I'm new to swift and am finding debugging to be particularly difficult. I"m using RubyMotion if that is relevant. After I log out a user and try to log back in I receive the following log:
2017-04-20 13:56:54.810 nav[8614:3232848] *** Assertion failure in -[UIView _layoutEngine_didAddLayoutConstraint:roundingAdjustment:mutuallyExclusiveConstraints:], /BuildRoot/Library/Caches/com.apple.xbs/Sources/UIKit_Sim/UIKit-3600.6.21/NSLayoutConstraint_UIKitAdditions.m:649
2017-04-20 13:56:54.927 nav[8614:3232848] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Impossible to set up layout with view hierarchy unprepared for constraint.'
*** First throw call stack:
(
0 CoreFoundation 0x0000000102ab5d4b __exceptionPreprocess + 171
1 libobjc.A.dylib 0x000000010141421e objc_exception_throw + 48
2 CoreFoundation 0x0000000102ab9e42 +[NSException raise:format:arguments:] + 98
3 Foundation 0x00000001038d466d -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 195
4 UIKit 0x0000000105a4d57b __120-[UIView(UIConstraintBasedLayout) _layoutEngine_didAddLayoutConstraint:roundingAdjustment:mutuallyExclusiveConstraints:]_block_invoke_2 + 206
5 UIKit 0x0000000105a4d417 -[UIView(UIConstraintBasedLayout) _layoutEngine_didAddLayoutConstraint:roundingAdjustment:mutuallyExclusiveConstraints:] + 418
6 UIKit 0x0000000105a4d7e8 -[UIView(UIConstraintBasedLayout) _tryToAddConstraintWithoutUpdatingConstraintsArray:roundingAdjustment:mutuallyExclusiveConstraints:] + 30
7 UIKit 0x0000000105a4d8fa -[UIView(UIConstraintBasedLayout) _tryToAddConstraint:roundingAdjustment:mutuallyExclusiveConstraints:] + 221
8 UIKit 0x0000000105a4dc0e __50-[UIView(UIConstraintBasedLayout) addConstraints:]_block_invoke + 208
9 Foundation 0x000000010385a3b0 -[NSISEngine withBehaviors:performModifications:] + 155
10 UIKit 0x0000000105a4db2f -[UIView(UIConstraintBasedLayout) addConstraints:] + 277
11 nav 0x00000001000d2ae2 __unnamed_64 + 98
12 nav 0x00000001004b495c vm_dispatch + 1372
13 nav 0x00000001004b8511 rb_scope__strain__ + 1313
14 nav 0x00000001009d9135 rb_vm_dispatch + 7221
15 nav 0x00000001004b495c vm_dispatch + 1372
16 nav 0x00000001004b7a3e rb_scope__initialize__ + 238
17 nav 0x00000001009d9135 rb_vm_dispatch + 7221
18 nav 0x000000010092ec57 rb_class_new_instance0 + 855
19 nav 0x00000001009d86e6 rb_vm_dispatch + 4582
20 nav 0x000000010076c1ec vm_dispatch + 1372
21 nav 0x0000000100780bc3 rb_scope__main_layout__ + 275
22 nav 0x00000001009d9135 rb_vm_dispatch + 7221
23 nav 0x000000010076c1ec vm_dispatch + 1372
24 nav 0x0000000100777955 rb_scope__layout__ + 133
25 nav 0x00000001009d9135 rb_vm_dispatch + 7221
26 nav 0x000000010076c1ec vm_dispatch + 1372
27 nav 0x0000000100778496 rb_scope__viewDidLoad__ + 534
28 nav 0x00000001007784ed __unnamed_67 + 13
29 UIKit 0x000000010522aa3d -[UIViewController loadViewIfRequired] + 1258
30 UIKit 0x0000000105231062 -[UIViewController __viewWillAppear:] + 118
31 UIKit 0x000000010525c1d3 -[UINavigationController _startCustomTransition:] + 1290
32 UIKit 0x000000010526ce48 -[UINavigationController _startDeferredTransitionIfNeeded:] + 697
33 UIKit 0x000000010526dfdb -[UINavigationController __viewWillLayoutSubviews] + 58
34 UIKit 0x0000000105464dd7 -[UILayoutContainerView layoutSubviews] + 223
35 UIKit 0x000000010514dab8 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 1237
36 QuartzCore 0x0000000104b4ebf8 -[CALayer layoutSublayers] + 146
37 QuartzCore 0x0000000104b42440 _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 366
38 QuartzCore 0x0000000104b422be _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 24
39 QuartzCore 0x0000000104ad0318 _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 280
40 QuartzCore 0x0000000104afd3ff _ZN2CA11Transaction6commitEv + 475
41 QuartzCore 0x0000000104afdd6f _ZN2CA11Transaction17observer_callbackEP19__CFRunLoopObservermPv + 113
42 CoreFoundation 0x0000000102a5a267 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23
43 CoreFoundation 0x0000000102a5a1d7 __CFRunLoopDoObservers + 391
44 CoreFoundation 0x0000000102a3ef8e __CFRunLoopRun + 1198
45 CoreFoundation 0x0000000102a3e884 CFRunLoopRunSpecific + 420
46 GraphicsServices 0x0000000107e57a6f GSEventRunModal + 161
47 UIKit 0x0000000105088c68 UIApplicationMain + 159
48 nav 0x00000001000a9fd2 main + 146
49 libdyld.dylib 0x0000000106f1b68d start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
What I'm struggling with is trying to find out where the error is in my code from the error logs.
Perhaps I'm spoiled but in ruby I'm used to a filename and line number being given where the error has been caused - is this something I can find out from this log?
Thanks in advance.