I am using widget with CoreData and iCloud. They share the same App Group container. Everything works fine for a little, but spontaneously widget starts constantly reload and block itself on the device screen and in Widget Dashboard (place where you can search and add any widget).
It happens on iPhone Simulator (I use iPhone 8) and on a physical device as well. On device it behaves better, e.g., it can reload for a while and then stop.
My thoughts that it is connected to NSPersistentContainer but I'm not sure. I've tried these with no luck:
lazily load everything that goes with Core Data: CoreDataStack, PersistentContainer, etc.
use container.performBackgroundTask() to return data in getTimeline(in:completion:) faster. I have tested with only 1 record, results are the same.
remove everything with Core Data and put example code to show static text - that works, reloads disappear, but I need to show real data
In deferent scenarios I see these log messages:
1) -[EXSwiftUI_Subsystem beginUsing:withBundle:] unexpectedly called multiple times
2) Bogus event received by listener connection
3) [lifecycle] WARNING: Did not receive handshake message from the host after waiting ~2 seconds. THIS MAY BE A SPURIOUS LAUNCH OF THE PLUGIN due to a message to an XPC endpoint other than the main service endpoint, or the CPU is highly contended and this extension or its host is not getting enough CPU time.
and sometimes crashes with
1) signal SIGTERM
2) [NSConcreteFileHandle fileDescriptor]: unknown error
I can't figure out why it happens. I confused because it sometimes works and show my Core Data records, and reloads timeline correctly, but sometimes it goes crazy.
Any help or guidance will be appreciated.
Xcode 12.0.1 (12A7300)
Device: iPhone Xs, iOS 14.0.1
Related
Im facing an issue that i am unable to debug.
If i open the app, it opens normally and works. But if i launch the app and close the app within 1 second and then launch the app again, it crashes without error message.
How do i debug this as Xcode loses debug connection if i close the app?
I tried putting exception break point but since xcode loses debug connection, it wont trigger.
This ONLY happens when a user does the above mentioned steps (open, close within 2 seconds and open again).
Is there anyway to find out why the app is closing and why there is no error / crash message?
Clarification : The crash happens when user opens the app, within 1 sec terminates the app by manually by swiping up from recents menu and tries to open the app again within 1 or 2 seconds. (Open -> terminate -> open)
Let us imagine that you run the app and quickly force-quit. Then, if you start your second run of the app from the Xcode debugger, hopefully, you should see your crash in Xcode at that point.
If that does not work, you might consider a crash reporting tool (e.g., Crashlytics, etc.). That will help you monitor and track crash reports that happen (for both you and your users) in the wild. If you do this, make sure you test the crash reporting system with some forced crash/report because an absence of a report could just be a result of a misconfiguration, which is easy to do because the setup of these tools takes a little work the first time you do it. Just make sure you have the crash report system working with a positive crash report before you draw any conclusions from an absence of a crash report generated by this particular bug.
That having been said, the way these crash reporting systems often work is they capture the crash and send it the next time you start up the app. It seems like there might be a chance that your particular crash (firing it up after having quickly force-quit it the first time) is happening so fast that the crash reporting system may not have a chance to send off its report of the past crash. (That having been said, these are still invaluable for capturing information about user crashes that happen during the normal use of the app, so I would consider them even if it does not help in this particular scenario.)
So, let’s imagine that you are still unsuccessful in catching your crash for some reason. The last resort is to consider sprinkling your code with Logger/OSLog statements. The nice thing about these logging statements is that you can watch these logging statements on your macOS Console app. See WWDC 2020 Explore logging in Swift.
I have one user (with an iPhone 5) reporting that my app crashes on launch about 15 seconds after the screen goes black (the splash screen is black). The user downloaded a TestFlight build where I included checkpoints in the App delegate, but I don't get evidence that those checkpoints are crossed, and I never get a crash report.
I changed the entry point on the storyboard to a blank view controller, and now I can see that the checkpoints are being crossed. It's occurred to me that Watchdog is suspending the app due to storyboard resources taking too long to load, but all the images are built in real-time as needed, with the exception of four tiny tab-bar icons. There are several audio files but they are loaded on demand. I can't think of any other resources that could be causing a delay. No one else has reported this problem, and I'm stumped.
Any insight appreciated, especially as to why I'm not seeing a crash report or checkpoints from TestFlight.
Your assumption is correct, the watchdog killed the app. This is because the app doesn't start up properly and either the main thread is blocked or no user interaction is possible since no UI is loaded.
As I understand your description, you are creating the resources while loading? And probably doing this on the main thread? You should try to offload resource hungry code into a background thread instead of doing this on the main thread where older/slower devices could take much longer than expected. The UI should always be responsive, the main thread should never ever to tasks that could get anywhere close to one second of processing.
Another reason could be that the link between the storyboard and the view controller is broken and it actually never loads on that device type.
But without more details it is impossible to say what exactly is going on.
In general: If the app is killed by the iOS system, e.g. by the watchdog due to startup time exceeding or due to allocating too much memory, then only iOS can generate a crash report.
The problem is that the app gets killed and in that case the process is killed. And that cannot be detected by any code running inside that process. And since crash reports on iOS, other than the iOS system based crash reporter, do run inside the same app process that is being killed, they cannot report or write any crash report.
The following page gives some more details on this: http://support.hockeyapp.net/kb/how-tos-faq/which-types-of-crashes-can-be-collected-on-ios-and-os-x (Though with context to PLCrashReporter, which is not used by Testflight. But the general statements are identical)
I updating my database with a lightweight migration. If I do the update on my device through xcode in debug mode everything runs fine. If I load the app through iTunes as a archive file it will crash before loading the rootViewController. This only happens with my large test database >100mb. I don't get anything useful in the crash log and am not sure what to do with this.
His is the only relevant line I can find in the crash log.
Unknown thread crashed with unknown flavor: 5, state_count: 1
Normally this would be reflected in the crash report (It would say something about failing to launch in time) but iOS devices expect you to get a view on the screen (or for ApplicationDidFinishLaunching to finish, I'm not sure exactly what it looks for) in a certain amount of time or it just gives up and closes the app. If you are doing a significant amount of work you'll want to get some kind of screen up before you start that work. Unfortunately this doesn't happen in a debug environment so it's a pain to test.
For an iPhone app that has to have a bunch of data inserted before the user can do their thing on first launch, where is the correct place (in the code) to insert that data? I'm looking at between 700 - 800 records total between a few tables.
I initially tried doing it in applicationDidFinishLaunching:. This worked fine for the iPhone 3gs, but caused a consistent first-launch crash on the 3g. After digging into the problem, i found that on the 3g, the app wasn't responding fast enough (presumably because it was busy dumping loads of data into the persistent store), so the OS was killing it under the assumption it was unresponsive.
To fix this problem, I moved the data initialization process out of appdidfinishlaunching and spawned another thread from the first view controller that shows upon launch. This works most of the time, but every once in a while the app crashes with a 134030 error in core data, which according to the apple constants reference, is:
NSPersistentStoreSaveError
Error code to denote that a persistent store returned an error for a save operation. This code pertains to errors such as permissions problems.
This error pops up when calling save: on the managedObjectContext.
Ideally towards the end of development you would populate this data into a Core Data store and add that to your project. On first run, you then copy that store from the app bundle over as the user's Core Data store. This should work for your case.
In the case where this is not possible, one would perform the import on a background thread.
I'm trying everything i can to get instruments to profile my app on the actual iphone device, but it won't work no matter what i do. I tried the solution from Does Instruments (ObjectAlloc/Leaks) require the simulator? but that didn't work. Most of the time i get nothing of use from the console, but one time i did receive this error:
Mon Aug 31 11:27:48 unknown
lockdownd[14] : (0x83d400)
handle_connection: Could not receive
USB message #13 from Instruments.
Killing connection
I'm not sure what could be causing this; has anyone else seen this and know a solution?
Same problem - it worked the first two times, then after that never again (even after restarting Xcode, deleiting the device, etc).
Eventually I resorted to:
Set XCode to display the Console
Run with Performance Tool
(instruments starts, and goes "BEEP"
with no error - Apple "forgot" to
include the error message, I think.
ARGH!)
Build&Run on device
Once the (gdb) appears in console,
go to Instruments and select "Attach
to Process" from the drop-down at
top
If you cannot see the name of your
debugging app, wait a second, and
try again
Eventually your app appears in the
list of alread-running stuff, so
select it
Hit the Record button
On subsequent runs, Instruments will remember the name of your app, but will show an error if you hit "record" too soon. So you just keep hitting record and doing "OK" on the process it tries to connect to until it stops messing around and does what it's supposed to.
So far (20 odd runs) this works everytime. Obviously, it would be nicer if it just worked properly, without this manual hackery, but Apple is reporting zero error messages even to system console, so there's nothing we can do!