From 944a052af8ae90cd1afd74d95d7b66a2f8e3f767 Mon Sep 17 00:00:00 2001
From: unbyte <i@shangyes.net>
Date: Sat, 6 Nov 2021 15:02:36 +0800
Subject: [PATCH] fix(update): correct semver comparison behaviour

---
 pkg/handler/update.go    | 29 +-------------
 pkg/utils/semver.go      | 84 ++++++++++++++++++++++++++++++++++++++++
 pkg/utils/semver_test.go | 57 +++++++++++++++++++++++++++
 3 files changed, 142 insertions(+), 28 deletions(-)
 create mode 100644 pkg/utils/semver.go
 create mode 100644 pkg/utils/semver_test.go

diff --git a/pkg/handler/update.go b/pkg/handler/update.go
index 9e2491b..1a4ab2f 100644
--- a/pkg/handler/update.go
+++ b/pkg/handler/update.go
@@ -12,8 +12,6 @@ import (
 	"path/filepath"
 	"regexp"
 	"runtime"
-	"strconv"
-	"strings"
 	"time"
 )
 
@@ -40,31 +38,6 @@ func NewUpdateHandler() *UpdateHandler {
 	}
 }
 
-// compareVersion compares strings like "v1.1.1", returns true when versionA > versionB
-func (u *UpdateHandler) compareVersion(versionA, versionB string) bool {
-	if versionA == "" {
-		return false
-	}
-	if versionB == "" {
-		return true
-	}
-	aList := strings.Split(versionA[1:], ".")
-	bList := strings.Split(versionB[1:], ".")
-	aLen := len(aList)
-	bLen := len(bList)
-	if aLen != bLen {
-		return aLen > bLen
-	}
-	for i := 0; i < aLen; i++ {
-		a, _ := strconv.Atoi(aList[i])
-		b, _ := strconv.Atoi(bList[i])
-		if a > b {
-			return true
-		}
-	}
-	return false
-}
-
 // CheckLatestVersion returns true when there is a newer version
 func (u *UpdateHandler) CheckLatestVersion() (bool, error) {
 	resp, err := u.client.Get(fmt.Sprintf("https://api.github.com/repos/%s/releases/latest", ipgw.Repo))
@@ -73,7 +46,7 @@ func (u *UpdateHandler) CheckLatestVersion() (bool, error) {
 	}
 	body := utils.ReadBody(resp)
 	latestVersion, _ := utils.MatchSingle(regexp.MustCompile(`"tag_name": *"(.+?)"`), body)
-	return u.compareVersion(latestVersion, ipgw.Version), nil
+	return utils.CompareVersion(utils.ParseVersion(latestVersion), utils.ParseVersion(ipgw.Version)), nil
 }
 
 // download returns downloaded path
diff --git a/pkg/utils/semver.go b/pkg/utils/semver.go
new file mode 100644
index 0000000..c554ce9
--- /dev/null
+++ b/pkg/utils/semver.go
@@ -0,0 +1,84 @@
+package utils
+
+import (
+	"strconv"
+	"strings"
+)
+
+type Semver struct {
+	Major      int
+	Minor      int
+	Patch      int
+	Prerelease string
+}
+
+// CompareVersion compares strings like "v1.1.1", returns true when versionA > versionB
+func CompareVersion(versionA, versionB *Semver) bool {
+	if versionA == nil {
+		return false
+	}
+	if versionB == nil {
+		return true
+	}
+	// semver:
+	//   v1.0.1 > v1.0.0
+	//   v1.0.0 > v1.0.0-beta
+	//   v1.0.0-beta.1 > v1.0.0-beta
+	//   v1.0.0-beta > v1.0.0-alpha
+	if versionA.Major != versionB.Major {
+		return versionA.Major > versionB.Major
+	}
+
+	if versionA.Minor != versionB.Minor {
+		return versionA.Minor > versionB.Minor
+	}
+
+	if versionA.Patch != versionB.Patch {
+		return versionA.Patch > versionB.Patch
+	}
+
+	if versionA.Prerelease != "" && versionB.Prerelease != "" {
+		return versionA.Prerelease > versionB.Prerelease
+	}
+
+	if versionA.Prerelease != "" {
+		// versionB.Prerelease == ""
+		return false
+	}
+
+	if versionB.Prerelease != "" {
+		// versionA.Prerelease == ""
+		return true
+	}
+
+	return false
+}
+
+func ParseVersion(version string) *Semver {
+	if version == "" {
+		return nil
+	}
+	// remove leading 'v'
+	version = strings.TrimPrefix(version, "v")
+	parts := strings.Split(version, "-")
+	if len(parts) < 1 {
+		return nil
+	}
+	dot := strings.Split(parts[0], ".")
+	if len(dot) < 3 {
+		return nil
+	}
+	preRelease := ""
+	if len(parts) > 1 {
+		preRelease = parts[1]
+	}
+	major, _ := strconv.Atoi(dot[0])
+	minor, _ := strconv.Atoi(dot[1])
+	patch, _ := strconv.Atoi(dot[2])
+	return &Semver{
+		Major:      major,
+		Minor:      minor,
+		Patch:      patch,
+		Prerelease: preRelease,
+	}
+}
diff --git a/pkg/utils/semver_test.go b/pkg/utils/semver_test.go
new file mode 100644
index 0000000..159f902
--- /dev/null
+++ b/pkg/utils/semver_test.go
@@ -0,0 +1,57 @@
+package utils
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestParseVersion(t *testing.T) {
+	a := assert.New(t)
+	cases := []struct {
+		v      string
+		parsed *Semver
+	}{
+		{v: "v1.0.1", parsed: &Semver{
+			Major:      1,
+			Minor:      0,
+			Patch:      1,
+			Prerelease: "",
+		}},
+		{v: "v1.0.1-beta", parsed: &Semver{
+			Major:      1,
+			Minor:      0,
+			Patch:      1,
+			Prerelease: "beta",
+		}},
+		{v: "0.2.0-alpha.3", parsed: &Semver{
+			Major:      0,
+			Minor:      2,
+			Patch:      0,
+			Prerelease: "alpha.3",
+		}},
+		{v: "0.1", parsed: nil},
+	}
+	for _, c := range cases {
+		a.Equal(ParseVersion(c.v), c.parsed)
+	}
+}
+
+func TestCompareVersion(t *testing.T) {
+	a := assert.New(t)
+	cases := []struct {
+		a        string
+		b        string
+		expected bool
+	}{
+		{a: "v1.0.0", b: "v0.2.2", expected: true},
+		{a: "v1.0.0-alpha", b: "v1.2.2", expected: false},
+		{a: "v1.0.0-alpha", b: "v1.0.0", expected: false},
+		{a: "v1.0.0", b: "v1.0.0-beta.2", expected: true},
+		{a: "v1.0.0-beta", b: "v1.0.0-alpha", expected: true},
+		{a: "v1", b: "v1.0.0-alpha", expected: false},
+		{a: "1.0.0-beta", b: "", expected: true},
+	}
+	for _, c := range cases {
+		a.Equal(CompareVersion(ParseVersion(c.a), ParseVersion(c.b)), c.expected)
+	}
+}