table revision number

common/proto/table_structure.proto

@@ -143,6 +143,8 @@ message GetTableImportDescriptorResponse {
   string storage_profile_name = 2;
   string table_name = 3;
   int64 table_id = 4;
+  // Version of this import contract. Send it as expected_table_revision on
+  // every staged chunk so schema/rule changes refuse stale prepared data.
   int64 table_revision = 5;
   repeated ImportFieldDescriptor fields = 6;
 }