diff --git a/dvc/repo/index.py b/dvc/repo/index.py
index 8fbb18eee8..2f764a786d 100644
--- a/dvc/repo/index.py
+++ b/dvc/repo/index.py
@@ -359,7 +359,9 @@ def from_file(cls, repo: "Repo", path: str) -> "Index":
             params={path: dvcfile.params} if dvcfile.params else {},
             artifacts={path: dvcfile.artifacts} if dvcfile.artifacts else {},
             datasets={path: dvcfile.datasets} if dvcfile.datasets else {},
-            datasets_lock={path: dvcfile.datasets_lock} if dvcfile.datasets else {},
+            datasets_lock={path: dvcfile.datasets_lock}
+            if dvcfile.datasets_lock
+            else {},
         )
 
     def update(self, stages: Iterable["Stage"]) -> "Index":