mathutil.Max bug

[feeops]

// Max return max value of numbers.
// Play: https://go.dev/play/p/cN8DHI0rTkH
func Max[T constraints.Integer | constraints.Float](numbers ...T) T {
	max := numbers[0]

	for _, v := range numbers {
		if max < v {
			max = v
		}
	}

	return max
}

if numbers is empty,it will panic

[cannian1]

If we follow the function signature of the standard library 1.21+, func max[T cmp.Ordered](x T, y ...T) T
this will break backward compatibility.

Should we change it this way? Or would it be more elegant to throw a panic when the number of arguments passed is zero? @duke-git

[duke-git]

If we follow the function signature of the standard library 1.21+, func max[T cmp.Ordered](x T, y ...T) T this will break backward compatibility.

Should we change it this way? Or would it be more elegant to throw a panic when the number of arguments passed is zero? @duke-git

@cannian1, There is no more elegant way to solve this problem, we can choose one of the following 4 methods. Each one has its drawbacks. I prefer the option 4 (last one).

1. Return the zero value, when the number of arguments passed is zero. (drawback: this can't tell the difference of params case like: []int{}, []int{0,0,0})

func Max[T constraints.Integer | constraints.Float](numbers ...T) T {
	if len(numbers) == 0 {
		var zero T
		return zero
	}

	max := numbers[0]

	for _, v := range numbers {
		if max < v {
			max = v
		}
	}

	return max
}

2. Follow the function signature of the standard library 1.21+, func max[T cmp.Ordered](x T, y ...T) T, this will break backward compatibility.

3. Return an error if the slice is empty. this will also break backward compatibility.

func Max[T constraints.Integer | constraints.Float](numbers ...T) (T, error) {
    if len(numbers) == 0 {
        var zero T
        return zero, fmt.Errorf("no numbers")
    }

    max := numbers[0]
    for _, v := range numbers {
        if max < v {
            max = v
        }
    }

    return max, nil
}

4. Throw a panic info when the number of arguments passed is zero. This is also the way of slices std package. (slices.Max Although its param type is slice)

func Max[T constraints.Integer | constraints.Float](numbers ...T) T {
	if len(numbers) == 0 {
		panic("mathutil.Max: empty numbers")
	}

	max := numbers[0]

	for _, v := range numbers {
		if max < v {
			max = v
		}
	}

	return max
}