diff --git a/swh/loader/svn/converters.py b/swh/loader/svn/converters.py
--- a/swh/loader/svn/converters.py
+++ b/swh/loader/svn/converters.py
@@ -80,5 +80,5 @@
         committer=author,
         synthetic=True,
         metadata=metadata,
-        parents=parents,
+        parents=tuple(parents),
     )
diff --git a/swh/loader/svn/tests/test_converters.py b/swh/loader/svn/tests/test_converters.py
--- a/swh/loader/svn/tests/test_converters.py
+++ b/swh/loader/svn/tests/test_converters.py
@@ -62,7 +62,7 @@
             "author_date": date,
         },
         rev=10,
-        parents=[],
+        parents=(),
     )
 
     expected_rev = Revision.from_dict(
@@ -86,7 +86,7 @@
             "metadata": {
                 "extra_headers": [["svn_repo_uuid", b"uuid"], ["svn_revision", b"10"],]
             },
-            "parents": [],
+            "parents": (),
         }
     )