Fix check_output_custom uses applies_to

hamilton/function_modifiers/validation.py

@@ -186,7 +186,11 @@ def __init__(self, *validators: dq_base.DataValidator, target_: base.TargetType
         self.validators = list(validators)
 
     def get_validators(self, node_to_validate: node.Node) -> list[dq_base.DataValidator]:
-        return self.validators
+        return [
+            validator
+            for validator in self.validators
+            if validator.applies_to(node_to_validate.type)
+        ]
 
 
 class check_output(BaseDataValidationDecorator):

tests/function_modifiers/test_validation.py

@@ -128,6 +128,31 @@ def fn(input: pd.Series) -> pd.Series:
     )
 
 
+def test_check_output_custom_only_uses_applicable_validators():
+    applicable_validator = SampleDataValidator1(equal_to=10, importance="warn")
+    incompatible_validator = SampleDataValidator2(dataset_length=1, importance="warn")
+    decorator = check_output_custom(applicable_validator, incompatible_validator)
+
+    def fn(input: int) -> int:
+        return input
+
+    validators = decorator.get_validators(node.Node.from_fn(fn))
+
+    assert validators == [applicable_validator]
+
+
+def test_check_output_custom_uses_no_incompatible_validators():
+    decorator = check_output_custom(
+        SampleDataValidator2(dataset_length=1, importance="warn"),
+        SampleDataValidator3(dtype=np.int64, importance="warn"),
+    )
+
+    def fn(input: int) -> int:
+        return input
+
+    assert decorator.get_validators(node.Node.from_fn(fn)) == []
+
+
 def test_check_output_custom_node_transform_duplicate():
     """You should be able to pass in the same validator twice; IRL it would be different args."""
     decorator = check_output_custom(