iPhone app crash - how to read logs

bialek · 10-18-2011, 10:02 AM

Hi,
My app crashes sometimes and I have no idea why and where. Here is my log, but I don't know how to read it:

Code:

-[Order bytes]: unrecognized selector sent to instance 0x335070
 Stack: (
"0   My App                              0x00012de5 My App + 73189",
"1   My App                              0x00013047 My App + 73799",
"2   CoreFoundation                      0x36d15987 __handleUncaughtException + 74",
"3   libobjc.A.dylib                     0x320852d1 _objc_terminate + 128",
"4   libc++abi.dylib                     0x36d783c5 _ZL19safe_handler_callerPFvvE + 76",
"5   libc++abi.dylib                     0x36d78451 _ZdlPv + 0",
"6   libc++abi.dylib                     0x36d7979f __cxa_throw + 122",
"7   libobjc.A.dylib                     0x32085223 objc_exception_throw + 94",
"8   CoreFoundation                      0x36d18acb -[NSObject doesNotRecognizeSelector:] + 174",
"9   CoreFoundation                      0x36d17945 ___forwarding___ + 300",
"10  CoreFoundation                      0x36c72680 _CF_forwarding_prep_0 + 48",
"11  CoreFoundation                      0x36c64bdd CFDataGetBytePtr + 96",
"12  Foundation                          0x337af8db -[NSKeyedUnarchiver initForReadingWithData:] + 322",
"13  Foundation                          0x337d3651 +[NSKeyedUnarchiver unarchiveObjectWithData:] + 52",
"14  My App                              0x0000eef1 My App + 57073",
"15  Foundation                          0x337ada91 -[NSThread main] + 72",
"16  Foundation                          0x338415a1 __NSThread__main__ + 1048",
"17  libsystem_c.dylib                   0x37cb8c1d _pthread_start + 320",
"18  libsystem_c.dylib                   0x37cb8ad8 thread_start + 8"
)

Could someone help me?

Domele · 10-18-2011, 04:57 PM

You called a method named "bytes" on an "Order" object. This "Order" object does not implement a method named "bytes".

You are probably overreleasing something.

bialek · 10-19-2011, 02:07 AM

I understand what first row means. Problem is I don't call bytes method on that object.

Domele · 10-19-2011, 02:23 AM

Yep which means you are overreleasing your NSData object and an "Order" object took its memory block. So your pointer that pointed to an NSData object is now pointing to an "Order" object.

bialek · 10-19-2011, 02:59 AM

Thanks, but what can I do with that, I don't know where to search that.

nestedloop · 10-19-2011, 03:06 AM

Debug.

bialek · 10-19-2011, 03:14 AM

Yes I know this is best solution, but that error is on the live app and I can't reproduce that error in my project so I can't debug.

Domele · 10-19-2011, 03:16 AM

Well until you can reproduce it, you can't fix it. So keep trying to crash your app, you'll find it eventually.

nestedloop · 10-19-2011, 03:22 AM

@ bialek:

Try using Clang, the static code analyzer that comes with XCode ( you can do that by going to Build Menu -> Build and Analyze).

It will point out any illegal or irregular releases and other logical mistakes of the sort. You might find this particular one between them and solve your problem unknowingly.

Take care though, Clang is quite BETA-ish, sometimes it has false positives.

Cheers, and good luck!

bialek · 10-19-2011, 03:27 AM

That error occurs only after update to a new version, but don't appears in each user who updated the app only in few.
Could you tell me if problem can be here:
I have a custom class which I save in userdefaults using nskeyedarchiver. In that class I have an array with objects of that Order class (but before add it to that array I serialize order object also with nskeyedarchiver). In the new version I deleted one of the properties from that main custom class, but in nsuserdefaults was saved the old version. Maybe now should I delete that custom class from nsuserdefaults?

bialek · 10-19-2011, 03:29 AM

Quote:

Originally Posted by nestedloop

@ bialek:

Try using Clang, the static code analyzer that comes with XCode ( you can do that by going to Build Menu -> Build and Analyze).

It will point out any illegal or irregular releases and other logical mistakes of the sort. You might find this particular one between them and solve your problem unknowingly.

Take care though, Clang is quite BETA-ish, sometimes it has false positives.

Cheers, and good luck!

I make it all the time and there is no problems.

Domele · 10-19-2011, 05:13 PM

Nope, when you retrieve your object from NSData, it allocates a new object.

nestedloop · 10-20-2011, 01:58 AM

@Domele

OFFTOPIC: Dude, congratz! Your app is very very cool. And I love the texts on your site :P especially the one about how you don't lose your job with this app

) Keep up the good work

bialek · 10-20-2011, 02:00 AM

Thanks, but that means I have no more ideas where the problem can be.