Send nice error when version number is out of range

main.go

@@ -138,6 +138,10 @@ func handler(resp http.ResponseWriter, req *http.Request) {
 	var ok bool
 	repo.Version, ok = parseVersion(m[3])
 	if !ok {
+		if repo.Version == TooHighVersion {
+			sendNotFound(resp, "Version %q contains a number which is out of range.", m[3])
+			return
+		}
 		sendNotFound(resp, "Version %q improperly considered invalid; please warn the service maintainers.", m[3])
 		return
 	}

version.go

@@ -48,6 +48,7 @@ func (v Version) IsValid() bool {
 }
 
 var InvalidVersion = Version{-1, -1, -1}
+var TooHighVersion = Version{-2, -2, -2}
 
 func parseVersion(s string) (Version, bool) {
 	if len(s) < 2 {
@@ -66,17 +67,20 @@ func parseVersion(s string) (Version, bool) {
 		if len(part) == 0 || part[0] == '0' {
 			return InvalidVersion, false
 		}
-		num, err := strconv.Atoi(part)
+		num, err := strconv.ParseInt(part, 10, 32)
 		if err != nil {
+			if err.(*strconv.NumError).Err == strconv.ErrRange {
+				return TooHighVersion, false
+			}
 			return InvalidVersion, false
 		}
 		switch i {
 		case 0:
-			v.Major = num
+			v.Major = int(num)
 		case 1:
-			v.Minor = num
+			v.Minor = int(num)
 		case 2:
-			v.Patch = num
+			v.Patch = int(num)
 		}
 	}