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marshmallow-code/marshmallow

A lightweight library for converting complex objects to and from simple Python datatypes.

30.1 High pattern signal View on GitHub

Maintenance and Governance Review

This report summarizes scanner evidence for marshmallow-code/marshmallow, a Python project with 7,243 GitHub stars. SynthScan examined 16,151 lines of code across 51 source files, recording 547 pattern matches distributed across 10 syntactic categories. The legacy adjusted pattern signal is 30.1 (High pattern signal); it is not an authorship estimate.

Use the findings to ask whether maintainers can explain intent, verify dependencies, simplify unnecessary scaffolding, and focus review effort. Risk Payload v1 adds ownership, supply-chain, over-engineering, and review-effort vectors when available. These are prompts for human verification, not probabilities, security findings, or measured maintenance costs.

30.1
Adjusted Signal
30.1
Raw Pattern Score
100%
Time Factor
2026-10-06
Last Push
7.2K
Stars
Python
Language
16.2K
Lines of Code
51
Files
547
Pattern Hits
2026-10-12
Scan Date
0.10
HC Hit Rate

Risk Review · v3

Use each vector to guide manual verification of the underlying findings.

Cognitive Ownership Risk 72.5/100 · HIGH

Can maintainers explain intent, assumptions, and trade-offs? 499 finding(s).

Hallucinated Dependency & Supply Chain Risk 11.4/100 · LOW

Are imports declared and package/API names verified? 40 finding(s).

Agent Over-Engineering Ratio 74.0/100 · HIGH

Are wrappers, guards, and repeated structures necessary? 497 finding(s).

PR Review Velocity Impact 83.2/100 · CRITICAL

Which changes need focused human review? 547 finding(s).

What These Metrics Mean

Adjusted Signal
Legacy pattern score normalized per 1,000 scanned lines and multiplied by the repository-level time factor. It is not an estimate of AI authorship.
Raw Pattern Score
Sum of severity- and context-weighted pattern findings before applying the time factor.
Time Factor
A coarse multiplier based on repository last-push metadata. It does not identify when individual code was written.
Pattern Hits
Count of configured pattern findings. Review each location and surrounding code before acting.
HC Hit Rate
High- and critical-severity findings per scanned file. Severity is a configured detector weight, not proof of a vulnerability or authorship.
Lines / Files
Scan coverage denominators used by the legacy normalized score.

Pattern-Signal History

This chart tracks the legacy adjusted pattern score across scan runs. Changes can reflect source changes, scan coverage, or detector/scoring versions; they do not measure AI adoption or prove that a team refactored code. Compare runs only when their scoring versions are compatible. The dashed line tracks the raw pattern-hit count.

Severity Breakdown

Groups findings by configured severity weight. Severity is not a confidence estimate, security rating, or proof that a package is missing. Verify imports against the project's manifests and inspect each finding in its local design context.

CRITICAL 0HIGH 5MEDIUM 2LOW 540

Directory Score Breakdown

This horizontal bar chart shows where configured pattern scores accumulate across directories. Treat the bars as locations to inspect, not as evidence of authorship or code quality. Use the file-level findings to decide whether a directory needs a focused ownership, dependency, complexity, or review check.

Pattern Findings

The scanner identified 547 distinct pattern matches across 10 syntactic categories. Each entry below represents a discrete location in the source code where the engine recorded a detector match to inspect in context. Expand any category row to inspect the individual file paths, line numbers, code snippets, and the lexical context (CODE, COMMENT, or STRING) in which each match was detected.

Reading the findings table: The Severity column indicates the configured finding weight (CRITICAL / HIGH / MEDIUM / LOW). The Context column identifies whether the match occurred inside executable code, an inline comment, or a string literal — legacy comment-context matches receive a ×1.5 score weight. The ⚡ bolt icon marks clustered matches: three or more patterns within a 10-line window, each receiving an additional ×1.5 density multiplier under the legacy scoring model.

Hyper-Verbose Identifiers487 hits · 403 pts
SeverityFileLineSnippetContext
LOW⚡tests/test_deserialization.py51 def test_fields_allow_none_deserialize_to_none(self, FieldClass):CODE
LOW⚡tests/test_deserialization.py57 def test_fields_dont_allow_none_by_default(self, FieldClass):CODE
LOW⚡tests/test_deserialization.py62 def test_allow_none_is_true_if_missing_is_true(self):CODE
LOW⚡tests/test_deserialization.py67 def test_list_field_deserialize_none_to_none(self):CODE
LOW⚡tests/test_deserialization.py71 def test_tuple_field_deserialize_none_to_none(self):CODE
LOW⚡tests/test_deserialization.py75 def test_list_of_nested_allow_none_deserialize_none_to_none(self):CODE
LOW⚡tests/test_deserialization.py79 def test_list_of_nested_non_allow_none_deserialize_none_to_validation_error(self):CODE
LOW⚡tests/test_deserialization.py86 def test_float_field_deserialization(self):CODE
LOW⚡tests/test_deserialization.py92 def test_invalid_float_field_deserialization(self, in_val):CODE
LOW⚡tests/test_deserialization.py98 def test_float_field_overflow(self):CODE
LOW⚡tests/test_deserialization.py104 def test_integer_field_deserialization(self):CODE
LOW⚡tests/test_deserialization.py401 def test_boolean_field_deserialization_with_empty_truthy(self):CODE
LOW⚡tests/test_deserialization.py407 def test_boolean_field_deserialization_with_custom_falsy_values(self):CODE
LOW⚡tests/test_deserialization.py412 def test_field_toggle_show_invalid_value_in_error_message(self):CODE
LOW⚡tests/test_deserialization.py595 def test_boolean_timestamp_field_deserialization(self, fmt, in_value):CODE
LOW⚡tests/test_deserialization.py605 def test_invalid_timestamp_field_deserialization(self, fmt, in_value):CODE
LOW⚡tests/test_deserialization.py615 def test_oversized_timestamp_field_deserialization(self, fmt, mock_fromtimestamp):CODE
LOW⚡tests/test_deserialization.py657 def test_naive_datetime_with_timezone(self, fmt, timezone, value, expected):CODE
LOW⚡tests/test_deserialization.py666 def test_aware_datetime_default_timezone(self, fmt, timezone, value):CODE
LOW⚡tests/test_deserialization.py672 def test_time_field_deserialization(self):CODE
LOW⚡tests/test_deserialization.py717 def test_iso_time_field_deserialization(self, fmt, value, expected):CODE
LOW⚡tests/test_deserialization.py724 def test_invalid_timedelta_precision(self):CODE
LOW⚡tests/test_deserialization.py728 def test_timedelta_field_deserialization(self):CODE
LOW⚡tests/test_deserialization.py975 def test_url_field_non_list_validators(self):CODE
LOW⚡tests/test_deserialization.py980 def test_relative_url_field_deserialization(self):CODE
LOW⚡tests/test_deserialization.py984 def test_url_field_schemes_argument(self):CODE
LOW⚡tests/test_deserialization.py992 def test_email_field_deserialization(self):CODE
LOW⚡tests/test_deserialization.py1005 def test_email_field_non_list_validators(self):CODE
LOW⚡tests/test_deserialization.py1010 def test_function_field_deserialization_is_noop_by_default(self):CODE
LOW⚡tests/test_deserialization.py1016 def test_function_field_deserialization_with_callable(self):CODE
LOW⚡tests/test_deserialization.py1020 def test_function_field_deserialization_missing_with_length_validator(self):CODE
LOW⚡tests/test_deserialization.py1027 def test_function_field_passed_deserialize_only_is_load_only(self):CODE
LOW⚡tests/test_deserialization.py1031 def test_function_field_passed_deserialize_and_serialize_is_not_load_only(self):CODE
LOW⚡tests/test_deserialization.py1037 def test_uuid_field_deserialization(self):CODE
LOW⚡tests/test_deserialization.py1200 def test_enum_field_by_symbol_deserialization(self):CODE
LOW⚡tests/test_deserialization.py1204 def test_enum_field_by_symbol_invalid_value(self):CODE
LOW⚡tests/test_deserialization.py1212 def test_enum_field_by_symbol_rejects_non_member_attributes(self, non_member):CODE
LOW⚡tests/test_deserialization.py1219 def test_enum_field_by_symbol_not_string(self):CODE
LOW⚡tests/test_deserialization.py1224 def test_enum_field_by_value_true_deserialization(self):CODE
LOW⚡tests/test_deserialization.py1230 def test_enum_field_by_value_field_deserialization(self):CODE
LOW⚡tests/test_deserialization.py1238 def test_enum_field_by_value_true_invalid_value(self):CODE
LOW⚡tests/test_deserialization.py1287 def test_enum_by_value_allow_none_default(self):CODE
LOW⚡tests/test_deserialization.py1291 def test_deserialization_function_must_be_callable(self):CODE
LOW⚡tests/test_deserialization.py1295 def test_method_field_deserialization_is_noop_by_default(self):CODE
LOW⚡tests/test_deserialization.py1305 def test_deserialization_method(self):CODE
LOW⚡tests/test_deserialization.py1318 def test_deserialization_method_must_be_a_method(self):CODE
LOW⚡tests/test_deserialization.py1325 def test_method_field_deserialize_only(self):CODE
LOW⚡tests/test_deserialization.py1334 def test_datetime_list_field_deserialization(self):CODE
LOW⚡tests/test_deserialization.py1343 def test_list_field_deserialize_invalid_item(self):CODE
LOW⚡tests/test_deserialization.py1415 def test_tuple_field_deserialize_value_that_is_not_a_collection(self, value):CODE
LOW⚡tests/test_deserialization.py1421 def test_tuple_field_deserialize_invalid_length(self):CODE
LOW⚡tests/test_deserialization.py1427 def test_constant_field_deserialization(self):CODE
LOW⚡tests/test_deserialization.py1431 def test_constant_is_always_included_in_deserialized_data(self):CODE
LOW⚡tests/test_deserialization.py1439 def test_constant_none_allows_none_value(self):CODE
LOW⚡tests/test_deserialization.py1448 def test_constant_with_required(self):CODE
LOW⚡tests/test_deserialization.py1456 def test_field_deserialization_with_user_validator_function(self):CODE
LOW⚡tests/test_deserialization.py1464 def test_field_deserialization_with_user_validator_that_raises_error_with_list(CODE
LOW⚡tests/test_deserialization.py1703 def test_nested_none_deserialization(self):CODE
LOW⚡tests/test_deserialization.py1713 def test_deserialize_with_attribute_param(self):CODE
LOW⚡tests/test_deserialization.py1724 def test_deserialize_with_attribute_param_symmetry(self):CODE
427 more matches not shown…
Unused Imports29 hits · 29 pts
SeverityFileLineSnippetContext
LOWtests/test_registry.py192CODE
LOWtests/test_registry.py207CODE
LOWtests/test_registry.py214CODE
LOWtests/test_utils.py1CODE
LOWtests/mypy_test_cases/test_validation_error.py1CODE
LOWexamples/flask_example.py10CODE
LOWsrc/marshmallow/fields.py2CODE
LOWsrc/marshmallow/__init__.py1CODE
LOWsrc/marshmallow/__init__.py1CODE
LOWsrc/marshmallow/__init__.py1CODE
LOWsrc/marshmallow/__init__.py1CODE
LOWsrc/marshmallow/__init__.py2CODE
LOWsrc/marshmallow/__init__.py2CODE
LOWsrc/marshmallow/__init__.py2CODE
LOWsrc/marshmallow/__init__.py2CODE
LOWsrc/marshmallow/__init__.py2CODE
LOWsrc/marshmallow/__init__.py2CODE
LOWsrc/marshmallow/__init__.py10CODE
LOWsrc/marshmallow/__init__.py11CODE
LOWsrc/marshmallow/__init__.py11CODE
LOWsrc/marshmallow/__init__.py13CODE
LOWsrc/marshmallow/types.py8CODE
LOWsrc/marshmallow/validate.py3CODE
LOWsrc/marshmallow/class_registry.py12CODE
LOWsrc/marshmallow/utils.py3CODE
LOWsrc/marshmallow/exceptions.py3CODE
LOWsrc/marshmallow/schema.py4CODE
LOWsrc/marshmallow/decorators.py68CODE
LOWsrc/marshmallow/experimental/context.py31CODE
Empty Error Handlers5 hits · 25 pts
SeverityFileLineSnippetContext
HIGHsrc/marshmallow/fields.py26except ImportError:CODE
HIGHsrc/marshmallow/validate.py583except TypeError:CODE
HIGHsrc/marshmallow/schema.py189except AttributeError:CODE
HIGHsrc/marshmallow/schema.py1162except KeyError:CODE
HIGHsrc/marshmallow/schema.py1147except KeyError:CODE
Fake / Example Data11 hits · 10 pts
SeverityFileLineSnippetContext
LOW⚡tests/test_deserialization.py994 assert field.deserialize("foo@bar.com") == "foo@bar.com"CODE
LOW⚡tests/test_deserialization.py1001 field.deserialize("foo@bar.com")CODE
LOW⚡tests/test_deserialization.py1718 data = {"username": "foo@bar.com", "years": "42"}CODE
LOW⚡tests/test_deserialization.py1720 assert result["email"] == "foo@bar.com"CODE
LOW⚡tests/test_deserialization.py1769 data = {"Name": "Mick", "UserName": "foo@bar.com", "years": "42"}CODE
LOW⚡tests/test_deserialization.py1772 assert result["email"] == "foo@bar.com"CODE
LOW⚡tests/test_deserialization.py1857 {"email": "foo@bar.com", "colors": "red", "age": 18},CODE
LOW⚡tests/test_schema.py574 "email": "foo@bar.com",CODE
LOWtests/test_validate.py337 "!#$%&'*+-/=?^_`{}|~@example.org",CODE
LOWtests/test_validate.py360 '" "@example.org',CODE
LOW⚡tests/test_serialization.py42 return User("Foo", email="foo@bar.com", age=42)CODE
Deep Nesting7 hits · 6 pts
SeverityFileLineSnippetContext
LOWtests/test_fields.py313CODE
LOWsrc/marshmallow/fields.py567CODE
LOWsrc/marshmallow/fields.py1688CODE
LOWsrc/marshmallow/error_store.py37CODE
LOWsrc/marshmallow/schema.py597CODE
LOWsrc/marshmallow/schema.py773CODE
LOWsrc/marshmallow/schema.py1124CODE
Decorative Section Separators1 hit · 3 pts
SeverityFileLineSnippetContext
MEDIUMexamples/inflection_example.py24# -----------------------------------------------------------------------------COMMENT
Self-Referential Comments1 hit · 3 pts
SeverityFileLineSnippetContext
MEDIUMexamples/flask_example.py144 # Create a new authorCOMMENT
AI Structural Patterns2 hits · 2 pts
SeverityFileLineSnippetContext
LOWtests/base.py104CODE
LOWsrc/marshmallow/fields.py192CODE
Modern Structural Boilerplate2 hits · 2 pts
SeverityFileLineSnippetContext
LOWsrc/marshmallow/fields.py44__all__ = [CODE
LOWsrc/marshmallow/__init__.py15__all__ = [CODE
Over-Commented Block2 hits · 2 pts
SeverityFileLineSnippetContext
LOWsrc/marshmallow/orderedset.py1# OrderedSetCOMMENT
LOWsrc/marshmallow/class_registry.py41 register("MyClass", MyClass)COMMENT