Capture immutable command declarations

registry.go

@@ -14,13 +14,17 @@ func (a *App) Register(commands ...Command) error {
 		if err := validateCommandDeclaration(command); err != nil {
 			return err
 		}
-		if _, exists := a.commands[command.name]; exists {
-			return fmt.Errorf("command path %q is already registered", command.name)
+		if command.record.absent {
+			continue
 		}
-		if _, exists := pending[command.name]; exists {
-			return fmt.Errorf("command path %q is already registered", command.name)
+		name := command.record.name
+		if _, exists := a.commands[name]; exists {
+			return fmt.Errorf("command path %q is already registered", name)
 		}
-		pending[command.name] = &commandNode{command: cloneCommand(command)}
+		if _, exists := pending[name]; exists {
+			return fmt.Errorf("command path %q is already registered", name)
+		}
+		pending[name] = &commandNode{command: command}
 	}
 	if len(pending) == 0 {
 		return nil