Raise validation error when no transforms passed to RandomApply, RandomChoice and RandomOrder. (#9130)

Co-authored-by: Nicolas Hug <[email protected]>

Author: GdoongMathew

test/test_transforms_v2.py

@@ -2520,14 +2520,29 @@ def test_errors(self):
             with pytest.raises(TypeError, match="Argument transforms should be a sequence of callables"):
                 cls(lambda x: x)
 
-        with pytest.raises(ValueError, match="at least one transform"):
-            transforms.Compose([])
+        for cls in (
+            transforms.Compose,
+            transforms.RandomApply,
+            transforms.RandomChoice,
+            transforms.RandomOrder,
+        ):
+
+            with pytest.raises(ValueError, match="at least one transform"):
+                cls([])
 
         for p in [-1, 2]:
             with pytest.raises(ValueError, match=re.escape("value in the interval [0.0, 1.0]")):
                 transforms.RandomApply([lambda x: x], p=p)
 
-        for transforms_, p in [([lambda x: x], []), ([], [1.0])]:
+        for transforms_, p in [
+            ([lambda x: x], []),
+            (
+                [lambda x: x, lambda x: x],
+                [
+                    1.0,
+                ],
+            ),
+        ]:
             with pytest.raises(ValueError, match="Length of p doesn't match the number of transforms"):
                 transforms.RandomChoice(transforms_, p=p)
 

torchvision/transforms/v2/_container.py

@@ -87,6 +87,8 @@ def __init__(self, transforms: Union[Sequence[Callable], nn.ModuleList], p: floa
 
         if not isinstance(transforms, (Sequence, nn.ModuleList)):
             raise TypeError("Argument transforms should be a sequence of callables or a `nn.ModuleList`")
+        elif not transforms:
+            raise ValueError("Pass at least one transform")
         self.transforms = transforms
 
         if not (0.0 <= p <= 1.0):
@@ -133,7 +135,8 @@ def __init__(
     ) -> None:
         if not isinstance(transforms, Sequence):
             raise TypeError("Argument transforms should be a sequence of callables")
-
+        elif not transforms:
+            raise ValueError("Pass at least one transform")
         if p is None:
             p = [1] * len(transforms)
         elif len(p) != len(transforms):
@@ -163,6 +166,8 @@ class RandomOrder(Transform):
     def __init__(self, transforms: Sequence[Callable]) -> None:
         if not isinstance(transforms, Sequence):
             raise TypeError("Argument transforms should be a sequence of callables")
+        elif not transforms:
+            raise ValueError("Pass at least one transform")
         super().__init__()
         self.transforms = transforms