close streams in prototype datasets (#6647)

* close streams in prototype datasets

* refactor prototype SBD to avoid closing demux streams at construction time

* mypy

test/builtin_dataset_mocks.py

@@ -661,15 +661,15 @@ class SBDMockData:
     _NUM_CATEGORIES = 20
 
     @classmethod
-    def _make_split_files(cls, root_map):
-        ids_map = {
-            split: [f"2008_{idx:06d}" for idx in idcs]
-            for split, idcs in (
-                ("train", [0, 1, 2]),
-                ("train_noval", [0, 2]),
-                ("val", [3]),
-            )
-        }
+    def _make_split_files(cls, root_map, *, split):
+        splits_and_idcs = [
+            ("train", [0, 1, 2]),
+            ("val", [3]),
+        ]
+        if split == "train_noval":
+            splits_and_idcs.append(("train_noval", [0, 2]))
+
+        ids_map = {split: [f"2008_{idx:06d}" for idx in idcs] for split, idcs in splits_and_idcs}
 
         for split, ids in ids_map.items():
             with open(root_map[split] / f"{split}.txt", "w") as fh:
@@ -710,12 +710,14 @@ class SBDMockData:
         return torch.randint(0, cls._NUM_CATEGORIES + 1, size=size, dtype=torch.uint8).numpy()
 
     @classmethod
-    def generate(cls, root):
+    def generate(cls, root, *, split):
         archive_folder = root / "benchmark_RELEASE"
         dataset_folder = archive_folder / "dataset"
         dataset_folder.mkdir(parents=True, exist_ok=True)
 
-        ids, num_samples_map = cls._make_split_files(defaultdict(lambda: dataset_folder, {"train_noval": root}))
+        ids, num_samples_map = cls._make_split_files(
+            defaultdict(lambda: dataset_folder, {"train_noval": root}), split=split
+        )
         sizes = cls._make_anns_folder(dataset_folder, "cls", ids)
         create_image_folder(
             dataset_folder, "img", lambda idx: f"{ids[idx]}.jpg", num_examples=len(ids), size=lambda idx: sizes[idx]
@@ -723,12 +725,12 @@ class SBDMockData:
 
         make_tar(root, "benchmark.tgz", archive_folder, compression="gz")
 
-        return num_samples_map
+        return num_samples_map[split]
 
 
 @register_mock(configs=combinations_grid(split=("train", "val", "train_noval")))
 def sbd(root, config):
-    return SBDMockData.generate(root)[config["split"]]
+    return SBDMockData.generate(root, split=config["split"])
 
 
 @register_mock(configs=[dict()])

test/test_prototype_datasets_builtin.py

 import functools
 import io
 import pickle
+from collections import deque
 from pathlib import Path
 
 import pytest
@@ -11,10 +12,11 @@ from torch.utils.data import DataLoader
 from torch.utils.data.graph import traverse_dps
 from torch.utils.data.graph_settings import get_all_graph_pipes
 from torchdata.datapipes.iter import ShardingFilter, Shuffler
+from torchdata.datapipes.utils import StreamWrapper
 from torchvision._utils import sequence_to_str
-from torchvision.prototype import datasets, transforms
+from torchvision.prototype import datasets, features, transforms
 from torchvision.prototype.datasets.utils._internal import INFINITE_BUFFER_SIZE
-from torchvision.prototype.features import Image, Label
+
 
 assert_samples_equal = functools.partial(
     assert_equal, pair_types=(TensorLikePair, ObjectPair), rtol=0, atol=0, equal_nan=True
@@ -25,6 +27,17 @@ def extract_datapipes(dp):
     return get_all_graph_pipes(traverse_dps(dp))
 
 
+def consume(iterator):
+    # Copied from the official itertools recipes: https://docs.python.org/3/library/itertools.html#itertools-recipes
+    deque(iterator, maxlen=0)
+
+
+def next_consume(iterator):
+    item = next(iterator)
+    consume(iterator)
+    return item
+
+
 @pytest.fixture(autouse=True)
 def test_home(mocker, tmp_path):
     mocker.patch("torchvision.prototype.datasets._api.home", return_value=str(tmp_path))
@@ -66,7 +79,7 @@ class TestCommon:
         dataset, _ = dataset_mock.load(config)
 
         try:
-            sample = next(iter(dataset))
+            sample = next_consume(iter(dataset))
         except StopIteration:
             raise AssertionError("Unable to draw any sample.") from None
         except Exception as error:
@@ -84,22 +97,53 @@ class TestCommon:
 
         assert len(list(dataset)) == mock_info["num_samples"]
 
+    @pytest.fixture
+    def log_session_streams(self):
+        debug_unclosed_streams = StreamWrapper.debug_unclosed_streams
+        try:
+            StreamWrapper.debug_unclosed_streams = True
+            yield
+        finally:
+            StreamWrapper.debug_unclosed_streams = debug_unclosed_streams
+
     @parametrize_dataset_mocks(DATASET_MOCKS)
-    def test_no_vanilla_tensors(self, dataset_mock, config):
+    def test_stream_closing(self, log_session_streams, dataset_mock, config):
+        def make_msg_and_close(head):
+            unclosed_streams = []
+            for stream in StreamWrapper.session_streams.keys():
+                unclosed_streams.append(repr(stream.file_obj))
+                stream.close()
+            unclosed_streams = "\n".join(unclosed_streams)
+            return f"{head}\n\n{unclosed_streams}"
+
+        if StreamWrapper.session_streams:
+            raise pytest.UsageError(make_msg_and_close("A previous test did not close the following streams:"))
+
         dataset, _ = dataset_mock.load(config)
 
-        vanilla_tensors = {key for key, value in next(iter(dataset)).items() if type(value) is torch.Tensor}
-        if vanilla_tensors:
+        consume(iter(dataset))
+
+        if StreamWrapper.session_streams:
+            raise AssertionError(make_msg_and_close("The following streams were not closed after a full iteration:"))
+
+    @parametrize_dataset_mocks(DATASET_MOCKS)
+    def test_no_simple_tensors(self, dataset_mock, config):
+        dataset, _ = dataset_mock.load(config)
+
+        simple_tensors = {key for key, value in next_consume(iter(dataset)).items() if features.is_simple_tensor(value)}
+        if simple_tensors:
             raise AssertionError(
                 f"The values of key(s) "
-                f"{sequence_to_str(sorted(vanilla_tensors), separate_last='and ')} contained vanilla tensors."
+                f"{sequence_to_str(sorted(simple_tensors), separate_last='and ')} contained simple tensors."
             )
 
     @parametrize_dataset_mocks(DATASET_MOCKS)
     def test_transformable(self, dataset_mock, config):
         dataset, _ = dataset_mock.load(config)
 
-        next(iter(dataset.map(transforms.Identity())))
+        dataset = dataset.map(transforms.Identity())
+
+        consume(iter(dataset))
 
     @parametrize_dataset_mocks(DATASET_MOCKS)
     def test_traversable(self, dataset_mock, config):
@@ -131,7 +175,7 @@ class TestCommon:
             collate_fn=self._collate_fn,
         )
 
-        next(iter(dl))
+        consume(dl)
 
     # TODO: we need to enforce not only that both a Shuffler and a ShardingFilter are part of the datapipe, but also
     #  that the Shuffler comes before the ShardingFilter. Early commits in https://github.com/pytorch/vision/pull/5680
@@ -148,7 +192,7 @@ class TestCommon:
     def test_save_load(self, dataset_mock, config):
         dataset, _ = dataset_mock.load(config)
 
-        sample = next(iter(dataset))
+        sample = next_consume(iter(dataset))
 
         with io.BytesIO() as buffer:
             torch.save(sample, buffer)
@@ -177,7 +221,7 @@ class TestQMNIST:
     def test_extra_label(self, dataset_mock, config):
         dataset, _ = dataset_mock.load(config)
 
-        sample = next(iter(dataset))
+        sample = next_consume(iter(dataset))
         for key, type in (
             ("nist_hsf_series", int),
             ("nist_writer_id", int),
@@ -214,7 +258,7 @@ class TestUSPS:
             assert "image" in sample
             assert "label" in sample
 
-            assert isinstance(sample["image"], Image)
-            assert isinstance(sample["label"], Label)
+            assert isinstance(sample["image"], features.Image)
+            assert isinstance(sample["label"], features.Label)
 
             assert sample["image"].shape == (1, 16, 16)

torchvision/prototype/datasets/_builtin/celeba.py

@@ -30,24 +30,26 @@ class CelebACSVParser(IterDataPipe[Tuple[str, Dict[str, str]]]):
 
     def __iter__(self) -> Iterator[Tuple[str, Dict[str, str]]]:
         for _, file in self.datapipe:
-            file = (line.decode() for line in file)
+            lines = (line.decode() for line in file)
 
             if self.fieldnames:
                 fieldnames = self.fieldnames
             else:
                 # The first row is skipped, because it only contains the number of samples
-                next(file)
+                next(lines)
 
                 # Empty field names are filtered out, because some files have an extra white space after the header
                 # line, which is recognized as extra column
-                fieldnames = [name for name in next(csv.reader([next(file)], dialect="celeba")) if name]
+                fieldnames = [name for name in next(csv.reader([next(lines)], dialect="celeba")) if name]
                 # Some files do not include a label for the image ID column
                 if fieldnames[0] != "image_id":
                     fieldnames.insert(0, "image_id")
 
-            for line in csv.DictReader(file, fieldnames=fieldnames, dialect="celeba"):
+            for line in csv.DictReader(lines, fieldnames=fieldnames, dialect="celeba"):
                 yield line.pop("image_id"), line
 
+            file.close()
+
 
 NAME = "celeba"
 

torchvision/prototype/datasets/_builtin/cifar.py

@@ -62,7 +62,9 @@ class _CifarBase(Dataset):
 
     def _unpickle(self, data: Tuple[str, io.BytesIO]) -> Dict[str, Any]:
         _, file = data
-        return cast(Dict[str, Any], pickle.load(file, encoding="latin1"))
+        content = cast(Dict[str, Any], pickle.load(file, encoding="latin1"))
+        file.close()
+        return content
 
     def _prepare_sample(self, data: Tuple[np.ndarray, int]) -> Dict[str, Any]:
         image_array, category_idx = data

torchvision/prototype/datasets/_builtin/clevr.py

@@ -97,6 +97,8 @@ class CLEVR(Dataset):
                 buffer_size=INFINITE_BUFFER_SIZE,
             )
         else:
+            for _, file in scenes_dp:
+                file.close()
             dp = Mapper(images_dp, self._add_empty_anns)
 
         return Mapper(dp, self._prepare_sample)

torchvision/prototype/datasets/_builtin/mnist.py

@@ -57,6 +57,8 @@ class MNISTFileReader(IterDataPipe[torch.Tensor]):
             for _ in range(stop - start):
                 yield read(dtype=dtype, count=count).reshape(shape)
 
+            file.close()
+
 
 class _MNISTBase(Dataset):
     _URL_BASE: Union[str, Sequence[str]]

torchvision/prototype/datasets/_builtin/pcam.py

@@ -33,6 +33,8 @@ class PCAMH5Reader(IterDataPipe[Tuple[str, io.IOBase]]):
                     data = data[self.key]
                 yield from data
 
+            handle.close()
+
 
 _Resource = namedtuple("_Resource", ("file_name", "gdrive_id", "sha256"))
 

torchvision/prototype/datasets/_builtin/sbd.py

@@ -49,31 +49,35 @@ class SBD(Dataset):
         super().__init__(root, dependencies=("scipy",), skip_integrity_check=skip_integrity_check)
 
     def _resources(self) -> List[OnlineResource]:
-        archive = HttpResource(
-            "https://www2.eecs.berkeley.edu/Research/Projects/CS/vision/grouping/semantic_contours/benchmark.tgz",
-            sha256="6a5a2918d5c73ce032fdeba876574d150d9d04113ab87540a1304cbcc715be53",
-        )
-        extra_split = HttpResource(
-            "http://home.bharathh.info/pubs/codes/SBD/train_noval.txt",
-            sha256="0b2068f7a359d2907431803e1cd63bf6162da37d7d503b589d3b08c6fd0c2432",
-        )
-        return [archive, extra_split]
+        resources = [
+            HttpResource(
+                "https://www2.eecs.berkeley.edu/Research/Projects/CS/vision/grouping/semantic_contours/benchmark.tgz",
+                sha256="6a5a2918d5c73ce032fdeba876574d150d9d04113ab87540a1304cbcc715be53",
+            )
+        ]
+        if self._split == "train_noval":
+            resources.append(
+                HttpResource(
+                    "http://home.bharathh.info/pubs/codes/SBD/train_noval.txt",
+                    sha256="0b2068f7a359d2907431803e1cd63bf6162da37d7d503b589d3b08c6fd0c2432",
+                )
+            )
+        return resources  # type: ignore[return-value]
 
     def _classify_archive(self, data: Tuple[str, Any]) -> Optional[int]:
         path = pathlib.Path(data[0])
         parent, grandparent, *_ = path.parents
 
-        if parent.name == "dataset":
-            return 0
-        elif grandparent.name == "dataset":
+        if grandparent.name == "dataset":
             if parent.name == "img":
-                return 1
+                return 0
             elif parent.name == "cls":
-                return 2
-            else:
-                return None
-        else:
-            return None
+                return 1
+
+        if parent.name == "dataset" and self._split != "train_noval":
+            return 2
+
+        return None
 
     def _prepare_sample(self, data: Tuple[Tuple[Any, Tuple[str, BinaryIO]], Tuple[str, BinaryIO]]) -> Dict[str, Any]:
         split_and_image_data, ann_data = data
@@ -93,18 +97,24 @@ class SBD(Dataset):
         )
 
     def _datapipe(self, resource_dps: List[IterDataPipe]) -> IterDataPipe[Dict[str, Any]]:
-        archive_dp, extra_split_dp = resource_dps
-
-        archive_dp = resource_dps[0]
-        split_dp, images_dp, anns_dp = Demultiplexer(
-            archive_dp,
-            3,
-            self._classify_archive,
-            buffer_size=INFINITE_BUFFER_SIZE,
-            drop_none=True,
-        )
         if self._split == "train_noval":
-            split_dp = extra_split_dp
+            archive_dp, split_dp = resource_dps
+            images_dp, anns_dp = Demultiplexer(
+                archive_dp,
+                2,
+                self._classify_archive,
+                buffer_size=INFINITE_BUFFER_SIZE,
+                drop_none=True,
+            )
+        else:
+            archive_dp = resource_dps[0]
+            images_dp, anns_dp, split_dp = Demultiplexer(
+                archive_dp,
+                3,
+                self._classify_archive,
+                buffer_size=INFINITE_BUFFER_SIZE,
+                drop_none=True,
+            )
 
         split_dp = Filter(split_dp, path_comparator("name", f"{self._split}.txt"))
         split_dp = LineReader(split_dp, decode=True)

torchvision/prototype/datasets/_builtin/voc.py

@@ -94,7 +94,9 @@ class VOC(Dataset):
             return None
 
     def _parse_detection_ann(self, buffer: BinaryIO) -> Dict[str, Any]:
-        return cast(Dict[str, Any], VOCDetection.parse_voc_xml(ElementTree.parse(buffer).getroot())["annotation"])
+        ann = cast(Dict[str, Any], VOCDetection.parse_voc_xml(ElementTree.parse(buffer).getroot())["annotation"])
+        buffer.close()
+        return ann
 
     def _prepare_detection_ann(self, buffer: BinaryIO) -> Dict[str, Any]:
         anns = self._parse_detection_ann(buffer)

torchvision/prototype/datasets/utils/_internal.py

@@ -8,7 +8,6 @@ import torch
 import torch.distributed as dist
 import torch.utils.data
 from torchdata.datapipes.iter import IoPathFileLister, IoPathFileOpener, IterDataPipe, ShardingFilter, Shuffler
-from torchdata.datapipes.utils import StreamWrapper
 from torchvision.prototype.utils._internal import fromfile
 
 
@@ -40,10 +39,9 @@ def read_mat(buffer: BinaryIO, **kwargs: Any) -> Any:
     except ImportError as error:
         raise ModuleNotFoundError("Package `scipy` is required to be installed to read .mat files.") from error
 
-    if isinstance(buffer, StreamWrapper):
-        buffer = buffer.file_obj
-
-    return sio.loadmat(buffer, **kwargs)
+    data = sio.loadmat(buffer, **kwargs)
+    buffer.close()
+    return data
 
 
 class MappingIterator(IterDataPipe[Union[Tuple[K, D], D]]):

torchvision/prototype/features/_encoded.py

@@ -27,7 +27,9 @@ class EncodedData(_Feature):
 
     @classmethod
     def from_file(cls: Type[D], file: BinaryIO, **kwargs: Any) -> D:
-        return cls(fromfile(file, dtype=torch.uint8, byte_order=sys.byteorder), **kwargs)
+        encoded_data = cls(fromfile(file, dtype=torch.uint8, byte_order=sys.byteorder), **kwargs)
+        file.close()
+        return encoded_data
 
     @classmethod
     def from_path(cls: Type[D], path: Union[str, os.PathLike], **kwargs: Any) -> D: