UILabel [__NSCFString set]: unrecognized selector sent to instance crash - objective-c

Question

I am having a weird crash related to a UILabel but the crash reporting service I am using doesn't give me much help to locate it. I can't know which Controller and which UILabel is causing it. The only help I have is the following:
-[__NSCFString set]: unrecognized selector sent to instance 0x1e0958d0
0 CoreFoundation __exceptionPreprocess + 162
1 libobjc.A.dylib objc_exception_throw + 30
2 CoreFoundation -[NSObject(NSObject) doesNotRecognizeSelector:] + 170
3 CoreFoundation ___forwarding___ + 392
4 CoreFoundation _CF_forwarding_prep_0 + 24
5 UIKit -[UILabel _legacy_drawTextInRect:baselineCalculationOnly:] + 2632
6 UIKit -[UILabel _drawTextInRect:baselineCalculationOnly:] + 166
7 UIKit -[UILabel drawTextInRect:] + 450
8 UIKit -[UILabel drawRect:] + 72
9 UIKit -[UIView(CALayerDelegate) drawLayer:inContext:] + 364
10 QuartzCore -[CALayer drawInContext:] + 112
11 QuartzCore CABackingStoreUpdate_ + 1808
12 QuartzCore CA::Layer::display_() + 980
13 QuartzCore CA::Layer::display_if_needed(CA::Transaction*) + 202
14 QuartzCore CA::Layer::layout_and_display_if_needed(CA::Transaction*) + 24
15 QuartzCore CA::Context::commit_transaction(CA::Transaction*) + 238
16 QuartzCore CA::Transaction::commit() + 316
17 QuartzCore CA::Transaction::observer_callback(__CFRunLoopObserver*, unsigned long, void*) + 60
18 CoreFoundation __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 20
19 CoreFoundation __CFRunLoopDoObservers + 276
20 CoreFoundation __CFRunLoopRun + 742
21 CoreFoundation CFRunLoopRunSpecific + 356
22 CoreFoundation CFRunLoopRunInMode + 104
23 GraphicsServices GSEventRunModal + 74
24 UIKit UIApplicationMain + 1120
25 App main.m line 14
26 App start + 40
Is there anything I can find my way through this? Thanx in advance!

Answer 1

Even though it's an old question, for anyone that encounters a similar issue:
If you're using attributedText in your UILabel, check the attribute value types you're setting. For example:
NSString* s = #"str";
NSMutableAttributedString* as = [[NSMutableAttributedString alloc] initWithString:s];
[as addAttribute:NSForegroundColorAttributeName value:someObjectThatsNotAUIColor range:NSMakeRange(0, s.length)];
will cause the UILabel [__NSCFString set]: unrecognized selector sent to instance crash.

Answer 2

You could try to put this in a .h :
#interface NSString (extended)
- (void)set;
#end
And this in a .m :
#implementation NSString (extended)
- (void)set
{
NSLog(#"[NSString set] ??? impossible !!!");
}
#end
Then set a breakpoint on this method.

Answer 3

Search your project for " set]" then you'll probably already find it, as this is a very untypical method name. If that doesn't help, use NSLog to print out all your labels adresses to your console to find out which label is causing this. Like
for (UIView *sub in self.subviews)
if ([sub kindOfClass:[UILabel class]]) NSLog(#"%p", sub);
(code untested, correct spelling if necessary)