While running my application on macOS 27 today, it crashed in a strange way. The backtrace for the thread that crashed looks like it was some kind of Spotlight search indexing thread. The strange part is that my app makes no use of Spotlight and is not mentioned anywhere in the Spotlight section of System Prefs. Here is the backtrace, maybe something in here is enough of a clue as to what happened and why my App was running a Spotlight-related thread.
This was on 27 beta 1 (26A5353q), and the app is a video streaming app that uses both Qt 6.11.1 and SDL 3 and was rendering some frames with Metal at the time. The most unusual thing in the backtrace is the existence of ObjC params spelled both updatingDonationProgress as well as updatingDonationProgres.
Thread 8 Crashed:: Dispatch queue: com.apple.root.user-initiated-qos
0 libobjcMsgSend.dylib 0x19e7f0808 objc_msgSend + 8
1 CoreFoundation 0x1970fe300 __NSSetM_new + 368
2 CoreFoundation 0x19711cd64 -[NSSet initWithArray:range:copyItems:] + 304
3 LaunchServices 0x1976bc144 -[_LSLocalizedStringRecord _missingBundleLocsWithContext:tableID:unitID:unitBytes:] + 104
4 LaunchServices 0x197700628 objc_object* __strong __LSRECORD_GETTER__<objc_object* __strong>(LSRecord*, objc_selector*, objc_selector*) + 288
5 LaunchServices 0x1976bc854 -[_LSLocalizedStringRecord _detachFromContext:tableID:unitID:unitBytes:] + 68
6 LaunchServices 0x197701cac -[LSRecord detach] + 240
7 LaunchServices 0x197773720 -[UTTypeRecord _detachFromContext:tableID:unitID:unitBytes:] + 68
8 LaunchServices 0x1977756fc -[_UTDeclaredTypeRecord _detachFromContext:tableID:unitID:unitBytes:] + 52
9 LaunchServices 0x197701cac -[LSRecord detach] + 240
10 LaunchServices 0x197702c74 +[LSRecord(LSDetachable) resolveAllPropertiesOfRecords:count:andDetachOnQueue:] + 392
11 UniformTypeIdentifiers 0x19cd1bc80 +[UTType _typeWithTypeRecord:detachTypeRecord:findConstant:installInConstant:] + 232
12 UniformTypeIdentifiers 0x19cd19d38 _UTTypeGetForIdentifier(NSString*, bool) + 148
13 SpotlightKnowledge 0x2a7596adc -[SKGProcessor(EmbeddingsUtils) needsEmbeddingsForRecord:bundleID:] + 604
14 SpotlightKnowledge 0x2a7590bd4 -[SKGAttributeProcessor processorAttributesForRecord:bundleID:protectionClass:isUpdate:] + 500
15 CoreSpotlight 0x1a79bfa84 -[CSSearchableItemAttributeSet(CSPrivateAttributes) _standardizeProcessorAttributesForBundle:protectionClass:isUpdate:] + 292
16 CoreSpotlight 0x1a79b11a4 -[CSSearchableItem(Internal) standardizeAttributesForBundle:protectionClass:] + 780
17 CoreSpotlight 0x1a799f218 __39-[CSSearchableIndex _standardizeItems:]_block_invoke + 248
18 CoreFoundation 0x19712e56c __NSARRAY_IS_CALLING_OUT_TO_A_BLOCK__ + 24
19 CoreFoundation 0x197277604 ____NSCollectionHandleConcurrentEnumerationIfSpecified_block_invoke + 116
20 libdispatch.dylib 0x196ed45d4 _dispatch_client_callout2 + 16
21 libdispatch.dylib 0x196ecf2d4 _dispatch_apply_invoke3 + 336
22 libdispatch.dylib 0x196ed45bc _dispatch_client_callout + 16
23 libdispatch.dylib 0x196ebd624 _dispatch_once_callout + 32
24 libdispatch.dylib 0x196ecf974 _dispatch_apply_invoke_and_wait + 364
25 libdispatch.dylib 0x196ecea70 _dispatch_apply_with_attr_f + 1312
26 libdispatch.dylib 0x196ecebf4 dispatch_apply + 96
27 CoreFoundation 0x197277548 __NSCollectionHandleConcurrentEnumerationIfSpecified + 184
28 CoreFoundation 0x19712e350 -[__NSArrayM enumerateObjectsWithOptions:usingBlock:] + 188
29 CoreSpotlight 0x1a78d99b4 -[CSSearchableIndex _standardizeItems:] + 144
30 CoreSpotlight 0x1a799d4b0 -[CSSearchableIndex indexSearchableItems:deleteSearchableItemsWithIdentifiers:clientState:expectedClientState:clientStateName:updatingDonationProgress:protectionClass:forBundleID:options:reason:completionHandler:] + 824
31 CoreSpotlight 0x1a799d024 -[CSSearchableIndex indexSearchableItems:deleteSearchableItemsWithIdentifiers:clientState:expectedClientState:updatingDonationProgress:protectionClass:forBundleID:options:reason:completionHandler:] + 52
32 CoreSpotlight 0x1a799ca64 __131-[CSSearchableIndex endIndexBatchWithExpectedClientState:newClientState:critical:reason:updatingDonationProgres:completionHandler:]_block_invoke + 188
33 libsystem_trace.dylib 0x196d957e8 _os_activity_initiate_impl + 64
34 CoreSpotlight 0x1a799c91c -[CSSearchableIndex endIndexBatchWithExpectedClientState:newClientState:critical:reason:updatingDonationProgres:completionHandler:] + 448
35 AppKit 0x19c7a3568 0x19b5b6000 + 18797928
36 AppKit 0x19c4d8584 0x19b5b6000 + 15869316
37 libdispatch.dylib 0x196ebaa30 _dispatch_call_block_and_release + 32
38 libdispatch.dylib 0x196ed45bc _dispatch_client_callout + 16
39 libdispatch.dylib 0x196ec3018 _dispatch_lane_serial_drain + 744
40 libdispatch.dylib 0x196ec3b4c _dispatch_lane_invoke + 448
41 libdispatch.dylib 0x196ecdf70 _dispatch_root_queue_drain_deferred_wlh + 284
42 libdispatch.dylib 0x196ecd874 _dispatch_workloop_worker_thread + 720
43 libsystem_pthread.dylib 0x197076f78 _pthread_wqthread + 292
44 libsystem_pthread.dylib 0x197075cc4 start_wqthread + 8