{"record":{"id":"44483ab81957e535","repo":"facebookresearch/detectron2","slug":"no-built-in-metadata-for-dataset-44483a","errorCode":null,"errorMessage":"No built-in metadata for dataset {}","messagePattern":"No built-in metadata for dataset (.+?)","errorType":"exception","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"detectron2/data/datasets/lvis.py","lineNumber":184,"sourceCode":"\n\ndef get_lvis_instances_meta(dataset_name):\n    \"\"\"\n    Load LVIS metadata.\n\n    Args:\n        dataset_name (str): LVIS dataset name without the split name (e.g., \"lvis_v0.5\").\n\n    Returns:\n        dict: LVIS metadata with keys: thing_classes\n    \"\"\"\n    if \"cocofied\" in dataset_name:\n        return _get_coco_instances_meta()\n    if \"v0.5\" in dataset_name:\n        return _get_lvis_instances_meta_v0_5()\n    elif \"v1\" in dataset_name:\n        return _get_lvis_instances_meta_v1()\n    raise ValueError(\"No built-in metadata for dataset {}\".format(dataset_name))\n\n\ndef _get_lvis_instances_meta_v0_5():\n    assert len(LVIS_V0_5_CATEGORIES) == 1230\n    cat_ids = [k[\"id\"] for k in LVIS_V0_5_CATEGORIES]\n    assert min(cat_ids) == 1 and max(cat_ids) == len(\n        cat_ids\n    ), \"Category ids are not in [1, #categories], as expected\"\n    # Ensure that the category list is sorted by id\n    lvis_categories = sorted(LVIS_V0_5_CATEGORIES, key=lambda x: x[\"id\"])\n    thing_classes = [k[\"synonyms\"][0] for k in lvis_categories]\n    meta = {\"thing_classes\": thing_classes}\n    return meta\n\n\ndef _get_lvis_instances_meta_v1():\n    assert len(LVIS_V1_CATEGORIES) == 1203\n    cat_ids = [k[\"id\"] for k in LVIS_V1_CATEGORIES]","sourceCodeStart":166,"sourceCodeEnd":202,"githubUrl":"https://github.com/facebookresearch/detectron2/blob/a2f4a8771ab77e8411c26b27f24f9489a28a2453/detectron2/data/datasets/lvis.py#L166-L202","documentation":"get_lvis_instances_meta resolves metadata by substring matching on the dataset name: names containing 'cocofied' get COCO metadata, 'v0.5' and 'v1' get LVIS versions. Any other LVIS-like name raises ValueError because no builtin metadata matches.","triggerScenarios":"Calling get_lvis_instances_meta('lvis_val') (no version substring) or a renamed LVIS dataset like 'lvis_v2_val'; also any call chain through register_all_lvis or load_lvis_json with an unrecognized name.","commonSituations":"Registering a custom LVIS variant with register_lvis_instances without setting MetadataCatalog yourself; dataset-name typos; newer LVIS versions unsupported by the installed detectron2.","solutions":["Include a recognized substring in the name ('v0.5' or 'v1'), or better, register metadata explicitly","For custom LVIS-format data call register_lvis_instances and set MetadataCatalog with your thing_classes/dataset_names","Upgrade detectron2 if you need a newer LVIS split"],"exampleFix":"# before\nmeta = get_lvis_instances_meta('lvis_val')\n# after\nMetadataCatalog.set('lvis_val', thing_classes=my_classes, dataset_name='lvis-val')\nmeta = MetadataCatalog.get('lvis_val')","handlingStrategy":"validation","validationCode":"from detectron2.data import MetadataCatalog\nif not MetadataCatalog.contains(dataset_name):\n    raise ValueError(f'register metadata for {dataset_name} before use')","typeGuard":"def lvis_meta_available(name: str) -> bool:\n    return any(s in name for s in ('cocofied', 'v0.5', 'v1'))","tryCatchPattern":"try:\n    meta = get_lvis_instances_meta(name)\nexcept ValueError:\n    MetadataCatalog.set(name, thing_classes=my_classes, dataset_name='lvis-val')\n    meta = MetadataCatalog.get(name)","preventionTips":["For custom LVIS data always use register_lvis_instances plus explicit MetadataCatalog.set","Name splits to include the version substring when reusing builtins","Pin detectron2 version matching your LVIS release"],"tags":["detectron2","lvis","metadata","dataset-registration"],"backgroundTag":"missing-dataset-metadata","analyzedSha":"a2f4a8771ab77e8411c26b27f24f9489a28a2453","analyzedAt":"2026-08-27T12:08:21.260Z","schemaVersion":2},"datasetVersion":"2026-08-27T13:17:12.746Z"}