Use url.Parse to parse hostname (#12335)

modules/setting/setting.go

@@ -626,11 +626,8 @@ func NewContext() {
 	StaticURLPrefix = strings.TrimSuffix(sec.Key("STATIC_URL_PREFIX").MustString(AppSubURL), "/")
 	AppSubURLDepth = strings.Count(AppSubURL, "/")
 	// Check if Domain differs from AppURL domain than update it to AppURL's domain
-	urlHostname, _, err := net.SplitHostPort(appURL.Host)
-	if err != nil {
-		log.Fatal("Invalid host in ROOT_URL '%s': %s", appURL.Host, err)
-	}
-	if urlHostname != Domain && net.ParseIP(urlHostname) == nil {
+	urlHostname := appURL.Hostname()
+	if urlHostname != Domain && net.ParseIP(urlHostname) == nil && urlHostname != "" {
 		Domain = urlHostname
 	}