I'm troubleshooting a crash I do not understand.
I have a queue called DataQueue which never has anything dispatched to it - it's the sample buffer delegate of an AVCaptureVideoDataOutput. It can call DispatchQueue.main.sync to do some work on the main thread.
It works fine no matter what we test, but has some crashes in the field that I need to fix. Here's it crashing:
AppleCameraDataDelegate.dataQueue
0 libsystem_kernel.dylib 0x7bdc __ulock_wait + 8
1 libdispatch.dylib 0x4a80 _dlock_wait + 52
2 libdispatch.dylib 0x486c _dispatch_thread_event_wait_slow$VARIANT$mp + 52
3 libdispatch.dylib 0x113d8 __DISPATCH_WAIT_FOR_QUEUE__ + 332
4 libdispatch.dylib 0x10ff0 _dispatch_sync_f_slow + 140
The main thread isn't doing something I asked it to, but appears to be busy:
Thread
0 libsystem_kernel.dylib 0x71a4 __psynch_cvwait + 8
1 libsystem_pthread.dylib 0x7fd8 _pthread_cond_wait$VARIANT$mp + 1232
2 grpc 0x2cb670 gpr_cv_wait + 131 (sync.cc:131)
3 grpc 0x119688 grpc_core::Executor::ThreadMain(void*) + 225 (executor.cc:225)
4 grpc 0x2e023c grpc_core::(anonymous namespace)::ThreadInternalsPosix::ThreadInternalsPosix(char const*, void (*)(void*), void*, bool*, grpc_core::Thread::Options const&)::'lambda'(void*)::__invoke(void*) + 146 (thd.cc:146)
5 libsystem_pthread.dylib 0x482c _pthread_start + 104
6 libsystem_pthread.dylib 0xcd8 thread_start + 8
Can anyone help me understand why this is a crash?
Processes & Concurrency
RSS for tagDiscover how the operating system manages multiple applications and processes simultaneously, ensuring smooth multitasking performance.
Selecting any option will automatically load the page
Post
Replies
Boosts
Views
Activity
Started a new X-Code Project after updating to 26.0.1 and realized that I get an error when trying to mark a class as ObservableObject => "Class XYZ does not conform to Protocol 'ObservableObject'.
Strange behaviour, because at old projects the code is working even though the build options are the same and other settings like iOS version in Target are the same.
There must be something chaged under the hood of XCode? I have to import Combine now, before I could write my class, e.g. CoreData Datamanager: ObservableObject only using CoreData.
I've adopted the new BGContinuedProcessingTask in iOS 26, and it has mostly been working well in internal testing. However, in production I'm getting reports of the tasks failing when the app is put into the background.
A bit of info on what I'm doing: I need to download a large amount of data (around 250 files) and process these files as they come down. The size of the files can vary: for some tasks each file might be around 10MB. For other tasks, the files might be 40MB. The processing is relatively lightweight, but the volume of data means the task can potentially take over an hour on slower internet connections (up to 10GB of data).
I set the totalUnitCount based on the number of files to be downloaded, and I increment completedUnitCount each time a file is completed.
After some experimentation, I've found that smaller tasks (e.g. 3GB, 10MB per file) seem to be okay, but larger tasks (e.g. 10GB, 40MB per file) seem to fail, usually just a few seconds after the task is backgrounded (and without even opening any other apps). I think I've even observed a case where the task expired while the app was foregrounded!
I'm trying to understand what the rules are with BGContinuedProcessingTask and I can see at least four possibilities that might be relevant:
Is it necessary to provide progress updates at some minimum rate? For my larger tasks, where each file is ~40MB, there might be 20 or 30 seconds between progress updates. Does this make it more likely that the task will be expired?
For larger tasks, the total time to complete can be 60–90 mins on slower internet connections. Is there some maximum amount of time the task can run for? Does the system attempt some kind of estimate of the overall time to complete and expire the task on that basis?
The processing on each file is relatively lightweight, so most of the time the async stream is awaiting the next file to come down. Does the OS monitor the intensity of workload and suspend the task if it appears to be idle?
I've noticed that the task UI sometimes displays a message, something along the lines of "Do you want to continue this task?" with a "Continue" and "Stop" option. What happens if the user simply ignores or doesn't see this message? Even if I tap "Continue" the task still seems to fail sometimes.
I've read the docs and watched the WWDC video, but there's not a whole lot of information on the specific issues I mention above. It would be great to get some clarity on this, and I'd also appreciate any advice on alternative ways I could approach my specific use case.
I have an app for macOS that is built using Mac Catalyst. I need to perform some background processing. I'm using BGProcessingTaskRequest to schedule the request. I have also integrated CKSyncEngine so I need that to be able to perform its normal background processing.
On iOS, when the user leaves the app, I can see a log message that the request was scheduled and a bit later I see log messages coming from the actual background task code.
On macOS I ran the app from Xcode. I then quit the app (Cmd-q). I can see the log message that the request was scheduled. But the actual task is never run. In my test, I ran my app on a MacBook Pro running macOS 26.0. When I quit the app, I checked the log file in the app sandbox and saw the message that the task was scheduled. About 20 minutes later I closed the lid on the MacBook Pro for the night. I did not power down, it just went to sleep. Roughly 10 hours later I opened the lid on the MacBook Pro, logged in, and checked the log file. It had not been updated since quitting the app. I should also mention that the laptop was not plugged in at all during this period.
My question is, does a Mac Catalyst app support background processing after the user quits the app? If so, how is it enabled?
The documentation for BGProcessingTaskRequest and BGProcessingTask show they are supported under Mac Catalyst, but I couldn't find any documentation in the Background Tasks section that mentioned anything specific to setup for Mac Catalyst.
Running the Settings app and going to General -> Login Items & Extension, I do not see my app under the App Background Activity section. Does it need to be listed there? If so, what steps are needed to get it there?
If this is all documented somewhere, I'd appreciate a link since I was not able to find anything specific to making this work under Mac Catalyst.
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
CloudKit
macOS
Mac Catalyst
Background Tasks
Hello,
I'm experiencing an issue with my app where it's being terminated by the system with a watchdog violation during back-to-back messaging operations. I've analyzed the crash logs but would appreciate additional insights on optimizing my approach. I'd appreciate any insights on how to resolve this problem.
Crash Details:
Exception Type: EXC_CRASH (SIGKILL)
Termination Reason: FRONTBOARD with code 0x8BADF00D
Error: "scene-update watchdog transgression: app exhausted real time allowance of 10.00 seconds"
Reproduction Steps:
User A initiates back-to-back messages to other User
User A's UI becomes unresponsive and eventually the app crashes.
Stack Trace Analysis:
The crash occurs on the main thread, which appears to be blocked waiting for a condition in the keyboard handling system. The thread is stuck in [UIKeyboardTaskQueue _lockWhenReadyForMainThread] and related methods, suggesting an issue with keyboard-related operations during the messaging process.
Crash Tag
Exception Type: EXC_CRASH (SIGKILL)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Termination Reason: FRONTBOARD 2343432205
<RBSTerminateContext| domain:10 code:0x8BADF00D explanation:scene-update watchdog transgression: app<com.msikodiak.eptt(AD934F8A-DF57-4B75-BE73-8CF1A9A8F856)>:301 exhausted real (wall clock) time allowance of 10.00 seconds
ProcessVisibility: Foreground
ProcessState: Running
WatchdogEvent: scene-update
WatchdogVisibility: Background
WatchdogCPUStatistics: (
"Elapsed total CPU time (seconds): 6.390 (user 3.640, system 2.750), 11% CPU",
"Elapsed application CPU time (seconds): 0.020, 0% CPU"
)
ThermalInfo: (
"Thermal Level: 0",
"Thermal State: nominal"
) reportType:CrashLog maxTerminationResistance:Interactive>
Triggered by Thread: 0
Thread 0 name: Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0 libsystem_kernel.dylib 0x1e773d438 __psynch_cvwait + 8
1 libsystem_pthread.dylib 0x2210bc328 _pthread_cond_wait + 1028
2 Foundation 0x1957d8a64 -[NSCondition waitUntilDate:] + 132
3 Foundation 0x1957d8888 -[NSConditionLock lockWhenCondition:beforeDate:] + 80
4 UIKitCore 0x1998f1238 -[UIKeyboardTaskQueue _lockWhenReadyForMainThread] + 456
5 UIKitCore 0x19a3d775c __59-[UIKeyboardImpl updateAutocorrectPrompt:executionContext:]_block_invoke_9 + 28
6 UIKitCore 0x19986b084 -[UIKeyboardTaskQueue lockWhenReadyForMainThread] + 168
7 UIKitCore 0x19a3f2994 -[UIKeyboardTaskQueue waitUntilTaskIsFinished:] + 148
8 UIKitCore 0x19a3f2ac4 -[UIKeyboardTaskQueue performSingleTask:breadcrumb:] + 132
9 UIKitCore 0x199e2f7e4 -[_UIKeyboardStateManager updateForChangedSelection] + 144
10 UIKitCore 0x199e24200 -[_UIKeyboardStateManager invalidateTextEntryContextForTextInput:] + 92
11 WebKit 0x1ad52fa54 WebKit::PageClientImpl::didProgrammaticallyClearFocusedElement(WebCore::ElementContext&&) + 40
12 WebKit 0x1ad55adcc WebKit::WebPageProxy::didProgrammaticallyClearFocusedElement(WebCore::ElementContext&&) + 136
13 WebKit 0x1acec74e8 WebKit::WebPageProxy::didReceiveMessage(IPC::Connection&, IPC::Decoder&) + 18604
14 WebKit 0x1acd21184 IPC::MessageReceiverMap::dispatchMessage(IPC::Connection&, IPC::Decoder&) + 236
15 WebKit 0x1ace449b8 WebKit::WebProcessProxy::dispatchMessage(IPC::Connection&, IPC::Decoder&) + 40
16 WebKit 0x1ace44228 WebKit::WebProcessProxy::didReceiveMessage(IPC::Connection&, IPC::Decoder&) + 1764
17 WebKit 0x1acd1e904 IPC::Connection::dispatchMessage(WTF::UniqueRef<IPC::Decoder>) + 268
18 WebKit 0x1acd1e478 IPC::Connection::dispatchIncomingMessages() + 576
19 JavaScriptCore 0x1ae386b8c WTF::RunLoop::performWork() + 524
20 JavaScriptCore 0x1ae386960 WTF::RunLoop::performWork(void*) + 36
21 CoreFoundation 0x196badce4 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 28
22 CoreFoundation 0x196badc78 __CFRunLoopDoSource0 + 172
23 CoreFoundation 0x196bac9fc __CFRunLoopDoSources0 + 232
24 CoreFoundation 0x196babc3c __CFRunLoopRun + 840
25 CoreFoundation 0x196bd0700 CFRunLoopRunSpecific + 572
26 GraphicsServices 0x1e3711190 GSEventRunModal + 168
27 UIKitCore 0x1997ee240 -[UIApplication _run] + 816
28 UIKitCore 0x1997ec470 UIApplicationMain + 336
29 Telstra PTT 0x1004d30c8 main + 56
30 dyld 0x1bd5d3ad8 start + 5964
Hi,
I have a sandboxed app with a bundled sandboxed XPC service. When it’s launched, the XPC service registers a repeating XPC activity with the system. The activity’s handler block does get called regularly like I’d expect, but it stops being called once the main app terminates.
What’s the recommended way to fix this issue? Could I have a bundled XPC service double as a launch agent, or would that cause other problems?
For some reason, after invoking an unrelated dlclose() call to unload any .dylib that had previously been loaded via dlopen(..., RTLD_NOW), the subsequent call to task_info(mach_task_self(), TASK_DYLD_INFO, ...) syscall returns unexpected structure in dyld_uuid_info image_infos->uuidArray, that, while it seems to represent an array of struct dyld_uuid_info elements, there is only 1 such element (dyld_all_image_infos *infos->uuidArrayCount == 1) and the app crashes when trying to access dyld_uuid_info image->imageLoadAddress->magic, as image->imageLoadAddress doesn't seem to represent a valid struct mach_header structure address (although it looks like a normal pointer within the process address space. What does it point to?).
This reproduces on macOS 15.4.1 (24E263)
Could you please confirm that this is a bug in the specified OS build, or point to incorrect usage of the task_info() API?
Attaching the C++ file that reproduces the issue to this email message
It needs to be built on macOS 15.4.1 (24E263) via Xcode or just a command line clang++ compiler. It may crash or return garbage, depending on memory layout, but on this macOS build it doesn’t return a correct feedfacf magic number for the struct mach_header structure.
Thank you
Feedback Assistant reference: FB18431345
//On `macOS 15.4.1 (24E263)` create a C++ application (for example, in Xcode), with the following contents. Note, that this application should crash on this macOS build. It will not crash, however, if you either:
//1. Comment out `dlclose()` call
//2. Change the order of the `performDlOpenDlClose()` and `performTaskInfoSyscall()` functions calls (first performTaskInfoSyscall() then performDlOpenDlClose()).
#include <iostream>
#include <dlfcn.h>
#include <mach/mach.h>
#include <mach-o/dyld_images.h>
#include <mach-o/loader.h>
void performDlOpenDlClose() {
printf("dlopen/dlclose function\n");
printf("Note: please adjust the path below to any real dylib on your system, if the path below doesn't exist!\n");
std::string path = "/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/libswiftDemangle.dylib";
printf("Dylib to open: %s\n", path.c_str());
void* handle = ::dlopen(path.c_str(), RTLD_NOW);
if(handle) {
::dlclose(handle);
} else {
printf("Error: %s\n", dlerror());
}
}
void performTaskInfoSyscall() {
printf("Making a task_info() syscall\n");
printf("\033[34mSource File: %s\033[0m\n", __FILE__);
task_t task = mach_task_self();
struct task_dyld_info dyld_info;
mach_msg_type_number_t size = TASK_DYLD_INFO_COUNT;
kern_return_t kr = task_info(task, TASK_DYLD_INFO, (task_info_t)&dyld_info, &size);
if (kr != KERN_SUCCESS) {
fprintf(stderr, "task_info failed: %s\n", mach_error_string(kr));
}
const struct dyld_all_image_infos* infos =
(const struct dyld_all_image_infos*)dyld_info.all_image_info_addr;
printf("version: %d, infos->infoArrayCount: %d\n", infos->version, infos->infoArrayCount);
for(uint32_t i=0; i<infos->infoArrayCount; i++) {
dyld_image_info image = infos->infoArray[i];
const struct mach_header* header = image.imageLoadAddress;
printf("%d ", i);
printf("%p ", (void*)image.imageLoadAddress);
printf("(%x) ", header->magic);
printf("%s\n", image.imageFilePath);
fflush(stdout);
}
printf("\n\n");
printf("infos->uuidArrayCount: %lu\n", infos->uuidArrayCount);
for(uint32_t i=0; i<infos->uuidArrayCount; i++) {
dyld_uuid_info image = infos->uuidArray[i];
const struct mach_header* header = image.imageLoadAddress;
printf("%d ", i);
printf("%p ", (void*)image.imageLoadAddress);
printf("(%x)\n", header->magic);
fflush(stdout);
}
printf("task_info() syscall result processing is completed\n\n");
}
int main(int argc, const char * argv[]) {
performDlOpenDlClose();
performTaskInfoSyscall();
return 0;
}
Hey,
I have a user script that I have set up to run daily with launchd, the launchd logs indicate that the script is started but it's almost immediately exited with status 0. The odd thing is that it doesn't say that the script was killed or stopped in anyway, even though that is what seems to happen.
2024-12-04 14:15:04.970214 (gui/501/com.me.test) <Notice>: internal event: WILL_SPAWN, code = 0 2024-12-04 14:15:04.970320 (gui/501/com.me.test) <Notice>: service state: spawn scheduled 2024-12-04 14:15:04.970325 (gui/501/com.me.test) <Notice>: service state: spawning 2024-12-04 14:15:04.970431 (gui/501/com.me.test) <Notice>: launching: xpc event 2024-12-04 14:15:04.972067 (gui/501/com.me.test [26446]) <Notice>: xpcproxy spawned with pid 26446 2024-12-04 14:15:04.972096 (gui/501/com.me.test [26446]) <Notice>: internal event: SPAWNED, code = 0 2024-12-04 14:15:04.972107 (gui/501/com.me.test [26446]) <Notice>: service state: xpcproxy 2024-12-04 14:15:04.972160 (gui/501/com.me.test [26446]) <Notice>: internal event: SOURCE_ATTACH, code = 0 2024-12-04 14:15:04.998157 (gui/501/com.me.test [26446]) <Notice>: service state: running 2024-12-04 14:15:04.998180 (gui/501/com.me.test [26446]) <Notice>: internal event: INIT, code = 0 2024-12-04 14:15:04.998199 (gui/501/com.me.test [26446]) <Notice>: Successfully spawned shell_wrapper.sh[26446] because xpc event 2024-12-04 14:15:05.217482 (gui/501/com.me.test [26446]) <Notice>: exited due to exit(0), ran for 246ms 2024-12-04 14:15:05.217494 (gui/501/com.me.test [26446]) <Notice>: service state: exited 2024-12-04 14:15:05.217502 (gui/501/com.me.test [26446]) <Notice>: internal event: EXITED, code = 0 2024-12-04 14:15:05.217506 (gui/501 [100003]) <Notice>: service inactive: com.me.test 2024-12-04 14:15:05.217523 (gui/501/com.me.test [26446]) <Notice>: service state: not running
In the script itself I log at the end to indicate that it finished successfully, when ran with launchd I never reach this point however. The script also do two network requests and make a pause for between 5-10 seconds with time.sleep(paus) (python script). However the launchd log indicates that the script finished in 246ms.
Not sure what is going on, the script itself does not require any privileges above a normal user. I have tried running the script directly, and it works as expected. I have also tried evoking the script from launchd explicitly with: launchctl kickstart which starts the job but gives the same result as the scheduled job, except the log now says: `launching: non-ipc demand' instead.
I have also tried to remove the networking requests and replace them by reading data from a file without any sleep, no difference in outcome though.
I have generated the launchd plist file using Lingon.app and it's placed in ~/Library/LaunchAgents
Not sure what more information I can provide, but need some suggestion on how I can proceed help solving this.
Topic:
App & System Services
SubTopic:
Processes & Concurrency
We are building a 'server' application that can either run as a daemon or can run in background without showing any GUI. Basically, the end user can either configure this to run as a daemon so that it can be tied to the user's session or will launch the process which user will start and quit as needed.
I wanted to understand what is the recommended mechanism for such an application from Apple -
Should this application be built as a macOS Bundle ? Apple documentation also says that we should not daemonize the process by calling fork. Hence if we create a unix-style executable, will I not need to fork to make it run in a detached state when I launch the executable via double-click ? [Reference Link]
Is it fine to have an application on macOS which is a bundle but does not show any UI when launched by double click on the app-icon or via 'open'? While we have been able to achieve this by using NSApplicationMain and not showing the UI, was wondering if using CFRunLoop is best for this case as it is a non-gui application.
If we can get the right documentation link or recommendations on how we should build such an application which can run in a non-gui mode and also in a daemonized manner, it will help us.
Should the application be always built as a macos bundle or should it be a unix-style executable to support both the cases - by the same application/product and how should we look at the distribution of such applications.
Hello,
I have a question regarding the behavior of BGProcessingTaskRequest when the app is force-quit by the user via the App Switcher.
Based on common understanding and various discussions — including the following Apple Developer Forum threads:
Waking up an iOS app after app is … | Apple Developer Forums
Will BGAppRefreshTaskRequest will … | Apple Developer Forums
Background fetch after app is forc… | Apple Developer Forums
…it is widely understood that iOS prevents background execution (such as background fetch, push notifications, or BGTaskScheduler) after a user force-quits an app via the App Switcher.
However, in my app, I have observed that a scheduled BGProcessingTaskRequest still executes even after the app has been explicitly terminated via App Switcher. The task is scheduled using submit(_:error:), and it is clearly running some time after the app has been closed by the user.
That said, the task does run, but it appears to operate under tighter constraints — for example, it may be allowed to run for a shorter duration, and network requests appear to be more restricted compared to when the app is not force-quit.
My questions are:
Are there any documented or undocumented exceptions that allow this kind of behavior after force-quit?
Could this be a bug or a behavior change in recent iOS versions? (I am observing this on iOS 18.3, 18.4, and 18.5)
Any insights, experiences, or clarifications from Apple engineers or fellow developers would be greatly appreciated.
Thank you!
I have been experimenting with the BGContinuedProcessingTask API recently (and published sample code for it https://github.com/infinitepower18/BGContinuedProcessingTaskDemo)
I have noticed that if I lock the phone, the code that runs as part of the task stops executing. My sample code simply updates the progress each second until it gets to 100, so it should be completed in 1 minute 40 seconds. However, after locking the phone and checking the lock screen a few seconds later the progress indicator was in the same position as before I locked it.
If I leave the phone locked for several minutes and check the lock screen the live activity says "Task failed".
I haven't seen anything in the documentation regarding execution of tasks while the phone is locked. So I'm a bit confused if I encountered an iOS bug here?
When using conformance to ObservableObject and then doing async work in a Task, you will get a warning courtesy of Combine if you then update an @Published or @State var from anywhere but the main thread. However, if you are using @Observable there is no such warning.
Also, Thread.current is unavailable in asynchronous contexts, so says the warning. And I have read that in a sense you simply aren't concerned with what thread an async task is on.
So for me, that begs a question. Is the lack of a warning, which when using Combine is rather important as ignoring it could lead to crashes, a pretty major bug that Apple seemingly should have addressed long ago? Or is it just not an issue to update state from another thread, because Xcode is doing that work for us behind the scenes too, just as it manages what thread the async task is running on when we don't specify?
I see a lot of posts about this from around the initial release of Async/Await talking about using await MainActor.run {} at the point the state variable is updated, usually also complaining about the lack of a warning. But ow years later there is still no warning and I have to wonder if this is actually a non issue. On some ways similar to the fact that many of the early posts I have seen related to @Observable have examples of an @Observable ViewModel instantiated in the view as an @State variable, but in fact this is not needed as that is addressed behind the scenes for all properties of an @Observable type.
At least, that is my understanding now, but I am learning Swift coming from a PowerShell background so I question my understanding a lot.
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
Concurrency
Swift
SwiftUI
Combine
I have BGProcessingTask & BGAppRefreshTask working fine. The main purpose of my use of BGProcessingTask is to upload a file to AWS S3 using multipart/form-data. I have found that any file above about 2.5MB times out after running almost four minutes. If I run the same RESTful api using curl or Postman, I can upload a 25MB file in 3 seconds or less.
I have tried to deliberately set .earliestBeginDate to 01:00 or 02:00 local time on the iPhone, but that does not seem to help.
I use the delegate (yes, I am writing in Objective C) - URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend: and find that the iOS system uploads about 140kB every 15 seconds or so.
I am looking for recommendations or insight into how I might enable uploads of 25MB files. I would be happy it I could do just one a day for my use case.
I provide code on how I set up the NSURLSession and NSURLSessionDownloadTask, as it is my guess that if there is something that needs to be modified it is there.
I have to believe there is a solution for this since I read in many posts here and in StackOverflow how developers are using this functionality for uploading many, many files.
NSURLSessionConfiguration *sConf = [NSURLSessionConfiguration backgroundSessionConfigurationWithIdentifier:bkto.taskIdentifier];
sConf.URLCache = [NSURLCache sharedURLCache];
sConf.waitsForConnectivity = YES;
sConf.allowsCellularAccess = NO;
sConf.networkServiceType = NSURLNetworkServiceTypeVideot;
sConf.multipathServiceType = NSURLSessionMultipathServiceTypeNone;
sConf.discretionary = YES;
sConf.timeoutIntervalForResource = kONEHOURINTERVAL;
sConf.timeoutIntervalForRequest = kONEMINUTEINTERVAL;
sConf.allowsExpensiveNetworkAccess = NO ;
sConf.allowsConstrainedNetworkAccess = NO;
sConf.sessionSendsLaunchEvents = YES;
myURLSession = [NSURLSession sessionWithConfiguration:sConf delegate:self delegateQueue:nil];
And then later in the code...
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:pth]];
request.HTTPMethod = kHTTPPOST;
request.HTTPBody = [NSData my body data];
request.timeoutInterval = 60;
[request setValue:@"*/*" forHTTPHeaderField:@"Accept"];
[request setValue:@"en-us,en" forHTTPHeaderField:@"Accept-Language"];
[request setValue:@"gzip, deflate, br" forHTTPHeaderField:@"Accept-Encoding"];
[request setValue:@"ISO-8859-1,utf-8" forHTTPHeaderField:@"Accept-Charset"];
[request setValue:@"600" forHTTPHeaderField:@"Keep-Alive"];
[request setValue:@"keep-alive" forHTTPHeaderField:@"Connection"];
NSString *contType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",bnd];
[request setValue:contType forHTTPHeaderField:@"Content-Type"];
[request addValue:[NSString stringWithFormat:@"%lu",(unsigned long)myData.length] forHTTPHeaderField:@"Content-Length"];
and here are a few lines from my logs to show the infrequent multi-part uploads of only small chunks of data by the iOS system:
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: bytesSent = 393,216
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: totalBytesSent = 393,216
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: task = BackgroundDownloadTask <76A81A80-4703-4686-8742-A0048EB65108>.<2>, time Fri Mar 7 16:25:27 2025
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: bytesSent = 131,072
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: totalBytesSent = 524,288
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: task = BackgroundDownloadTask <76A81A80-4703-4686-8742-A0048EB65108>.<2>, time Fri Mar 7 16:25:42 2025
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: bytesSent = 131,072
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: totalBytesSent = 655,360
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: task = BackgroundDownloadTask <76A81A80-4703-4686-8742-A0048EB65108>.<2>, time Fri Mar 7 16:25:56 2025
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: bytesSent = 131,072
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: totalBytesSent = 786,432
Hello,
I have a few questions regarding the documentation here:
Can this method described in the article be built with Xcode 26 and run on iOS 26? Or is it restricted to run only on iOS 26, since AppExtensionPoint appears to be available starting from iOS 26?
Does this approach allow two apps under the same Team ID to communicate with each other?
Does this approach also allow two apps under different Team IDs to communicate with each other?
Is it mandatory to implement EXAppExtensionBrowserViewController and obtain user consent before using this method to exchange information?
In our implementation, we followed the documentation. Inside EXAppExtensionBrowserViewController, we were able to see the Generic Extension from another app and enabled the permission.
However, we still get the following error:
Failed to connect: Error Domain=NABUExtensionConnector Code=1
"No matching extension found"
UserInfo={NSLocalizedDescription=No matching extension found}
Could someone clarify whether this is expected behavior, or if we are missing an additional configuration step?
Thanks in advance!
What’s the recommended way to recursively walk through a directory tree using File Coordination? From what I understand, coordinating a read of a directory only performs a “shallow” lock; this would mean that I’d need to implement the recursive walk myself rather than use FileManager.enumerator(at:includingPropertiesForKeys:options:errorHandler:) plus a single NSFileCoordinator.coordinate(with:queue:byAccessor:) call.
I’m trying to extract information from all files of a particular type, so I think using NSFileCoordinator.ReadingOptions.immediatelyAvailableMetadataOnly on each file before acquiring a full read lock on it (if it’s the right file type) would make sense. Am I on the right track?
Hello,
https://developer.apple.com/forums/thread/802443
https://developer.apple.com/documentation/servicemanagement/updating-helper-executables-from-earlier-versions-of-macos
https://developer.apple.com/documentation/ServiceManagement/updating-your-app-package-installer-to-use-the-new-service-management-api#Run-the-sample-launch-agent
Read these.
Earlier we had a setup with SMJobBless, now we have migrated to SMAppService.
Everything is working fine, the new API seems easier to manage, but we are having issues with updating the daemon.
I was wondering, what is the right process for updating a daemon from app side?
What we are doing so far:
App asks daemon for version
If version is lower than expected:
daemon.unregister(), wait a second and daemon.register() again.
The why?
We have noticed that unregistering/registering multiple times, of same daemon, can cause the daemon to stop working as expected. The daemon toggle in Mac Settings -> Login Items & Extensions can be on or off, but the app can still pickup daemon running, but no daemon running in Activity monitor. Registration/unregistration can start failing and nothing helps to resolve this, only reseting with sfltool resetbtm and a restart seems to does the job. This is usually noticeable for test users, testing same daemon version with different app builds.
In production app, we also increase the bundle version of daemon in plist, in test apps we - don't.
I haven't found any sources of how the update of pre-bundled app daemon should work.
Initial idea is register/unregister, but from what I have observed, this seems to mess up after multiple registrations.
I have a theory, that sending the daemon a command to kill itself after app update, would load the latest daemon.
Also, I haven't observed for daemon, with different build versions to update automatically.
What is the right way to update a daemon with SMAppService setup?
Thank you in advance.
I need to check how long we can run an app in background which act as a consumer of data / control filter. What is the max time we get to run our app in background without any of these app strategies?
https://developer.apple.com/documentation/backgroundtasks/choosing-background-strategies-for-your-app
I am building an app that uses the SMAppService to register a LaunchDaemon that is bundled with my .app. I've got a priming flow created which walks the user through approving the service so that it will start on login.
However, I need to also be able to upgrade this background service if the user updates the app. To do this, I think I need to call unregisterAndReturnError and then registerAndReturnError.
From my testing, this seems to work correctly, but I have a concern. Will the user ever be prompted to re-authorize the LaunchDaemon that I am registering? If so, under what circumstances will that happen, and what does it look like (so that I can guide the user through it)?
Hi,
I built an Electron app that uses puppeteer-cluster to open a bundled version of Chrome. Everything works before packaging/signing with electron builder. Transporter does not report any issues and the app opens in TestFlight.
the Chrome.app is signed separately before running builder
hardenedRuntime = false
However, a permission error occurs when cluster attempts to launch Chrome:
Error: Unable to launch browser, error message: Failed to launch the browser process!
[0601/152740.225314:ERROR:bootstrap.cc(65)] bootstrap_check_in org.chromium.crashpad.child_port_handshake.9915.63117.BUEXLMXFWPLCEONM: Permission denied (1100)
[0601/152740.226091:ERROR:file_io.cc(94)] ReadExactly: expected 4, observed 0
[0601/152740.229808:ERROR:bootstrap.cc(65)] bootstrap_check_in org.chromium.crashpad.child_port_handshake.9913.63115.VVKELOQUCWUYPFMQ: Permission denied (1100)
[0601/152740.230244:ERROR:file_io.cc(94)] ReadExactly: expected 4, observed 0
[9911:45571:0601/152740.506968:ERROR:named_platform_channel_mac.cc(44)] bootstrap_check_in com.google.chrome.for.testing.apps.52995c87946bbcc94fc9a27df1478a13: Permission denied (1100)
[9911:62467:0601/152740.507564:FATAL:mach_port_rendezvous.cc(281)] Check failed: kr == KERN_SUCCESS. bootstrap_check_in com.google.chrome.for.testing.MachPortRendezvousServer.9911: Permission denied (1100)
at Cluster.<anonymous> (/Applications/MyApp.app/Contents/Resources/app.asar/node_modules/puppeteer-cluster/dist/Cluster.js:119:23)
at Generator.throw (<anonymous>)
at rejected (/Applications/MyApp.app/Contents/Resources/app.asar/node_modules/puppeteer-cluster/dist/Cluster.js:6:65)
at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
I'm wondering if it's an issue with entitlements, or something more.
The entitlements.mas.plist (aside from identifiers):
com.apple.security.app-sandbox
com.apple.security.cs.allow-jit
com.apple.security.cs.allow-unsigned-executable-memory
com.apple.security.cs.allow-dyld-environment-variables
com.apple.security.network.client
com.apple.security.network.server
com.apple.security.files.user-selected.read-write
com.apple.security.cs.disable-executable-page-protection
com.apple.security.files.user-selected.executable
I've spent many hours searching for a solution. Any help or insight would be greatly appreciated.
Topic:
App & System Services
SubTopic:
Processes & Concurrency
For a macOS GUI application (with a UIKit or AppKit entry point), I want to reliably capture diagnostic logs sent to stderr — especially useful when the app is launched from a terminal script or runs in the background, and traditional GUI elements (like alert dialogs) may not be viable. This is to log startup failures or even success messages for later inspection. However, when the app is launched via open MyApp.app, stderr redirection like open MyApp.app 2> log.txt does not capture any output — the file is created, but remains empty.
The only way I can capture stderr reliably is by bypassing the bundle and directly launching the binary inside with ./MyApp.app/Contents/MacOS/MyApp 2> ~/log.txt
This logs as expected, but is not the user-friendly or typical way to launch apps on macOS.
Double-clicking the app in Finder also does not show any stderr output.
Is there any recommended or supported way to redirect or access stderr output when launching a .app bundle via open, or any best practice for logging critical failures from a GUI app when terminal output isn't visible?
Topic:
App & System Services
SubTopic:
Processes & Concurrency