swe_bench / lite / dev

Task input

[version 2.20.0] TypeError: 'NoneType' object is not subscriptable
After update from version 2.19.5 to 2.20.0 I got error for code like:

```python
from marshmallow import Schema, fields, validates


class Bar(Schema):
    value = fields.String()

    @validates('value')  # <- issue here
    def validate_value(self, value):
        pass


class Foo(Schema):
    bar = fields.Nested(Bar)


sch = Foo()

sch.validate({
    'bar': 'invalid',
})
```

```
Traceback (most recent call last):
  File "/_/bug_mschema.py", line 19, in <module>
    'bar': 'invalid',
  File "/_/env/lib/python3.7/site-packages/marshmallow/schema.py", line 628, in validate
    _, errors = self._do_load(data, many, partial=partial, postprocess=False)
  File "/_/env/lib/python3.7/site-packages/marshmallow/schema.py", line 670, in _do_load
    index_errors=self.opts.index_errors,
  File "/_/env/lib/python3.7/site-packages/marshmallow/marshalling.py", line 292, in deserialize
    index=(index if index_errors else None)
  File "/_/env/lib/python3.7/site-packages/marshmallow/marshalling.py", line 65, in call_and_store
    value = getter_func(data)
  File "/_/env/lib/python3.7/site-packages/marshmallow/marshalling.py", line 285, in <lambda>
    data
  File "/_/env/lib/python3.7/site-packages/marshmallow/fields.py", line 265, in deserialize
    output = self._deserialize(value, attr, data)
  File "/_/env/lib/python3.7/site-packages/marshmallow/fields.py", line 465, in _deserialize
    data, errors = self.schema.load(value)
  File "/_/env/lib/python3.7/site-packages/marshmallow/schema.py", line 588, in load
    result, errors = self._do_load(data, many, partial=partial, postprocess=True)
  File "/_/env/lib/python3.7/site-packages/marshmallow/schema.py", line 674, in _do_load
    self._invoke_field_validators(unmarshal, data=result, many=many)
  File "/_/env/lib/python3.7/site-packages/marshmallow/schema.py", line 894, in _invoke_field_validators
    value = data[field_obj.attribute or field_name]
TypeError: 'NoneType' object is not subscriptable
```

Fix tests

tests/test_marshalling.py::TestUnmarshaller::test_deserialize_wrong_nested_type_with_validates_method

Regression tests

tests/test_marshalling.py::test_missing_is_falsy
tests/test_marshalling.py::TestMarshaller::test_prefix
tests/test_marshalling.py::TestMarshaller::test_marshalling_generator
tests/test_marshalling.py::TestMarshaller::test_default_to_missing
tests/test_marshalling.py::TestMarshaller::test_serialize_fields_with_load_only_param
tests/test_marshalling.py::TestMarshaller::test_missing_data_are_skipped
tests/test_marshalling.py::TestMarshaller::test_serialize_with_load_only_doesnt_validate
tests/test_marshalling.py::TestMarshaller::test_serialize_fields_with_dump_to_param
tests/test_marshalling.py::TestMarshaller::test_serialize_fields_with_dump_to_and_prefix_params
tests/test_marshalling.py::TestMarshaller::test_stores_indices_of_errors_when_many_equals_true
tests/test_marshalling.py::TestMarshaller::test_doesnt_store_errors_when_index_errors_equals_false
tests/test_marshalling.py::TestUnmarshaller::test_extra_data_is_ignored
tests/test_marshalling.py::TestUnmarshaller::test_stores_errors
tests/test_marshalling.py::TestUnmarshaller::test_stores_indices_of_errors_when_many_equals_true
tests/test_marshalling.py::TestUnmarshaller::test_doesnt_store_errors_when_index_errors_equals_false
tests/test_marshalling.py::TestUnmarshaller::test_deserialize
tests/test_marshalling.py::TestUnmarshaller::test_extra_fields
tests/test_marshalling.py::TestUnmarshaller::test_deserialize_many
tests/test_marshalling.py::TestUnmarshaller::test_deserialize_stores_errors
tests/test_marshalling.py::TestUnmarshaller::test_deserialize_fields_with_attribute_param
tests/test_marshalling.py::TestUnmarshaller::test_deserialize_fields_with_load_from_param
tests/test_marshalling.py::TestUnmarshaller::test_deserialize_fields_with_dump_only_param
tests/test_marshalling.py::TestUnmarshaller::test_deserialize_wrong_type_root_data
tests/test_marshalling.py::TestUnmarshaller::test_deserialize_wrong_type_nested_data

Scorer detail

[anthropic-agent] Attempt 1: edit 1: search matched 0 times in src/marshmallow/schema.py
[anthropic-agent] Attempt 2: File-rewrite plan contained no files.
[anthropic-agent] Attempt 3: python syntax error in src/marshmallow/schema.py: expected an indented block after 'try' statement on line 893 at line 894
[anthropic-agent] Attempt 4: patch changed too many lines (598); produce a smaller fix

Patch text

{"output": "", "patch_text": "", "stdout": "[anthropic-agent] instance=marshmallow-code__marshmallow-1343\n[anthropic-agent] repo=marshmallow-code/marshmallow\n[anthropic-agent] sandbox=1f0c14f4-3247-45a5-9b1d-cc0fa2096e2d\n[anthropic-agent] model=claude-sonnet-4-20250514\n[anthropic-agent] context_files=5\n[anthropic-agent] full_file_context=yes\n[anthropic-agent] edit_attempts=4", "stderr": "[anthropic-agent] Attempt 1: edit 1: search matched 0 times in src/marshmallow/schema.py\n[anthropic-agent] Attempt 2: File-rewrite plan contained no files.\n[anthropic-agent] Attempt 3: python syntax error in src/marshmallow/schema.py: expected an indented block after 'try' statement on line 893 at line 894\n[anthropic-agent] Attempt 4: patch changed too many lines (598); produce a smaller fix", "model_name": "claude-sonnet-4-20250514", "prompt_tokens": 38437, "completion_tokens": 8882, "reported_cost_usd": 0.248541}

Stdout

[anthropic-agent] instance=marshmallow-code__marshmallow-1343
[anthropic-agent] repo=marshmallow-code/marshmallow
[anthropic-agent] sandbox=1f0c14f4-3247-45a5-9b1d-cc0fa2096e2d
[anthropic-agent] model=claude-sonnet-4-20250514
[anthropic-agent] context_files=5
[anthropic-agent] full_file_context=yes
[anthropic-agent] edit_attempts=4

Stderr

[anthropic-agent] Attempt 1: edit 1: search matched 0 times in src/marshmallow/schema.py
[anthropic-agent] Attempt 2: File-rewrite plan contained no files.
[anthropic-agent] Attempt 3: python syntax error in src/marshmallow/schema.py: expected an indented block after 'try' statement on line 893 at line 894
[anthropic-agent] Attempt 4: patch changed too many lines (598); produce a smaller fix

Agent output

{"output": "", "patch_text": "", "stdout": "[anthropic-agent] instance=marshmallow-code__marshmallow-1343\n[anthropic-agent] repo=marshmallow-code/marshmallow\n[anthropic-agent] sandbox=1f0c14f4-3247-45a5-9b1d-cc0fa2096e2d\n[anthropic-agent] model=claude-sonnet-4-20250514\n[anthropic-agent] context_files=5\n[anthropic-agent] full_file_context=yes\n[anthropic-agent] edit_attempts=4", "stderr": "[anthropic-agent] Attempt 1: edit 1: search matched 0 times in src/marshmallow/schema.py\n[anthropic-agent] Attempt 2: File-rewrite plan contained no files.\n[anthropic-agent] Attempt 3: python syntax error in src/marshmallow/schema.py: expected an indented block after 'try' statement on line 893 at line 894\n[anthropic-agent] Attempt 4: patch changed too many lines (598); produce a smaller fix", "model_name": "claude-sonnet-4-20250514", "prompt_tokens": 38437, "completion_tokens": 8882, "reported_cost_usd": 0.248541}

Passing target tests

No fail-to-pass successes recorded yet.

Failing target tests

No fail-to-pass failures recorded yet.

Maintained regression tests

No pass-to-pass successes recorded yet.

Regressed tests

No regression failures recorded yet.

Harness output

No harness output captured yet.

Reference output

diff --git a/src/marshmallow/schema.py b/src/marshmallow/schema.py
--- a/src/marshmallow/schema.py
+++ b/src/marshmallow/schema.py
@@ -877,7 +877,7 @@ def _invoke_field_validators(self, unmarshal, data, many):
                 for idx, item in enumerate(data):
                     try:
                         value = item[field_obj.attribute or field_name]
-                    except KeyError:
+                    except (KeyError, TypeError):
                         pass
                     else:
                         validated_value = unmarshal.call_and_store(
@@ -892,7 +892,7 @@ def _invoke_field_validators(self, unmarshal, data, many):
             else:
                 try:
                     value = data[field_obj.attribute or field_name]
-                except KeyError:
+                except (KeyError, TypeError):
                     pass
                 else:
                     validated_value = unmarshal.call_and_store(