Support TypedDict field as Dict[str, Any]

Author: leameow

changelog.d/237.change.rst

@@ -0,0 +1 @@
+Add `TypedDict` subclass support to fields. These are treated the same as `Dict[str, Any]`.

src/desert/_make.py

@@ -305,11 +305,18 @@ def field_for_schema(
         field = field_for_schema(newtype_supertype, default=default)
 
     # enumerations
-    if type(typ) is enum.EnumMeta:
+    elif type(typ) is enum.EnumMeta:
         import marshmallow_enum
 
         field = marshmallow_enum.EnumField(typ, metadata=metadata)
 
+    # TypedDict
+    elif _is_typeddict(typ):
+        field = marshmallow.fields.Dict(
+            keys=marshmallow.fields.String,
+            values=marshmallow.fields.Raw,
+        )
+
     # Nested dataclasses
     forward_reference = getattr(typ, "__forward_arg__", None)
 
@@ -370,6 +377,18 @@ def _get_field_default(
         raise TypeError(field)
 
 
+def _is_typeddict(typ: t.Any) -> bool:
+    # typing_inspect misses some case.
+    # python>=3.10: use t.is_typeddict
+    if hasattr(t, "is_typeddict"):
+        return t.is_typeddict(typ)
+    # python>=3.8; <3.10: Reimplement t.is_typeddict
+    if hasattr(t, "_TypedDictMeta"):
+        return isinstance(typ, t._TypedDictMeta)  # type: ignore[attr-defined]
+    # Fallback to typing_inspect
+    return typing_inspect.typed_dict_keys(typ) is not None
+
+
 @attr.frozen
 class _DesertSentinel:
     pass

tests/test_make.py

@@ -45,6 +45,14 @@ def dataclass_param(request: _pytest.fixtures.SubRequest) -> DataclassModule:
     return module
 
 
+@pytest.fixture
+def typeddict() -> None:
+    try:
+        from typing import TypedDict
+    except ImportError:
+        raise pytest.skip("No TypedDict support")
+
+
 class AssertLoadDumpProtocol(typing_extensions.Protocol):
     def __call__(
         self, schema: marshmallow.Schema, loaded: t.Any, dumped: t.Dict[t.Any, t.Any]
@@ -437,6 +445,27 @@ class A:
     assert_dump_load(schema=schema, loaded=loaded, dumped=dumped)
 
 
+def test_typeddict(
+    module: DataclassModule,
+    assert_dump_load: AssertLoadDumpProtocol,
+    typeddict: None,
+) -> None:
+    """Test dataclasses with basic TypedDict support"""
+
+    class B(t.TypedDict):
+        x: int
+
+    @module.dataclass
+    class A:
+        x: B
+
+    schema = desert.schema_class(A)()
+    dumped = {"x": {"x": 1}}
+    loaded = A(x={"x": 1})  # type: ignore[call-arg]
+
+    assert_dump_load(schema=schema, loaded=loaded, dumped=dumped)
+
+
 @pytest.mark.xfail(
     strict=True,
     reason=(