cmd: Strict unmarshal for validate (#5383)

caddy.go

@@ -314,7 +314,7 @@ func unsyncedDecodeAndRun(cfgJSON []byte, allowPersist bool) error {
 	strippedCfgJSON := RemoveMetaFields(cfgJSON)
 
 	var newCfg *Config
-	err := strictUnmarshalJSON(strippedCfgJSON, &newCfg)
+	err := StrictUnmarshalJSON(strippedCfgJSON, &newCfg)
 	if err != nil {
 		return err
 	}

cmd/commandfuncs.go

@@ -490,7 +490,7 @@ func cmdAdaptConfig(fl Flags) (int, error) {
 	// validate output if requested
 	if adaptCmdValidateFlag {
 		var cfg *caddy.Config
-		err = json.Unmarshal(adaptedConfig, &cfg)
+		err = caddy.StrictUnmarshalJSON(adaptedConfig, &cfg)
 		if err != nil {
 			return caddy.ExitCodeFailedStartup, fmt.Errorf("decoding config: %v", err)
 		}
@@ -523,7 +523,7 @@ func cmdValidateConfig(fl Flags) (int, error) {
 	input = caddy.RemoveMetaFields(input)
 
 	var cfg *caddy.Config
-	err = json.Unmarshal(input, &cfg)
+	err = caddy.StrictUnmarshalJSON(input, &cfg)
 	if err != nil {
 		return caddy.ExitCodeFailedStartup, fmt.Errorf("decoding config: %v", err)
 	}

context.go

@@ -326,7 +326,7 @@ func (ctx Context) LoadModuleByID(id string, rawMsg json.RawMessage) (any, error
 
 	// fill in its config only if there is a config to fill in
 	if len(rawMsg) > 0 {
-		err := strictUnmarshalJSON(rawMsg, &val)
+		err := StrictUnmarshalJSON(rawMsg, &val)
 		if err != nil {
 			return nil, fmt.Errorf("decoding module config: %s: %v", modInfo, err)
 		}

modules.go

@@ -333,11 +333,11 @@ func ParseStructTag(tag string) (map[string]string, error) {
 	return results, nil
 }
 
-// strictUnmarshalJSON is like json.Unmarshal but returns an error
+// StrictUnmarshalJSON is like json.Unmarshal but returns an error
 // if any of the fields are unrecognized. Useful when decoding
 // module configurations, where you want to be more sure they're
 // correct.
-func strictUnmarshalJSON(data []byte, v any) error {
+func StrictUnmarshalJSON(data []byte, v any) error {
 	dec := json.NewDecoder(bytes.NewReader(data))
 	dec.DisallowUnknownFields()
 	return dec.Decode(v)