all: use semver to compare versions (#6147)

internal/semverutil/semverutil.go

@@ -0,0 +1,37 @@
+// Copyright 2020 The Gogs Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package semverutil
+
+import (
+	"strings"
+
+	"github.com/Masterminds/semver/v3"
+)
+
+// Compare returns true if the comparison is true for given versions. It returns false if
+// comparison is false, or failed to parse one or both versions as Semantic Versions.
+//
+// See https://github.com/Masterminds/semver#basic-comparisons for supported comparisons.
+func Compare(version1, comparison, version2 string) bool {
+	clean := func(v string) string {
+		if strings.Count(v, ".") > 2 {
+			fields := strings.SplitN(v, ".", 4)
+			v = strings.Join(fields[:3], ".")
+		}
+		return v
+	}
+
+	v, err := semver.NewVersion(clean(version1))
+	if err != nil {
+		return false
+	}
+
+	c, err := semver.NewConstraint(comparison + " " + clean(version2))
+	if err != nil {
+		return false
+	}
+
+	return c.Check(v)
+}