From 272534584376c81116db5199fd2e4216e3698192 Mon Sep 17 00:00:00 2001
From: Runxi Yu <me@runxiyu.org>
Date: Sat, 05 Apr 2025 22:22:46 +0800
Subject: [PATCH] scfg: Error out when required directives are missing

---
 config.go                  |  2 --
 internal/scfg/unmarshal.go | 14 ++++++++++++++

diff --git a/config.go b/config.go
index 21587210a505b3ea3267b7e6d2478151dfb42db2..abb71dd2b2beacdb5dd194b0957e331661756f72 100644
--- a/config.go
+++ b/config.go
@@ -69,8 +69,6 @@ // LoadConfig loads a configuration file from the specified path and unmarshals
 // 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 19f3dae73a775b5be26e850db350d015d160ddc0..e9e1a528a0700ab641b304f12169c4b07d92ff96 100644
--- a/internal/scfg/unmarshal.go
+++ b/internal/scfg/unmarshal.go
@@ -107,11 +107,14 @@ 				return err
 			}
 			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]
@@ -123,7 +126,18 @@ 			fv := v.Field(fieldIndex)
 			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)
 	}

-- 
2.48.1