source/blender/blenkernel/intern/node.cc

@@ -888,6 +888,29 @@ static void direct_link_node_socket_list(BlendDataReader *reader, ListBase *sock
   }
 }
 
+/* Build a set of built-in node types to check for known types. */
+static blender::Set<int> get_known_node_types_set()
+{
+  blender::Set<int> result;
+  NODE_TYPES_BEGIN (ntype) {
+    result.add(ntype->type);
+  }
+  NODE_TYPES_END;
+  return result;
+}
+
+static bool can_read_node_type(const int type)
+{
+  /* Can always read custom node types. */
+  if (type == NODE_CUSTOM) {
+    return true;
+  }
+
+  /* Check known built-in types. */
+  static blender::Set<int> known_types = get_known_node_types_set();
+  return known_types.contains(type);
+}
+
 void ntreeBlendReadData(BlendDataReader *reader, ID *owner_id, bNodeTree *ntree)
 {
   /* Special case for this pointer, do not rely on regular `lib_link` process here. Avoids needs
@@ -946,6 +969,18 @@ void ntreeBlendReadData(BlendDataReader *reader, ID *owner_id, bNodeTree *ntree)
     BLO_read_data_address(reader, &node->prop);
     IDP_BlendDataRead(reader, &node->prop);
 
+    /* Unknown built-in node types cannot be read reliably, so replace them with 'undefined' type
+     * nodes. This keeps links and socket names but discards storage an other type-specific data.
+     */
+    if (!can_read_node_type(node->type)) {
+      node->type = NODE_CUSTOM;
+      /* This type name is arbitrary, it just has to be unique enough to not match a future node
+       * idname. Includes the old type identifier for debugging purposes. */
+      const std::string old_idname = node->idname;
+      BLI_snprintf(node->idname, sizeof(node->idname), "Undefined[%s]", old_idname.c_str());
+      continue;
+    }
+
     if (node->type == CMP_NODE_MOVIEDISTORTION) {
       /* Do nothing, this is runtime cache and hence handled by generic code using
        * `IDTypeInfo.foreach_cache` callback. */