Docs and test

Author: Tinche

HISTORY.md

@@ -32,6 +32,9 @@ Our backwards-compatibility policy can be found [here](https://github.com/python
 - For {class}`cattrs.errors.StructureHandlerNotFoundError` and {class}`cattrs.errors.ForbiddenExtraKeysError`
   correctly set {attr}`BaseException.args` in `super()` and hence make them pickable.
   ([#666](https://github.com/python-attrs/cattrs/pull/666))
+- The default disambiguation hook factory is now only enabled for converters with `unstructure_strat=AS_DICT` (the default).
+  Since the strategy doesn't support tuples, it is skipped for `unstructure_strat=AS_TUPLE` converters.
+  ([#673](https://github.com/python-attrs/cattrs/pull/673))
 
 ## 25.1.1 (2025-06-04)
 

tests/test_disambiguators.py

@@ -113,6 +113,30 @@ class L:
         fn([])
 
 
+def test_input_not_mapping():
+    """Correct errors are raised when the raw payload isn't a mapping."""
+    c = Converter()
+
+    @define
+    class A:
+        a: int
+
+    @define
+    class B:
+        b: int
+
+    @define
+    class C:
+        pass
+
+    with pytest.raises(ValueError):
+        c.structure([], Union[A, B])
+
+    # Also test the fallback case
+    with pytest.raises(ValueError):
+        c.structure([], Union[A, B, C])
+
+
 @given(simple_classes(defaults=False))
 def test_fallback(cl_and_vals):
     """The fallback case works."""