scfg: Error out when required directives are missingv0.1.25

2 files changed, 14 insertions, 2 deletions

diff --git a/config.go b/config.go
index 2158721..abb71dd 100644
--- a/config.go
+++ b/config.go
@@ -69,8 +69,6 @@ type Config struct {
 // it to the global [config] struct. This may race with concurrent reads from
 // [config]; additional synchronization is necessary if the configuration is to
 // be made reloadable.
-//
-// TODO: Error out when there are missing fields
 func (s *Server) LoadConfig(path string) (err error) {
 	var configFile *os.File
 	if configFile, err = os.Open(path); err != nil {
diff --git a/internal/scfg/unmarshal.go b/internal/scfg/unmarshal.go
index 19f3dae..e9e1a52 100644
--- a/internal/scfg/unmarshal.go
+++ b/internal/scfg/unmarshal.go
@@ -107,12 +107,15 @@ func (dec *Decoder) unmarshalBlock(block Block, v reflect.Value) error {
 			}
 			v.SetMapIndex(reflect.ValueOf(name), mv)
 		}
+
 	case reflect.Struct:
 		si, err := getStructInfo(t)
 		if err != nil {
 			return err
 		}
 
+		seen := make(map[int]bool)
+
 		for name, dirs := range dirsByName {
 			fieldIndex, ok := si.children[name]
 			if !ok {
@@ -123,7 +126,18 @@ func (dec *Decoder) unmarshalBlock(block Block, v reflect.Value) error {
 			if err := dec.unmarshalDirectiveList(dirs, fv); err != nil {
 				return err
 			}
+			seen[fieldIndex] = true
+		}
+
+		for name, fieldIndex := range si.children {
+			if fieldIndex == si.param {
+				continue
+			}
+			if _, ok := seen[fieldIndex]; !ok {
+				return fmt.Errorf("scfg: missing required directive %q", name)
+			}
 		}
+
 	default:
 		return fmt.Errorf("scfg: unsupported type for unmarshaling blocks: %v", t)
 	}