feat: add retry functionality for failed downloads

app/tests/test_api.py

@@ -20,6 +20,7 @@ def mock_dqueue(monkeypatch):
     d = MagicMock()
     d.initialize = AsyncMock(return_value=None)
     d.add = AsyncMock(return_value={"status": "ok"})
+    d.retry = AsyncMock(return_value={"status": "ok"})
     d.cancel = AsyncMock(return_value={"status": "ok"})
     d.clear = AsyncMock(return_value={"status": "ok"})
     d.start_pending = AsyncMock(return_value={"status": "ok"})
@@ -69,6 +70,14 @@ async def test_add_ok(mock_dqueue):
     mock_dqueue.add.assert_awaited_once()
 
 
+@pytest.mark.asyncio
+async def test_retry_passes_failed_download_id(mock_dqueue):
+    req = _json_request({"ids": ["https://example.com/watch?v=1"]})
+    resp = await main.retry(req)
+    assert resp.status == 200
+    mock_dqueue.retry.assert_awaited_once_with("https://example.com/watch?v=1")
+
+
 @pytest.mark.asyncio
 async def test_add_passes_preset_and_overrides(mock_dqueue, monkeypatch):
     monkeypatch.setattr(main.config, "YTDL_OPTIONS_PRESETS", {"Preset A": {"writesubtitles": True}})

app/tests/test_download_queue.py

@@ -302,6 +302,55 @@ async def test_add_entry_queues_single_video_without_reextracting(dq_env):
     assert dq.pending.exists("https://example.com/watch?v=1")
 
 
+@pytest.mark.asyncio
+async def test_retry_restores_playlist_output_context(dq_env):
+    notifier = AsyncMock()
+    dq_env.OUTPUT_TEMPLATE_PLAYLIST = "%(playlist_title)s/%(title)s.%(ext)s"
+    dq = DownloadQueue(dq_env, notifier)
+    url = "https://example.com/watch?v=1"
+    failed_info = DownloadInfo(
+        id="vid1",
+        title="Test Video",
+        url=url,
+        quality="best",
+        download_type="video",
+        codec="auto",
+        format="any",
+        folder="",
+        custom_name_prefix="",
+        error="temporary failure",
+        entry={
+            "playlist_index": "01",
+            "playlist_title": "My Playlist",
+            "playlist_count": 10,
+        },
+        playlist_item_limit=0,
+        split_by_chapters=False,
+        chapter_template="",
+    )
+    failed_info.status = "error"
+    dq.done.put(Download(None, None, None, None, "best", "any", {}, failed_info))
+
+    def fake_extract(self, extracted_url, ytdl_options_presets=None, ytdl_options_overrides=None):
+        return {
+            "_type": "video",
+            "id": "vid1",
+            "title": "Test Video",
+            "url": extracted_url,
+            "webpage_url": extracted_url,
+        }
+
+    with patch.object(DownloadQueue, "_DownloadQueue__extract_info", fake_extract), \
+         patch.object(DownloadQueue, "_DownloadQueue__start_download", new=AsyncMock()):
+        result = await dq.retry(url)
+
+    assert result["status"] == "ok"
+    queued = dq.queue.get(url)
+    assert queued.output_template == "My Playlist/%(title)s.%(ext)s"
+    assert queued.info.entry["playlist_index"] == "01"
+    assert queued.info.entry["playlist_title"] == "My Playlist"
+
+
 @pytest.mark.asyncio
 async def test_add_entry_duplicate_while_pending_is_skipped_not_clobbered(dq_env):
     notifier = AsyncMock()

app/tests/test_persistent_queue.py

@@ -146,12 +146,12 @@ class PersistentQueueTests(unittest.TestCase):
             self.assertNotIn("formats", record["entry"])
             self.assertNotIn("description", record["entry"])
 
-    def test_completed_queue_does_not_persist_entry_or_transient_progress(self):
+    def test_completed_queue_persists_only_failed_retry_context(self):
         with tempfile.TemporaryDirectory() as tmp:
             path = os.path.join(tmp, "completed")
             pq = PersistentQueue("completed", path)
             info = _make_info("http://done.example")
-            info.status = "finished"
+            info.status = "error"
             info.percent = 88
             info.speed = 123
             info.eta = 9
@@ -167,12 +167,24 @@ class PersistentQueueTests(unittest.TestCase):
                 payload = json.load(f)
 
             record = payload["items"][0]["info"]
-            self.assertNotIn("entry", record)
+            self.assertEqual(
+                record["entry"],
+                {
+                    "playlist_index": "01",
+                    "playlist_title": "Playlist",
+                },
+            )
             self.assertNotIn("percent", record)
             self.assertNotIn("speed", record)
             self.assertNotIn("eta", record)
             self.assertEqual(record["filename"], "done.mp4")
 
+            info.status = "finished"
+            pq.put(_FakeDownload(info))
+            with open(path + ".json", encoding="utf-8") as f:
+                payload = json.load(f)
+            self.assertNotIn("entry", payload["items"][0]["info"])
+
     def test_invalid_json_is_quarantined_and_legacy_is_imported(self):
         with tempfile.TemporaryDirectory() as tmp:
             path = os.path.join(tmp, "queue")