Note that your code will not work; you've shadowed 's' inside the if block because you have 'if s, err := ...'. As a result, 's = defaults()' will set the shadowed 's' variable that only exists within the if block to defaults, but the 'var s Settings' you declared above will not be modified.

Here's a playground showing the issue: https://play.golang.org/p/eE0HEZx1MJu

Go is full of nice little foot-guns like that :)

You would want to also have 'var err error' above the block and use '=' instead of ':=' to fix this sort of issue.

I am by no means an expert (or even a frequent user) of go. However, the most unfortunate foot cannon I have encountered is this:

    package main
    
    type HowOdd interface {
    	Poke() string
    }
    
    type AConcreteThing struct {
    }
    
    func (t *AConcreteThing) Poke() string { return "hehe" }
    
    func DoAConcreteThing() *AConcreteThing {
    	return nil
    }
    
    func DoAThing() HowOdd {
    	return DoAConcreteThing()
    }
    
    func main() {
    	lolWhat := DoAThing()
    
    	if lolWhat != nil {
    		panic("How could this happen?")
    	}
    }
    

I understand that the interface at the bottom is a non-null interface containing a null value, but...damn, that sucks.