--- a/taskcluster/taskgraph/files_changed.py
+++ b/taskcluster/taskgraph/files_changed.py
@@ -52,17 +52,17 @@ def check(params, file_patterns):
     revision = params.get('head_rev')
     if not repository or not revision:
         logger.warning("Missing `head_repository` or `head_rev` parameters; "
                        "assuming all files have changed")
         return True
 
     changed_files = get_changed_files(repository, revision)
 
-    if 'comm_repository' in params:
+    if 'comm_head_repository' in params:
         repository = params.get('comm_head_repository')
         revision = params.get('comm_head_rev')
         if not revision:
             logger.warning("Missing `comm_head_rev` parameters; "
                            "assuming all files have changed")
             return True
 
         changed_files |= {