From a915af9640527e706091d0bc6723aaf0864f88d3 Mon Sep 17 00:00:00 2001
From: Pavel Merzlyakov <panekmerzlyakov@gmail.com>
Date: Thu, 23 Nov 2023 21:42:04 +0300
Subject: [PATCH] fix reading null structs

---
 src/codegen.inc.php    | 9 +++++++++
 tpl/macros_struct.twig | 8 +++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/codegen.inc.php b/src/codegen.inc.php
index 7dbd1c7..0bef3e9 100644
--- a/src/codegen.inc.php
+++ b/src/codegen.inc.php
@@ -454,6 +454,7 @@ function default_value(\mtgMetaField $field)
   $type = $field->getType();
   $tokens = $field->getTokens();
   $default = $field->getToken('default');
+  $is_virtual = $field->hasToken('virtual');
 
   if($type instanceof \mtgBuiltinType) 
   {
@@ -476,6 +477,14 @@ function default_value(\mtgMetaField $field)
   } 
   else if($type instanceof \mtgMetaEnum)
     return $default ? go_type($type, $tokens)."_".trim($tokens['default'], '"') : 0;
+  else if($type instanceof \mtgMetaStruct)
+  {
+    if(!empty($default) && $default != 'null')
+    {
+      throw new Exception("not supported default value for struct '{$field->getName()}' with type '$type'");
+    }
+    return ($is_virtual ? '&' : '').go_type($type).'{}';
+  }
   else
     throw new Exception("Unknown type '$type'");
 }
diff --git a/tpl/macros_struct.twig b/tpl/macros_struct.twig
index 4800962..7d3435b 100644
--- a/tpl/macros_struct.twig
+++ b/tpl/macros_struct.twig
@@ -616,9 +616,15 @@ func (s *{{ name|default(s.name) }}) ReadFields(reader meta.Reader) error {
 			return err
 		}
 	} else {
-		if err := {{ fname }}.ReadFields(reader); err != nil {
+		size, err := reader.ContainerSize()
+		if err != nil {
 			return err
 		}
+		if size > 0 {
+			if err := {{ fname }}.ReadFields(reader); err != nil {
+				return err
+			}
+		}
 		if err := reader.EndContainer(); err != nil {
 			return err
 		}