Semver sort

February 12, 2023

Name: Moch Lutfi
Twitter: @kaptenupi

Problem

given input array of string contains release version that must follow x.y.z form.
x.y.z must be integer with positive values
sort by latest release

Solution

See in playground https://go.dev/play/p/_nFWNUOcDCu (opens in a new tab).

The process is straigtforward

Parse string into semver struct
Sort using custom slice and implement required sorting interface Len, Swap and Less, refers to https://pkg.go.dev/sort#example-package (opens in a new tab)
Revert back to array of string where version string follows x.y.z format

package main
import (
	"fmt"
	"sort"
	"strconv"
	"strings"
)
// Semver represents a semantic version in the format x.y.z
type Semver struct {
	Major int
	Minor int
	Patch int
}
func (s Semver) ToString() string {
	return fmt.Sprintf("%d.%d.%d", s.Major, s.Minor, s.Patch)
}
// NewSemver returns a new Semver instance with the specified major, minor, and patch values.
func NewSemver(major int, minor int, patch int) Semver {
	return Semver{
		Major: major,
		Minor: minor,
		Patch: patch,
	}
}
// ParseSemver takes a string representation of a semantic version in the format x.y.z and returns a new Semver instance.
func ParseSemver(version string) (Semver, error) {
	parts := strings.Split(version, ".")
	if len(parts) != 3 {
		return Semver{}, fmt.Errorf("invalid version format: %s", version)
	}
	major, minor, patch := 0, 0, 0
	var err error
	if major, err = strconv.Atoi(parts[0]); err != nil || major < 0 {
		return Semver{}, fmt.Errorf("invalid major version: %s", parts[0])
	}
	if minor, err = strconv.Atoi(parts[1]); err != nil || minor < 0 {
		return Semver{}, fmt.Errorf("invalid minor version: %s", parts[1])
	}
	if patch, err = strconv.Atoi(parts[2]); err != nil || patch < 0 {
		return Semver{}, fmt.Errorf("invalid patch version: %s", parts[2])
	}
	return NewSemver(major, minor, patch), nil
}
// Versions is a slice of Semver instances
type Versions []Semver
func (v Versions) Len() int {
	return len(v)
}
func (v Versions) Less(i, j int) bool {
	if v[i].Major != v[j].Major {
		return v[i].Major < v[j].Major
	}
	if v[i].Minor != v[j].Minor {
		return v[i].Minor < v[j].Minor
	}
	return v[i].Patch < v[j].Patch
}
func (v Versions) Swap(i, j int) {
	v[i], v[j] = v[j], v[i]
}
func solution(input []string) []string {
	var versions Versions
	for _, v := range input {
		semver, err := ParseSemver(v)
		if err == nil {
			versions = append(versions, semver)
		}
	}
	sort.Sort(sort.Reverse(versions))
	result := []string{}
	for _, v := range versions {
		result = append(result, v.ToString())
	}
	return result
}
func main() {
	input := []string{"1.0.0", "2.0.0", "0.1.0", "3.0.0", "invalid", "1.2.3", "1.2.3-rc", "1.-1.2"}
	result := solution(input)
	fmt.Println(result)
}

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