1 files changed, 5 insertions, 0 deletions
diff --git a/python/google/protobuf/text_format.py b/python/google/protobuf/text_format.py
index 1cddce6c..889aa836 100755
--- a/python/google/protobuf/text_format.py
+++ b/python/google/protobuf/text_format.py
@@ -149,6 +149,10 @@ def _MergeField(tokenizer, message):
       name.append(tokenizer.ConsumeIdentifier())
     name = '.'.join(name)
 
+    if not message_descriptor.is_extendable:
+      raise tokenizer.ParseErrorPreviousToken(
+          'Message type "%s" does not have extensions.' %
+          message_descriptor.full_name)
     field = message.Extensions._FindExtensionByName(name)
     if not field:
       raise tokenizer.ParseErrorPreviousToken(
@@ -198,6 +202,7 @@ def _MergeField(tokenizer, message):
         sub_message = message.Extensions[field]
       else:
         sub_message = getattr(message, field.name)
+        sub_message.SetInParent()
 
     while not tokenizer.TryConsume(end_token):
       if tokenizer.AtEnd():