iOS 14 crash UITextField with textColor = [ UIColor colorWithCIColor: ]

Question

Crash:

- (void)viewDidLoad
{
    [ super viewDidLoad ];
    
    UITextField * textField = [ [ UITextField alloc ] init ];
    textField.textColor = [ UIColor colorWithCIColor:[ CIColor colorWithString:@"0 0 0 1" ] ];
    [ self.view addSubview:textField ];
}

Xcode console:

warning: could not execute support code to read Objective-C class data in the process. This may reduce the quality of type information available.

Don't crash:

- (void)viewDidLoad
{
    [ super viewDidLoad ];
    
    UITextField * textField = [ [ UITextField alloc ] init ];
    textField.text = @"text";
    textField.textColor = [ UIColor colorWithCIColor:[ CIColor colorWithString:@"0 0 0 1" ] ];
    [ self.view addSubview:textField ];
}

in empty project and empty UIViewController. iOS 14.2 / iPhone XS / Xcode 12.2 (12B45b).

Also it crash after clear all existing text in UItextFiled.

Answer 1

I verified this crash in a test app. Turns out, it's an infinitely-self-recursing, stack-delving kind of crash (see stack trace).

It's crashing because of the way you're initializing your UIColor from a CIColor. This is highly unconventional. CIColor objects really are meant to be used in the context of CoreImage.

If you do textField.textColor = [UIColor colorWithRed:0 green:0 blue:0 alpha:1]; there is no crash.

All this being said, your code probably shouldn't be crashing, and it's likely a bug in the API. It might be worth filing a bug report.