Add validation field errors (#133)

* Add validation field errors

* Rename test

* Fix join

* Rearrange code

marshmallow_recipe/__init__.py

@@ -30,7 +30,14 @@
 from .naming_case import CAMEL_CASE, CAPITAL_CAMEL_CASE, CamelCase, CapitalCamelCase, NamingCase
 from .options import NoneValueHandling, options
 from .serialization import EmptySchema, dump, dump_many, load, load_many, schema
-from .validation import ValidationFunc, regexp_validate, validate
+from .validation import (
+    ValidationError,
+    ValidationFieldError,
+    ValidationFunc,
+    get_field_errors,
+    regexp_validate,
+    validate,
+)
 
 __all__: tuple[str, ...] = (
     # bake.py
@@ -89,6 +96,9 @@
     "ValidationFunc",
     "regexp_validate",
     "validate",
+    "ValidationError",
+    "ValidationFieldError",
+    "get_field_errors",
 )
 
 __version__ = "0.0.32"

marshmallow_recipe/validation.py

@@ -1,4 +1,5 @@
 import collections.abc
+import dataclasses
 import re
 from typing import Any
 
@@ -22,3 +23,44 @@ def _validator_with_custom_error(value: Any) -> Any:
         return result
 
     return _validator_with_custom_error
+
+
+ValidationError = marshmallow.ValidationError
+
+
+@dataclasses.dataclass(frozen=True, slots=True, kw_only=True)
+class ValidationFieldError:
+    name: str
+    error: str | None = None
+    nested_errors: list["ValidationFieldError"] | None = None
+
+
+def get_field_errors(exc: ValidationError) -> list[ValidationFieldError]:
+    return __get_field_errors_from_normalized_messages(exc.normalized_messages())
+
+
+def __get_field_errors_from_normalized_messages(normalized_messages: dict[Any, Any]) -> list[ValidationFieldError]:
+    field_errors: list[ValidationFieldError] = []
+
+    for key, value in normalized_messages.items():
+        if not isinstance(key, (str, int)):
+            continue
+
+        name = str(key)
+        error: str | None = None
+        nested_errors: list[ValidationFieldError] | None = None
+
+        if isinstance(value, dict):
+            nested_errors = __get_field_errors_from_normalized_messages(value)
+        elif isinstance(value, str):
+            error = value
+        elif isinstance(value, list) and all([isinstance(item, str) for item in value]):
+            error = "; ".join(value)
+        else:
+            continue
+
+        field_errors.append(ValidationFieldError(name=name, error=error, nested_errors=nested_errors))
+
+    field_errors.sort(key=lambda x: x.name)
+
+    return field_errors

tests/test_validation.py

@@ -278,3 +278,40 @@ class IntContainer:
         mr.dump(IntContainer(value=42))
 
     assert exc_info.value.messages == {"value": ["Should be negative."]}
+
+
+def test_get_field_errors() -> None:
+    @dataclasses.dataclass(frozen=True, slots=True, kw_only=True)
+    class NestedContainer:
+        value: int
+        values: list[int]
+
+    @dataclasses.dataclass(frozen=True, slots=True, kw_only=True)
+    class Container:
+        value: int
+        values: list[int]
+        nested: NestedContainer
+
+    with pytest.raises(mr.ValidationError) as exc_info:
+        mr.load(
+            Container,
+            {"value": "invalid", "values": ["invalid"], "nested": {"value": "invalid", "values": ["invalid"]}},
+        )
+
+    assert mr.get_field_errors(exc_info.value) == [
+        mr.ValidationFieldError(
+            name="nested",
+            nested_errors=[
+                mr.ValidationFieldError(name="value", error="Not a valid integer."),
+                mr.ValidationFieldError(
+                    name="values",
+                    nested_errors=[mr.ValidationFieldError(name="0", error="Not a valid integer.")],
+                ),
+            ],
+        ),
+        mr.ValidationFieldError(name="value", error="Not a valid integer."),
+        mr.ValidationFieldError(
+            name="values",
+            nested_errors=[mr.ValidationFieldError(name="0", error="Not a valid integer.")],
+        ),
+    ]