From 7b76d94c5b167e13278c660e647dbd712c4b626f Mon Sep 17 00:00:00 2001
From: Alexandre Edmond <145270396+AlexandreEDMOND@users.noreply.github.com>
Date: Tue, 28 Jul 2026 16:25:42 +0200
Subject: [PATCH] Handle resuming empty local datasets (#3859)

Co-authored-by: Steven Palma <imstevenpmwork@ieee.org>
---
 src/lerobot/datasets/dataset_metadata.py |  4 ++--
 tests/datasets/test_lerobot_dataset.py   | 14 ++++++++++++++
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/lerobot/datasets/dataset_metadata.py b/src/lerobot/datasets/dataset_metadata.py
index ed5e13833..1f0e0add9 100644
--- a/src/lerobot/datasets/dataset_metadata.py
+++ b/src/lerobot/datasets/dataset_metadata.py
@@ -188,8 +188,8 @@ class LeRobotDatasetMetadata:
     def _load_metadata(self):
         self.info = load_info(self.root)
         check_version_compatibility(self.repo_id, self._version, CODEBASE_VERSION)
-        self.tasks = load_tasks(self.root)
-        self.episodes = load_episodes(self.root)
+        self.tasks = load_tasks(self.root) if self.total_tasks > 0 else None
+        self.episodes = load_episodes(self.root) if self.total_episodes > 0 else None
         self.stats = load_stats(self.root)
 
     def ensure_readable(self) -> None:
diff --git a/tests/datasets/test_lerobot_dataset.py b/tests/datasets/test_lerobot_dataset.py
index f1614de52..4d12fc4aa 100644
--- a/tests/datasets/test_lerobot_dataset.py
+++ b/tests/datasets/test_lerobot_dataset.py
@@ -482,6 +482,20 @@ def test_add_frame_works_in_write_mode(tmp_path):
 # ── Resume mode ──────────────────────────────────────────────────────
 
 
+def test_resume_freshly_created_empty_dataset(tmp_path):
+    """resume() accepts a local dataset created before any episode was recorded."""
+    root = tmp_path / "resume_empty_ds"
+    LeRobotDataset.create(repo_id=DUMMY_REPO_ID, fps=DEFAULT_FPS, features=SIMPLE_FEATURES, root=root)
+
+    resumed = LeRobotDataset.resume(repo_id=DUMMY_REPO_ID, root=root)
+
+    assert isinstance(resumed.writer, DatasetWriter)
+    assert resumed.meta.total_episodes == 0
+    assert resumed.meta.total_frames == 0
+    assert resumed.meta.tasks is None
+    assert resumed.meta.episodes is None
+
+
 def test_resume_creates_writer(tmp_path):
     """After resume(), writer is a DatasetWriter."""
     root = tmp_path / "resume_ds"