Swift SearchBar- [general] Connection to daemon was invalidated - swift

I just added a ui searchbar to my program, and every time i rerun the program I get the error-
[general] Connection to daemon was invalidated
Despite this, my app is able to run perfectly and I can't seem to tell what is wrong.
Does anyone know what this means and how I could fix this?
If you'd like to to take a look at my code, please let me know and I'll clean it up.

I am running my app on a physical device and I have the same issue. Looking at other threads on Stack Overflow, it appears that this is just a glitch in Xcode and probably not an issue on your part.
If you are using a physical device, try running it on a simulator - the error shouldn't appear (at least it didn't for me)

Related

How to debug if app closes without error message?

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.

iPhone app crashes randomly without any error or stack trace

I am new here . Sorry if I this question is being repeated but I have a slightly different issue than the others.
My app crashes randomly after certain amount of time interval without any error logs or stack trace. I suspect it's an memory issue . I have the following questions :
1.) How to get stack trace (I have tried NSZombie enabled and NSUnacughtExcpetion handler) but didn't worked
2.) I get Memory warning frequently in my app. How do I confirm whether it's the prime suspect for the above issue? (I have used Leaks, my app crashes when it has just 4Mb usage so I am not quite sure whether memory leak is causing it my app to crash. I know certain application which take heap memory more than 4MB .)
3.) What is the upper limit for Memory leak for an application in iOS before app crashes ?
4.) Would ARC help me in this situation ?
Also, I have tried to debug issue using NSLog statements but since it crashes randomly , it would be hard for me to detect the root cause using this technique.
Any ideas would be or help would be really appreciated
My app crashes randomly after certain amount of time interval without any error logs or stack trace. I suspect it's an memory issue.
To confirm that it's a memory issue, sync your device with iTunes,and look in ~/Library/Logs/CrashReporter/MobileDevice/ for a files with LowMemory in their name. If you see (jettisoned) next to your app name, that confirms it was killed by iOS for using too much memory.
The only other way an app could exit without leaving a crash report is if it erroneously called exit().
For more information, see "Debugging Deployed iOS Apps", and "Understanding and Analyzing iOS Application Crash Reports".
Not sure but reading the registers might help.
First go to Exceptions tab and 'Add Exception Breakpoint' using the + at the bottom left corner.
Then when the app crashes click on "0 objc_exception_throw" under Thread 1
Finally in the console enter:
register read
(you should get a list of registers)
po $rax (normally the exception is in 'rax')
(you should see the exception output on the console)
Hope this helps.
That does sound like maybe the device is running low on memory and shutting you down. There's lots of threads on stackoverflow on debugging memory warnings.
This one talks a little about what to look for when using the Instruments tool.
Here is an explanation of how to get the memory warning level, and what the codes mean.
There is no fixed memory limit on iPhones. I've asked Apple support representatives this question, and they wouldn't give me a fixed answer (probably because the algorithm does not actually enforce any one hard limit for a 3rd-party app).
And, yes, ARC can be a wonderful thing. In your situation, you might have to rework a lot of code to make it all ARC-compliant, but ARC is definitely a useful feature, and can produce programs with fewer memory problems, with less work by the coders (leaving you more time to fix other problems!)
I recommend instrument
https://developer.apple.com/library/mac/#documentation/developertools/conceptual/InstrumentsUserGuide/AboutTracing/AboutTracing.html
In my case i closed all other apps and it started working normally, maybe it was a memory issue

iOS app crashes with no error, just (lldb)

My application lately seems to randomly crash with no error or exceptions. The console just shows (lldb) in light blue. I have uncaught exception handling and still nothing. It happens at random times. I can do the same task over and over and sometimes it will happen and sometimes it won't. Also sometimes it will happen in random places within the application.
So far what I have read is it is possibly just the lldb debugger crashing and not my app however I haven't noticed it before.
Any ideas how to figure out what the cause of the crash is?
It seems to have started when I added MBProgressHUD to my application.
I also just encountered a similar error - where I was just getting a blue lldb in the console with no additional info. However I was getting an exc_bad_access in the debug navigator so I knew it had to be a memory problem. I ended up tracing it to a release command I should not have been making . . .
Are you getting any details of the error in the debug navigator?
If yes please provide.
An over released object might explain why the app would be crashing at random times since (from what I understand) the system won't always immediately dealloc your object just because you sent it a release command however it will do it sooner or later.
I ended up using crittercism and testflight crash reporting to help find the area where it was occurring. It looks like it was because I was running core data on a background thread.
I have been trying to fix this issue for the last 2 hours or so and I turned out I simply had a break point in Xcode. This might not be the case for you but if anyone stumbles upon this thread, check your breakpoints.
In Xcode click this arrow then right click your breakpoints and delete them.
Not sure if this will be helpful to anyone or if I was just being stupid, but save yourself 2 hours and check your breakpoints :)

Iphone main thread crashes but app still running - "program received signal 0"

so when i'm running my app using XCode and I can see that my app gets "program received signal 0".
However , the background thread are still running. why is that ?
Second, I can't seem to find any solution to this problem.
I assumed it might be memory leak, but I see nothing special using LEAKS (instrument).
When I run the app on the device(without XCode) and then try to see the device crash inside the organizer, most of the times there is no log (I guess maybe because the app is still running and only the main thread crashed) and while there is a log, my app function are only hex addresses without names.
What other options do I have to solve this issues ?
Thanks!!
I've found that sometimes these errors are caused by trying to access deallocated memory. One great tool to debug these issues is NSZombieEnabled. Here's a link to a good explanation of how to use NSZombieEnabled: CocoaDev: NSZombieEnabled

Unable to run instruments on my iphone app on the device

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!