error out if invalid flag combination has been set

cmd/manager/main.go

@@ -62,6 +62,12 @@ func main() {
 	flag.CommandLine.AddGoFlagSet(logFlags)
 	flag.Parse()
 
+	err = farosflags.ValidateSettings()
+	if err != nil {
+		log.Error(err, "Invalid flags set")
+		return
+	}
+
 	// Handle version flag
 	if *showVersion {
 		fmt.Printf("faros-gittrack-controller %s (built with %s)\n", VERSION, runtime.Version())

pkg/flags/flagset.go

@@ -87,6 +87,19 @@ func ParseIgnoredResources() (map[schema.GroupVersionResource]interface{}, error
 	return gvrs, nil
 }
 
+// ValidateSettings returns an error if an invalid set of options have been set in the flags.
+// It must be called after the flags have been parsed
+func ValidateSettings() error {
+	if !FlagSet.Parsed() {
+		return fmt.Errorf("ValidateSettings called on unparsed flags")
+	}
+
+	if GitTrack == GTMEnabled && Namespace != "" && ClusterGitTrack == CGTMIncludeNamespaced {
+		return fmt.Errorf("Cannot use gittrack-mode enabled with namespace %q and clustergittrack-mode set to IncludeNamespaced", Namespace)
+	}
+	return nil
+}
+
 // ClusterGitTrackMode specifies which mode we're running ClusterGitTracks in
 type ClusterGitTrackMode int