fix: solved error on Protobuf messages with oneof fields

Author: ralvarezdev

mapper/constants.go

@@ -7,6 +7,7 @@ const (
 	UnknownFields      = "unknownFields"
 	ProtobufTag        = "protobuf"
 	ProtobufOneOf      = "oneof"
+	ProtobufOneOfTag   = "protobuf_oneof"
 	ProtobufNamePrefix = "name="
 	JSONTag            = "json"
 	JSONOmitempty      = "omitempty"

mapper/protobuf.go

@@ -73,6 +73,11 @@ func (p ProtobufGenerator) NewMapper(structInstance any) (
 		if IsProtobufGeneratedField(fieldName) {
 			continue
 		}
+		
+		// Omit protobuf oneof field (optional fields)
+		if IsProtobufOneOfField(structField) {
+			continue
+		}
 
 		// Get the Protobuf tag of the field
 		protobufTag, err := GetProtobufTag(structField, fieldName)
@@ -124,23 +129,6 @@ func (p ProtobufGenerator) NewMapper(structInstance any) (
 			rootMapper.AddFieldNestedMapper(fieldName, fieldNestedMapper)
 		}
 
-		// Check if the field is an interface (special case for oneof fields)
-		if fieldType.Kind() == reflect.Interface {
-			// Set field as not required
-			rootMapper.SetFieldIsRequired(fieldName, false)
-
-			// Print field
-			DetectedField(
-				structTypeName,
-				fieldName,
-				fieldType,
-				protobufTag,
-				false,
-				p.logger,
-			)
-			continue
-		}
-
 		// Set field as required
 		rootMapper.SetFieldIsRequired(fieldName, true)
 

mapper/utils.go

@@ -51,14 +51,26 @@ func GetJSONTagName(jsonTag, fieldName string) (string, error) {
 // - string: Protobuf tag
 // - error: error if the Protobuf tag is not found
 func GetProtobufTag(structField reflect.StructField, fieldName string) (string, error) {
-	// Get the Protobuf tag of the field
 	protobufTag := structField.Tag.Get(ProtobufTag)
 	if protobufTag == "" {
 		return "", fmt.Errorf(ErrProtobufTagNotFound, fieldName)
 	}
 	return protobufTag, nil
 }
 
+// IsProtobufOneOfField checks if the struct field is a Protobuf oneof field
+// 
+// Parameters:
+// 
+// - structField: The struct field
+// 
+// Returns:
+// 
+// - bool: true if the struct field is a Protobuf oneof field
+func IsProtobufOneOfField(structField reflect.StructField) bool {
+	return structField.Tag.Get(ProtobufOneOfTag) != ""
+}
+
 // GetProtobufTagName returns the Protobuf tag name for a given struct field name
 //
 // Parameters: