names()  # on macOS, aqua does not always honor config
274     root.destroy()

A Tk application quits as soon as its root window is destroyed. If you want to hide the root window you are supposed to call root.withdraw(), not root.destroy(). It amazes me that this script ever worked, given that it is destroying its root window immediately after creating it. The key seems to be that the script creates several different interpreters immediately after destroying the root of the first interpreter, and somehow those were able to keep running. Evidently the timing of the app termination after the destruction of its root happens faster in Tk 9 than it did in Tk 8, so those other interpreters don't get created. It is a Tk bug that the fact that the root had been destroyed was not detected by the call to Tk_MAcOSXGetTkWindow.

There are other issues with the script which arise after changing root.destroy() to root.withdraw(). It is attempting to
create a separate Tk interpreter for each available theme, and have the root window for each interpreter use the corresponding theme. The code seems to assume that calling ttk.Style.theme_use immediately after creating an interpreter will cause that interpreter to use the specified theme. That does not seem to be correct anymore.