config.ParseFlags(): enforce type constraints via generics, not reflection

Author: Al2Klimov

config/config.go

@@ -8,7 +8,6 @@ import (
 	"github.com/jessevdk/go-flags"
 	"github.com/pkg/errors"
 	"os"
-	"reflect"
 )
 
 // ErrInvalidArgument is the error returned by [ParseFlags] or [FromYAMLFile] if
@@ -58,10 +57,9 @@ func FromYAMLFile[T any, V validatorPtr[T]](name string, v V) error {
 // ParseFlags prints the help message to [os.Stdout] and exits.
 // Note that errors are not printed automatically,
 // so error handling is the sole responsibility of the caller.
-func ParseFlags(v any) error {
-	rv := reflect.ValueOf(v)
-	if rv.Kind() != reflect.Pointer || rv.IsNil() {
-		return errors.Wrapf(ErrInvalidArgument, "non-nil pointer expected, got %T", v)
+func ParseFlags[T any](v *T) error {
+	if v == nil {
+		return errors.Wrap(ErrInvalidArgument, "got nil pointer")
 	}
 
 	parser := flags.NewParser(v, flags.Default^flags.PrintErrors)