Add test

Author: Tinche

src/cattrs/strategies/_listfromdict.py

@@ -9,6 +9,12 @@
 
 from .. import BaseConverter, SimpleStructureHook
 from ..dispatch import UnstructureHook
+from ..errors import (
+    AttributeValidationNote,
+    ClassValidationError,
+    IterableValidationError,
+    IterableValidationNote,
+)
 from ..fns import identity
 from ..gen.typeddicts import is_typeddict
 
@@ -48,14 +54,84 @@ def configure_list_from_dict(
     if isinstance(field, Attribute):
         field = field.name
 
-    def structure_hook(
-        value: Mapping,
-        _: Any = seq_type,
-        _arg_type=arg_type,
-        _arg_hook=arg_structure_hook,
-        _field=field,
-    ) -> list[T]:
-        return [_arg_hook(v | {_field: k}, _arg_type) for k, v in value.items()]
+    if converter.detailed_validation:
+
+        def structure_hook(
+            value: Mapping,
+            _: Any = seq_type,
+            _arg_type=arg_type,
+            _arg_hook=arg_structure_hook,
+            _field=field,
+        ) -> list[T]:
+            res = []
+            errors = []
+            for k, v in value.items():
+                try:
+                    res.append(_arg_hook(v | {_field: k}, _arg_type))
+                except ClassValidationError as exc:
+                    # Rewrite the notes of any errors relating to `_field`
+                    non_key_exceptions = []
+                    key_exceptions = []
+                    for inner_exc in exc.exceptions:
+                        if not (existing := getattr(inner_exc, "__notes__", [])):
+                            non_key_exceptions.append(inner_exc)
+                            continue
+                        for note in existing:
+                            if not isinstance(note, AttributeValidationNote):
+                                continue
+                            if note.name == _field:
+                                inner_exc.__notes__.remove(note)
+                                inner_exc.__notes__.append(
+                                    IterableValidationNote(
+                                        f"Structuring mapping key @ key {k!r}",
+                                        note.name,
+                                        note.type,
+                                    )
+                                )
+                                key_exceptions.append(inner_exc)
+                                break
+                        else:
+                            non_key_exceptions.append(inner_exc)
+
+                    if non_key_exceptions != exc.exceptions:
+                        if non_key_exceptions:
+                            errors.append(
+                                new_exc := ClassValidationError(
+                                    exc.message, non_key_exceptions, exc.cl
+                                )
+                            )
+                            new_exc.__notes__ = [
+                                *getattr(exc, "__notes__", []),
+                                IterableValidationNote(
+                                    "Structuring mapping value @ key {k!r}",
+                                    k,
+                                    _arg_type,
+                                ),
+                            ]
+                    else:
+                        exc.__notes__ = [
+                            *getattr(exc, "__notes__", []),
+                            IterableValidationNote(
+                                "Structuring mapping value @ key {k!r}", k, _arg_type
+                            ),
+                        ]
+                        errors.append(exc)
+                    if key_exceptions:
+                        errors.extend(key_exceptions)
+            if errors:
+                raise IterableValidationError("While structuring", errors, dict)
+            return res
+
+    else:
+
+        def structure_hook(
+            value: Mapping,
+            _: Any = seq_type,
+            _arg_type=arg_type,
+            _arg_hook=arg_structure_hook,
+            _field=field,
+        ) -> list[T]:
+            return [_arg_hook(v | {_field: k}, _arg_type) for k, v in value.items()]
 
     arg_unstructure_hook = converter.get_unstructure_hook(arg_type, cache_result=False)
 

tests/strategies/test_list_from_dict.py

@@ -6,25 +6,28 @@
 import pytest
 from attrs import define, fields
 
-from cattrs import BaseConverter
+from cattrs import BaseConverter, transform_error
+from cattrs.converters import Converter
+from cattrs.errors import IterableValidationError
+from cattrs.gen import make_dict_structure_fn, override
 from cattrs.strategies import configure_list_from_dict
 
 
 @define
 class AttrsA:
     a: int
-    b: str
+    b: int
 
 
 @dataclass
 class DataclassA:
     a: int
-    b: str
+    b: int
 
 
 class TypedDictA(TypedDict):
     a: int
-    b: str
+    b: int
 
 
 @pytest.mark.parametrize("cls", [AttrsA, DataclassA, TypedDictA])
@@ -33,18 +36,54 @@ def test_simple_roundtrip(
 ):
     hook, hook2 = configure_list_from_dict(list[cls], "a", converter)
 
-    structured = [cls(a=1, b="2"), cls(a=3, b="4")]
+    structured = [cls(a=1, b=2), cls(a=3, b=4)]
     unstructured = hook2(structured)
-    assert unstructured == {1: {"b": "2"}, 3: {"b": "4"}}
+    assert unstructured == {1: {"b": 2}, 3: {"b": 4}}
 
     assert hook(unstructured) == structured
 
 
 def test_simple_roundtrip_attrs(converter: BaseConverter):
     hook, hook2 = configure_list_from_dict(list[AttrsA], fields(AttrsA).a, converter)
 
-    structured = [AttrsA(a=1, b="2"), AttrsA(a=3, b="4")]
+    structured = [AttrsA(a=1, b=2), AttrsA(a=3, b=4)]
     unstructured = hook2(structured)
-    assert unstructured == {1: {"b": "2"}, 3: {"b": "4"}}
+    assert unstructured == {1: {"b": 2}, 3: {"b": 4}}
 
     assert hook(unstructured) == structured
+
+
+def test_validation_errors():
+    """
+    With detailed validation, validation errors should be adjusted for the
+    extracted keys.
+    """
+    conv = Converter(detailed_validation=True)
+    hook, _ = configure_list_from_dict(list[AttrsA], "a", conv)
+
+    # Key failure
+    with pytest.raises(IterableValidationError) as exc:
+        hook({"a": {"b": "1"}})
+
+    assert transform_error(exc.value) == [
+        "invalid value for type, expected int @ $['a']"
+    ]
+
+    # Value failure
+    with pytest.raises(IterableValidationError) as exc:
+        hook({1: {"b": "a"}})
+
+    assert transform_error(exc.value) == [
+        "invalid value for type, expected int @ $[1].b"
+    ]
+
+    conv.register_structure_hook(
+        AttrsA, make_dict_structure_fn(AttrsA, conv, _cattrs_forbid_extra_keys=True)
+    )
+    hook, _ = configure_list_from_dict(list[AttrsA], "a", conv)
+
+    # Value failure, not attribute related
+    with pytest.raises(IterableValidationError) as exc:
+        hook({1: {"b": 1, "c": 2}})
+
+    assert transform_error(exc.value) == ["extra fields found (c) @ $[1]"]