Allowed setting attributes on DataLoader and BatchSampler when in…

…stantiated inside `*_dataloader` hooks (#14212)

src/pytorch_lightning/CHANGELOG.md

@@ -101,6 +101,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Avoided requiring the FairScale package to use precision with the fsdp native strategy ([#14092](https://github.com/Lightning-AI/lightning/pull/14092))
 
 
+- Fixed not preserving set attributes on `DataLoader` and `BatchSampler` when instantiated inside `*_dataloader` hooks ([#14212](https://github.com/Lightning-AI/lightning/pull/14212))
+
+
 ## [1.7.1] - 2022-08-09
 
 ### Fixed

src/pytorch_lightning/lite/lite.py

@@ -35,7 +35,7 @@
 from pytorch_lightning.utilities.apply_func import apply_to_collection, convert_to_tensors
 from pytorch_lightning.utilities.data import (
     _auto_add_worker_init_fn,
-    _replace_init_method,
+    _replace_dunder_methods,
     _update_dataloader,
     has_iterable_dataset,
 )
@@ -403,9 +403,9 @@ def _run_impl(self, run_method: Callable, *args: Any, **kwargs: Any) -> Any:
 
     def _run_with_strategy_setup(self, run_method: Callable, *args: Any, **kwargs: Any) -> Any:
         self._strategy.setup_environment()
-        with self._strategy.model_sharded_context(), _replace_init_method(DataLoader, "dataset"), _replace_init_method(
-            BatchSampler
-        ):
+        with self._strategy.model_sharded_context(), _replace_dunder_methods(
+            DataLoader, "dataset"
+        ), _replace_dunder_methods(BatchSampler):
             return run_method(*args, **kwargs)
 
     def _move_model_to_device(self, model: nn.Module, optimizers: List[Optimizer]) -> nn.Module:

src/pytorch_lightning/strategies/ipu.py

@@ -31,7 +31,7 @@
 from pytorch_lightning.utilities import _IPU_AVAILABLE, _POPTORCH_AVAILABLE, rank_zero_warn
 from pytorch_lightning.utilities.apply_func import apply_to_collection
 from pytorch_lightning.utilities.cloud_io import get_filesystem
-from pytorch_lightning.utilities.data import _get_dataloader_init_args_and_kwargs
+from pytorch_lightning.utilities.data import _get_dataloader_init_args_and_kwargs, _reinstantiate_wrapped_cls
 from pytorch_lightning.utilities.enums import PrecisionType
 from pytorch_lightning.utilities.exceptions import MisconfigurationException
 from pytorch_lightning.utilities.model_helpers import is_overridden
@@ -248,7 +248,9 @@ def _convert_to_poptorch_loader(
             dataloader, sampler, mode, self.replication_factor > 1  # type: ignore[arg-type]
         )
         opts = self.training_opts if mode == RunningStage.TRAINING else self.inference_opts
-        dataloader = poptorch.DataLoader(opts, *dl_args, **dl_kwargs)
+        dataloader = _reinstantiate_wrapped_cls(
+            dataloader, opts, *dl_args, explicit_cls=poptorch.DataLoader, **dl_kwargs
+        )
         return dataloader
 
     def _handle_gradient_accumulation_steps(self) -> None:

src/pytorch_lightning/trainer/connectors/data_connector.py

@@ -31,7 +31,7 @@
 from pytorch_lightning.utilities.data import (
     _auto_add_worker_init_fn,
     _is_dataloader_shuffled,
-    _replace_init_method,
+    _replace_dunder_methods,
     _update_dataloader,
     has_iterable_dataset,
     has_len_all_ranks,
@@ -428,9 +428,11 @@ def _request_dataloader(self, stage: RunningStage) -> Union[DataLoader, List[Dat
         """
         source = getattr(self, f"_{stage.dataloader_prefix}_dataloader_source")
 
-        with _replace_init_method(DataLoader, "dataset"), _replace_init_method(BatchSampler):
+        with _replace_dunder_methods(DataLoader, "dataset"), _replace_dunder_methods(BatchSampler):
             # under this context manager, the arguments passed to `DataLoader.__init__` will be captured and saved as
-            # attributes on the instance in case the dataloader needs to be re-instantiated later by Lightning
+            # attributes on the instance in case the dataloader needs to be re-instantiated later by Lightning.
+            # Also, it records all attribute setting and deletion using patched `__setattr__` and `__delattr__`
+            # methods so that the re-instantiated object is as close to the original as possible.
             dataloader = source.dataloader()
         if isinstance(dataloader, tuple):
             dataloader = list(dataloader)

src/pytorch_lightning/utilities/data.py

@@ -37,7 +37,7 @@
 from pytorch_lightning.trainer.states import RunningStage
 from pytorch_lightning.utilities.apply_func import _is_dataclass_instance
 from pytorch_lightning.utilities.auto_restart import CaptureIterableDataset, CaptureMapDataset, FastForwardSampler
-from pytorch_lightning.utilities.enums import _FaultTolerantMode
+from pytorch_lightning.utilities.enums import _FaultTolerantMode, LightningEnum
 from pytorch_lightning.utilities.exceptions import MisconfigurationException
 from pytorch_lightning.utilities.meta import _get_all_subclasses
 from pytorch_lightning.utilities.rank_zero import rank_zero_warn
@@ -49,6 +49,18 @@
 warning_cache = WarningCache()
 
 
+class _WrapAttrTag(LightningEnum):
+    SET = "set"
+    DEL = "del"
+
+    def __call__(self, *args):
+        if self == self.SET:
+            fn = setattr
+        else:
+            fn = delattr
+        return fn(*args)
+
+
 def _extract_batch_size(batch: BType) -> Generator[int, None, None]:
     if isinstance(batch, Tensor):
         if batch.ndim == 0:
@@ -189,27 +201,7 @@ def _update_dataloader(
     dataloader: DataLoader, sampler: Union[Sampler, Iterable], mode: Optional[RunningStage] = None
 ) -> DataLoader:
     dl_args, dl_kwargs = _get_dataloader_init_args_and_kwargs(dataloader, sampler, mode)
-    dl_cls = type(dataloader)
-    try:
-        dataloader = dl_cls(*dl_args, **dl_kwargs)
-    except TypeError as e:
-        # improve exception message due to an incorrect implementation of the `DataLoader` where multiple subclass
-        # `__init__` arguments map to one `DataLoader.__init__` argument
-        import re
-
-        match = re.match(r".*__init__\(\) got multiple values .* '(\w+)'", str(e))
-        if not match:
-            # an unexpected `TypeError`, continue failure
-            raise
-        argument = match.groups()[0]
-        message = (
-            f"The {dl_cls.__name__} `DataLoader` implementation has an error where more than one `__init__` argument"
-            f" can be passed to its parent's `{argument}=...` `__init__` argument. This is likely caused by allowing"
-            f" passing both a custom argument that will map to the `{argument}` argument as well as `**kwargs`."
-            f" `kwargs` should be filtered to make sure they don't contain the `{argument}` key."
-            " This argument was automatically passed to your DataLoader by PyTorch Lightning."
-        )
-        raise MisconfigurationException(message) from e
+    dataloader = _reinstantiate_wrapped_cls(dataloader, *dl_args, **dl_kwargs)
     return dataloader
 
 
@@ -375,7 +367,7 @@ def _dataloader_init_kwargs_resolve_sampler(
                         "this, expose an argument `sampler` in the `__init__` method of your custom class."
                     )
 
-                batch_sampler = batch_sampler_cls(*args, **kwargs)
+                batch_sampler = _reinstantiate_wrapped_cls(batch_sampler, *args, **kwargs)
             else:
                 try:
                     batch_sampler = batch_sampler_cls(
@@ -450,6 +442,37 @@ def _auto_add_worker_init_fn(dataloader: DataLoader, rank: int) -> None:
         dataloader.worker_init_fn = partial(pl_worker_init_function, rank=rank)
 
 
+def _reinstantiate_wrapped_cls(orig_object: Any, *args: Any, explicit_cls: Optional[Type] = None, **kwargs: Any) -> Any:
+    constructor = type(orig_object) if explicit_cls is None else explicit_cls
+
+    try:
+        result = constructor(*args, **kwargs)
+    except TypeError as e:
+        # improve exception message due to an incorrect implementation of the `DataLoader` where multiple subclass
+        # `__init__` arguments map to one `DataLoader.__init__` argument
+        import re
+
+        match = re.match(r".*__init__\(\) got multiple values .* '(\w+)'", str(e))
+        if not match:
+            # an unexpected `TypeError`, continue failure
+            raise
+        argument = match.groups()[0]
+        message = (
+            f"The {constructor.__name__} implementation has an error where more than one `__init__` argument"
+            f" can be passed to its parent's `{argument}=...` `__init__` argument. This is likely caused by allowing"
+            f" passing both a custom argument that will map to the `{argument}` argument as well as `**kwargs`."
+            f" `kwargs` should be filtered to make sure they don't contain the `{argument}` key."
+            " This argument was automatically passed to your object by PyTorch Lightning."
+        )
+        raise MisconfigurationException(message) from e
+
+    attrs_record = getattr(orig_object, "__pl_attrs_record", list())
+    for args, fn in attrs_record:
+        fn(result, *args)
+
+    return result
+
+
 def _wrap_init_method(init: Callable, store_explicit_arg: Optional[str] = None) -> Callable:
     """Wraps the ``__init__`` method of classes (currently :class:`~torch.utils.data.DataLoader` and
     :class:`~torch.utils.data.BatchSampler`) in order to enable re-instantiation of custom subclasses."""
@@ -458,6 +481,8 @@ def _wrap_init_method(init: Callable, store_explicit_arg: Optional[str] = None)
     def wrapper(obj: Any, *args: Any, **kwargs: Any) -> None:
         # We need to inspect `init`, as inspecting `obj.__init__`
         # can lead to inspecting the wrong function with multiple inheritance
+        old_inside_init = getattr(obj, "__pl_inside_init", False)
+        object.__setattr__(obj, "__pl_inside_init", True)
         params = inspect.signature(init).parameters
 
         parameters_defaults = OrderedDict(
@@ -475,45 +500,82 @@ def wrapper(obj: Any, *args: Any, **kwargs: Any) -> None:
         }
 
         if not hasattr(obj, "__pl_saved_args"):
-            obj.__pl_saved_args = args
-            obj.__pl_saved_kwargs = kwargs
-            obj.__pl_saved_arg_names = param_names
-            obj.__pl_saved_default_kwargs = default_kwargs
+            object.__setattr__(obj, "__pl_saved_args", args)
+            object.__setattr__(obj, "__pl_saved_kwargs", kwargs)
+            object.__setattr__(obj, "__pl_saved_arg_names", param_names)
+            object.__setattr__(obj, "__pl_saved_default_kwargs", default_kwargs)
 
         # We want to use the latest possible value for explicit argument (i.e. ideally what gets passed to base class)
         # so that we can be sure, that it will not get changed anymore.
         # That is why we are setting this in every `__init__`
         if store_explicit_arg is not None:
             if store_explicit_arg in param_names:
-                setattr(obj, f"__{store_explicit_arg}", args[param_names.index(store_explicit_arg)])
+                object.__setattr__(obj, f"__{store_explicit_arg}", args[param_names.index(store_explicit_arg)])
             elif store_explicit_arg in kwargs:
-                setattr(obj, f"__{store_explicit_arg}", kwargs[store_explicit_arg])
+                object.__setattr__(obj, f"__{store_explicit_arg}", kwargs[store_explicit_arg])
 
         init(obj, *args, **kwargs)
+        object.__setattr__(obj, "__pl_inside_init", old_inside_init)
+
+    return wrapper
+
+
+def _wrap_attr_method(method: Callable, tag: _WrapAttrTag) -> Callable:
+    """Wraps the ``__setattr__`` or ``__delattr__`` method of classes (currently :class:`~torch.utils.data.DataLoader` and
+    :class:`~torch.utils.data.BatchSampler`) in order to enable re-instantiation of custom subclasses."""
+
+    @functools.wraps(method)
+    def wrapper(obj: Any, *args: Any):
+        # First, let's find out if we're the first in inheritance chain calling the patched method.
+        name, *_ = args
+        prev_call_name, prev_call_method = getattr(obj, "__pl_current_call", (None, "method"))
+        first_call = not (prev_call_name == name and prev_call_method == tag)
+
+        # Then mark the current called method
+        object.__setattr__(obj, "__pl_current_call", (name, tag))
+
+        # call original method
+        method(obj, *args)
+        if first_call and not getattr(obj, "__pl_inside_init", True):
+            # and save the value it was called with to the internal list,
+            # if we're outside of __init__ and the original call did not fail and we're the first call
+            attrs_record = getattr(obj, "__pl_attrs_record", list())
+            attrs_record.append((args, tag))
+            object.__setattr__(obj, "__pl_attrs_record", attrs_record)
+        object.__setattr__(obj, "__pl_current_call", (prev_call_name, prev_call_method))
 
     return wrapper
 
 
 @contextmanager
-def _replace_init_method(base_cls: Type, store_explicit_arg: Optional[str] = None) -> Generator[None, None, None]:
+def _replace_dunder_methods(base_cls: Type, store_explicit_arg: Optional[str] = None) -> Generator[None, None, None]:
     """This context manager is used to add support for re-instantiation of custom (subclasses) of `base_cls`.
 
-    It patches the ``__init__`` method.
+    It patches the ``__init__``, ``__setattr__`` and ``__delattr__`` methods.
     """
     classes = _get_all_subclasses(base_cls) | {base_cls}
     for cls in classes:
         # Check that __init__ belongs to the class
         # https://stackoverflow.com/a/5253424
         if "__init__" in cls.__dict__:
-            cls._old_init = cls.__init__
+            cls.__old__init__ = cls.__init__
             cls.__init__ = _wrap_init_method(cls.__init__, store_explicit_arg)
+
+        # we want at least one setattr/delattr in the chain to be patched and it can happen, that none of the subclasses
+        # implement `__setattr__`/`__delattr__`. Therefore, we are always patching the `base_cls`
+        for patch_fn_name, tag in (("__setattr__", _WrapAttrTag.SET), ("__delattr__", _WrapAttrTag.DEL)):
+            if patch_fn_name in cls.__dict__ or cls is base_cls:
+                saved_name = f"__old{patch_fn_name}"
+                setattr(cls, saved_name, getattr(cls, patch_fn_name))
+                setattr(cls, patch_fn_name, _wrap_attr_method(getattr(cls, patch_fn_name), tag))
     yield
     for cls in classes:
-        # Check that _old_init belongs to the class
-        # https://stackoverflow.com/a/5253424
-        if "_old_init" in cls.__dict__:
-            cls.__init__ = cls._old_init
-            del cls._old_init
+        for patched_name in ("__setattr__", "__delattr__", "__init__"):
+            # Check that __old__{init,setattr,delattr} belongs to the class
+            # https://stackoverflow.com/a/5253424
+            if f"__old{patched_name}" in cls.__dict__:
+                setattr(cls, patched_name, getattr(cls, f"__old{patched_name}"))
+                delattr(cls, f"__old{patched_name}")
 
 
 def _wrap_with_capture_dataset(dataset: Dataset) -> Dataset:

tests/tests_pytorch/lite/test_lite.py

@@ -177,7 +177,7 @@ def test_setup_dataloaders_return_type():
     assert lite_dataloader1.dataset is dataset1
 
 
-@mock.patch("pytorch_lightning.lite.lite._replace_init_method")
+@mock.patch("pytorch_lightning.lite.lite._replace_dunder_methods")
 def test_setup_dataloaders_captures_dataloader_arguments(ctx_manager):
     """Test that Lite intercepts the DataLoader constructor arguments with a context manager in its run method."""