UIEdgeInset custom initializer in extension throwing EXC_BAD_ACCESS - swift

Question

I have this extension:
extension UIEdgeInsets {
init(top: CGFloat = 0, left: CGFloat = 0, bottom: CGFloat = 0, right: CGFloat = 0) {
self.init(top: top, left: left, bottom: bottom, right: right)
}
}
The purpose of the extension is to not have to pass parameters to the UIEdgeInsets initializer when they're not different from the default values. But when the custom initializer runs, an error is thrown:
Thread 1: EXC_BAD_ACCESS (code=2, address=0x16f997ff8)
Any idea why this code would cause a runtime error?

Answer 1

You are causing infinite recursion since you are calling the same init method from within itself.
And an extension really shouldn't try to override an existing init or other method simply by providing default parameters.
There is already an init(top:,left:,bottom:,right:). Providing another with the same signature is a bad idea.
But that aside, your primary issue is calling self.init from within the same init method.
To see the problem, add a print statement:
init(top: CGFloat = 0, left: CGFloat = 0, bottom: CGFloat = 0, right: CGFloat = 0) {
print("Uh-oh")
self.init(top: top, left: left, bottom: bottom, right: right)
}
As another example, create a class with an init that takes one parameter. Now add the same init again to the class but provide a default to the parameter. The code won't even compile. So trying to do the same through an extension is just going to lead to problems, even if you could solve the recursion problem.