Add ForbiddenExtraKeysError to ClassValidationError if used.

Author: raabf

src/cattrs/gen.py

@@ -262,6 +262,10 @@ def make_dict_structure_fn(
         resolve_types(cl)
 
     allowed_fields = set()
+    if _cattrs_forbid_extra_keys:
+        globs["__c_a"] = allowed_fields
+        globs["__c_feke"] = ForbiddenExtraKeysError
+
     if _cattrs_detailed_validation:
         lines.append("  res = {}")
         lines.append("  errors = []")
@@ -327,6 +331,14 @@ def make_dict_structure_fn(
                 f"{i}e.__note__ = 'Structuring class {cl.__qualname__} @ attribute {an}'"
             )
             lines.append(f"{i}errors.append(e)")
+
+        if _cattrs_forbid_extra_keys:
+            post_lines += [
+                "  unknown_fields = set(o.keys()) - __c_a",
+                "  if unknown_fields:",
+                "    errors.append(__c_feke('', __cl, unknown_fields))",
+            ]
+
         post_lines.append(
             f"  if errors: raise __c_cve('While structuring {cl.__name__}', errors, __cl)"
         )
@@ -449,14 +461,12 @@ def make_dict_structure_fn(
             ["  return __cl("] + [f"    {line}" for line in invocation_lines] + ["  )"]
         )
 
-    if _cattrs_forbid_extra_keys:
-        globs["__c_a"] = allowed_fields
-        globs["__c_feke"] = ForbiddenExtraKeysError
-        lines += [
-            "  unknown_fields = set(o.keys()) - __c_a",
-            "  if unknown_fields:",
-            "    raise __c_feke('', __cl, unknown_fields)",
-        ]
+        if _cattrs_forbid_extra_keys:
+            post_lines += [
+                "  unknown_fields = set(o.keys()) - __c_a",
+                "  if unknown_fields:",
+                "    raise __c_feke('', __cl, unknown_fields)",
+            ]
 
     # At the end, we create the function header.
     internal_arg_line = ", ".join([f"{i}={i}" for i in internal_arg_parts])

tests/metadata/test_genconverter.py

@@ -20,7 +20,7 @@
 from cattr import UnstructureStrategy
 from cattr._compat import is_py39_plus, is_py310_plus
 from cattr.gen import make_dict_structure_fn, override
-from cattrs.errors import ForbiddenExtraKeysError
+from cattrs.errors import ClassValidationError, ForbiddenExtraKeysError
 
 from . import (
     nested_typed_classes,
@@ -88,11 +88,13 @@ def test_forbid_extra_keys(cls_and_vals):
     while bad_key in unstructured:
         bad_key += "A"
     unstructured[bad_key] = 1
-    with pytest.raises(ForbiddenExtraKeysError) as feke:
+    with pytest.raises(ClassValidationError) as cve:
         converter.structure(unstructured, cl)
 
-    assert feke.value.cl is cl
-    assert feke.value.extra_fields == {bad_key}
+    assert len(cve.value.exceptions) == 1
+    assert isinstance(cve.value.exceptions[0], ForbiddenExtraKeysError)
+    assert cve.value.exceptions[0].cl is cl
+    assert cve.value.exceptions[0].extra_fields == {bad_key}
 
 
 @given(simple_typed_attrs(defaults=True))
@@ -106,11 +108,13 @@ def test_forbid_extra_keys_defaults(attr_and_vals):
     inst = cl()
     unstructured = converter.unstructure(inst)
     unstructured["aa"] = unstructured.pop("a")
-    with pytest.raises(ForbiddenExtraKeysError) as feke:
+    with pytest.raises(ClassValidationError) as cve:
         converter.structure(unstructured, cl)
 
-    assert feke.value.cl is cl
-    assert feke.value.extra_fields == {"aa"}
+    assert len(cve.value.exceptions) == 1
+    assert isinstance(cve.value.exceptions[0], ForbiddenExtraKeysError)
+    assert cve.value.exceptions[0].cl is cl
+    assert cve.value.exceptions[0].extra_fields == {"aa"}
 
 
 def test_forbid_extra_keys_nested_override():
@@ -129,17 +133,30 @@ class A:
     converter.structure(unstructured, A)
     # if we break it in the subclass, we need it to raise
     unstructured["c"]["aa"] = 5
-    with pytest.raises(ForbiddenExtraKeysError):
+    with pytest.raises(ClassValidationError) as cve:
         converter.structure(unstructured, A)
+
+    assert len(cve.value.exceptions) == 1
+    assert isinstance(cve.value.exceptions[0], ClassValidationError)
+    assert len(cve.value.exceptions[0].exceptions) == 1
+    assert isinstance(cve.value.exceptions[0].exceptions[0], ForbiddenExtraKeysError)
+    assert cve.value.exceptions[0].exceptions[0].cl is C
+    assert cve.value.exceptions[0].exceptions[0].extra_fields == {"aa"}
+
     # we can "fix" that by disabling forbid_extra_keys on the subclass
     hook = make_dict_structure_fn(C, converter, _cattrs_forbid_extra_keys=False)
     converter.register_structure_hook(C, hook)
     converter.structure(unstructured, A)
     # but we should still raise at the top level
     unstructured["b"] = 6
-    with pytest.raises(ForbiddenExtraKeysError):
+    with pytest.raises(ClassValidationError) as cve:
         converter.structure(unstructured, A)
 
+    assert len(cve.value.exceptions) == 1
+    assert isinstance(cve.value.exceptions[0], ForbiddenExtraKeysError)
+    assert cve.value.exceptions[0].cl is A
+    assert cve.value.exceptions[0].extra_fields == {"b"}
+
 
 @given(nested_typed_classes(defaults=True, min_attrs=1), unstructure_strats, booleans())
 def test_nested_roundtrip(cls_and_vals, strat, omit_if_default):

tests/test_gen_dict.py

@@ -7,7 +7,7 @@
 
 from cattr._compat import adapted_fields, fields
 from cattrs import Converter
-from cattrs.errors import ForbiddenExtraKeysError
+from cattrs.errors import ClassValidationError, ForbiddenExtraKeysError
 from cattrs.gen import make_dict_structure_fn, make_dict_unstructure_fn, override
 
 from . import nested_classes, simple_classes
@@ -227,9 +227,15 @@ class A:
 
     assert new_inst == A(1, "str")
 
-    with pytest.raises(ForbiddenExtraKeysError):
+    with pytest.raises(ClassValidationError) as cve:
         converter.structure({"b": 1, "c": "str"}, A)
 
+    assert len(cve.value.exceptions) == 2
+    assert isinstance(cve.value.exceptions[0], KeyError)
+    assert isinstance(cve.value.exceptions[1], ForbiddenExtraKeysError)
+    assert cve.value.exceptions[1].cl is A
+    assert cve.value.exceptions[1].extra_fields == {"c"}
+
 
 def test_omitting():
     converter = Converter()