BC: Switch map operator arguments order (#19345)

update

Co-authored-by: thomas <thomas@thomass-MacBook-Pro.local>

Author: tchaton

src/lightning/data/streaming/data_processor.py

@@ -563,7 +563,7 @@ def _handle_data_chunk_recipe_end(self) -> None:
     def _handle_data_transform_recipe(self, index: int) -> None:
         # Don't use a context manager to avoid deleting files that are being uploaded.
         output_dir = tempfile.mkdtemp()
-        item_data = self.data_recipe.prepare_item(str(output_dir), self.items[index])
+        item_data = self.data_recipe.prepare_item(self.items[index], str(output_dir))
         if item_data is not None:
             raise ValueError(
                 "When using a `DataTransformRecipe`, the `prepare_item` shouldn't return anything."
@@ -753,7 +753,7 @@ def prepare_structure(self, input_dir: Optional[str]) -> List[T]:
         """
 
     @abstractmethod
-    def prepare_item(self, output_dir: str, item_metadata: T) -> None:  # type: ignore
+    def prepare_item(self, item_metadata: T, output_dir: str) -> None:  # type: ignore
         """Use your item metadata to process your files and save the file outputs into `output_dir`."""
 
 

src/lightning/data/streaming/functions.py

@@ -82,24 +82,24 @@ def __init__(self, fn: Callable[[str, Any], None], inputs: Sequence[Any]):
         params = inspect.signature(_fn).parameters
         self._contains_device = "device" in params
 
-    def prepare_structure(self, input_dir: Optional[str]) -> Any:
+    def prepare_structure(self, _: Optional[str]) -> Any:
         return self._inputs
 
-    def prepare_item(self, output_dir: str, item_metadata: Any) -> None:  # type: ignore
+    def prepare_item(self, item_metadata: Any, output_dir: str) -> None:  # type: ignore
         if self._contains_device and self._device is None:
             self._find_device()
 
         if isinstance(self._fn, (FunctionType, partial)):
             if self._contains_device:
-                self._fn(output_dir, item_metadata, self._device)
+                self._fn(item_metadata, output_dir, self._device)
             else:
-                self._fn(output_dir, item_metadata)
+                self._fn(item_metadata, output_dir)
 
         elif callable(self._fn):
             if self._contains_device:
-                self._fn.__call__(output_dir, item_metadata, self._device)  # type: ignore
+                self._fn.__call__(item_metadata, output_dir, self._device)  # type: ignore
             else:
-                self._fn.__call__(output_dir, item_metadata)  # type: ignore
+                self._fn.__call__(item_metadata, output_dir)  # type: ignore
         else:
             raise ValueError(f"The provided {self._fn} isn't supported.")
 

tests/tests_data/streaming/test_data_processor.py

@@ -581,7 +581,7 @@ def prepare_structure(self, input_dir: str):
         filepaths = [os.path.join(input_dir, filename) for filename in os.listdir(input_dir)]
         return [filepath for filepath in filepaths if os.path.isfile(filepath)]
 
-    def prepare_item(self, output_dir: str, filepath: Any) -> None:
+    def prepare_item(self, filepath: Any, output_dir: str) -> None:
         from PIL import Image
 
         img = Image.open(filepath)
@@ -628,7 +628,7 @@ def test_data_process_transform(monkeypatch, tmpdir):
     assert img.size == (12, 12)
 
 
-def map_fn(output_dir, filepath):
+def map_fn(filepath, output_dir):
     from PIL import Image
 
     img = Image.open(filepath)
@@ -833,7 +833,7 @@ def fn(output_dir, item, device):
 
     data_recipe = LambdaDataTransformRecipe(fn, range(1))
 
-    data_recipe.prepare_item("", 1)
+    data_recipe.prepare_item(1, "")
     assert called
 
 
@@ -847,13 +847,13 @@ def test_lambda_transform_recipe_class(monkeypatch):
     called = False
 
     class Transform:
-        def __call__(self, output_dir, item, device):
+        def __call__(self, item, output_dir, device):
             nonlocal called
             assert device == "cuda:2"
             called = True
 
     data_recipe = LambdaDataTransformRecipe(Transform(), range(1))
-    data_recipe.prepare_item("", 1)
+    data_recipe.prepare_item(1, "")
     assert called
 
 
@@ -894,7 +894,7 @@ def test_get_item_filesizes(tmp_path):
         _get_item_filesizes([str(tmp_path / "empty_file")])
 
 
-def map_fn_index(output_dir, index):
+def map_fn_index(index, output_dir):
     with open(os.path.join(output_dir, f"{index}.JPEG"), "w") as f:
         f.write("Hello")