Fix: content-type of zero is also invalid (#26)

Author: TrueBrain

openttd_protocol/protocol/content.py

@@ -87,7 +87,7 @@ def receive_PACKET_CONTENT_CLIENT_INFO_LIST(source, data):
                 version, data = read_string(data)
                 branch_versions[branch] = version
 
-        if content_type >= ContentType.CONTENT_TYPE_END:
+        if content_type == 0 or content_type >= ContentType.CONTENT_TYPE_END:
             raise PacketInvalidData("invalid ContentType", content_type)
 
         content_type = ContentType(content_type)
@@ -109,7 +109,7 @@ def _receive_client_info(data, count, has_content_id=False, has_content_type_and
 
             if has_content_type_and_unique_id:
                 content_type, data = read_uint8(data)
-                if content_type >= ContentType.CONTENT_TYPE_END:
+                if content_type == 0 or content_type >= ContentType.CONTENT_TYPE_END:
                     raise PacketInvalidData("invalid ContentType", content_type)
                 content_type = ContentType(content_type)
                 content_info["content_type"] = content_type