feat: support annotation with Constraints (#411)

polyfactory/field_meta.py

@@ -3,7 +3,7 @@
 from dataclasses import asdict, is_dataclass
 from typing import TYPE_CHECKING, Any, Literal, Pattern, TypedDict, cast
 
-from typing_extensions import get_args, get_origin
+from typing_extensions import Mapping, get_args, get_origin
 
 from polyfactory.collection_extender import CollectionExtender
 from polyfactory.constants import (
@@ -183,6 +183,10 @@ def parse_constraints(cls, metadata: list[Any]) -> "Constraints":
                     constraints["pattern"] = "[[:digit:]]"
             elif is_dataclass(value) and (value_dict := asdict(value)) and ("allowed_schemes" in value_dict):
                 constraints["url"] = {k: v for k, v in value_dict.items() if v is not None}
+            # This is to support `Constraints`, but we can't do a isinstance with `Constraints` since isinstance
+            # checks with `TypedDict` is not supported.
+            elif isinstance(value, Mapping):
+                constraints.update(value)
             else:
                 constraints.update(
                     {

tests/constraints/test_get_field_value_constraints.py

@@ -4,6 +4,7 @@
 from typing import FrozenSet, List, Set, Tuple, Type, Union, cast
 
 import pytest
+from typing_extensions import Annotated
 
 from polyfactory.factories.base import BaseFactory
 from polyfactory.field_meta import Constraints, FieldMeta
@@ -57,3 +58,11 @@ def test_date() -> None:
 
     assert value >= ge_date
     assert value <= le_date
+
+
+def test_constraints_parsing() -> None:
+    constraints = Constraints(min_length=10)
+    annotation = Annotated[str, constraints]
+    field_meta = FieldMeta.from_type(annotation)
+
+    assert field_meta.constraints == constraints