iOS crash, EXC_BREAKPOINT, No clue with Xcode 6.1 - ios

Question

I am usually able to solve the crashes but here I have not clue from where it comes from.
I use parse, and I am simply doing a request in background with a completion block.
The app crashes at a simple if condition and I can barely identify anything, no way to print description, ...
Do you have any idea ? A starting point ? anything ?
Xcode 6.1 is really strange, it seems that the debugger is buggy.
Here is the log of the crash :
Thread 0 name: Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0 libsystem_kernel.dylib 0x000000019657a964 __kill + 8
1 MyAPP 0x00000001001f2b70 0x10009c000 + 1403760
2 libsystem_platform.dylib 0x0000000196610958 _sigtramp + 64
3 MyAPP 0x00000001001318cc 0x10009c000 + 612556
4 MyAPP 0x000000010013797c 0x10009c000 + 637308
5 MyAPP 0x0000000100135fc4 0x10009c000 + 630724
6 MyAPP 0x00000001002e408c 0x10009c000 + 2392204
7 MyAPP 0x00000001001dbf78 0x10009c000 + 1310584
8 libdispatch.dylib 0x00000001964393a8 _dispatch_call_block_and_release + 20
9 libdispatch.dylib 0x0000000196439368 _dispatch_client_callout + 12
10 libdispatch.dylib 0x000000019643d97c _dispatch_main_queue_callback_4CF + 928
11 CoreFoundation 0x000000018566d69c __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 8
12 CoreFoundation 0x000000018566b744 __CFRunLoopRun + 1488
13 CoreFoundation 0x00000001855991f0 CFRunLoopRunSpecific + 392
14 GraphicsServices 0x000000018e7275a0 GSEventRunModal + 164
15 UIKit 0x0000000189eca780 UIApplicationMain + 1484
16 Shuff 0x0000000100129474 0x10009c000 + 578676
17 libdyld.dylib 0x0000000196462a04 start + 0
And here is a sample of the iOS code :
var query = PFQuery(className: "_User")
query.whereKey("facebookId", containedIn: ids)
query.findObjectsInBackgroundWithBlock(){
results, error in
if var resultsvar = results? {
self.functionToCall(resultsvar)
}
}
and the functionToCall crashes.
Maybe this can help :
0 0x00000001001679c8 in specialization of Swift._ArrayBuffer._nonNative.getter : Swift.Optional [inlined] ()

Answer 1

Yes !!! The debugger is not working well ! I was able to find the correct lines by doing the following : put a breakpoint at the start of where you think the app crashes, go step by step, remember the lowest line you've gone through. Even if the debugger crashes on another the line, the line you are looking for is probably the lowest one.

Answer 2

This is just a guess but I was working on something similar and I think you need to change this code to:
query.findObjectsInBackgroundWithBlock(){
results?, error? in
if var resultsvar = results {
self.functionToCall(resultsvar)
}
}
Note that I made both results and error optional. In my case I was providing a block defined in Obj-C, and in Obj-C these objects can legally be == nil. So I think you have to define them as optionals in Swift.