bugfix for dataclass in dict

HISTORY.rst

@@ -2,6 +2,15 @@
 History
 =======
 
+0.32.1 (2024-12-04)
+-------------------
+
+**Bugfixes**
+
+- Corrected logic in :class:`MappingParser` that assumed all parsers were
+  subclasses of :class:`AbstractParser` (:issue:`159`).
+    - Add test case to confirm intended functionality.
+
 0.32.0 (2024-11-30)
 -------------------
 

dataclass_wizard/parsers.py

@@ -534,7 +534,7 @@ class MappingParser(AbstractParser[Type[M], M]):
     __slots__ = ('hook',
                  'key_parser',
                  'val_parser',
-                 'val_base_type')
+                 'val_type')
 
     base_type: Type[M]
     hook: Callable[[Any, Type[M], AbstractParser, AbstractParser], M]
@@ -551,12 +551,12 @@ def __post_init__(self, cls: Type,
         # Base type of the object which is instantiable
         #   ex. `Dict[str, Any]` -> `dict`
         self.base_type: Type[M] = get_origin(self.base_type)
+        self.val_type = val_type
 
         val_parser = get_parser(val_type, cls, extras)
 
         self.key_parser = getattr(p := get_parser(key_type, cls, extras), '__call__', p)
         self.val_parser = getattr(val_parser, '__call__', val_parser)
-        self.val_base_type = val_parser.base_type
 
     def __call__(self, o: M) -> M:
         return self.hook(o, self.base_type, self.key_parser, self.val_parser)
@@ -577,7 +577,9 @@ def __post_init__(self, cls: Type,
         super().__post_init__(cls, extras, get_parser)
 
         # The default factory argument to pass to the `defaultdict` subclass
-        self.default_factory: DefFactory = self.val_base_type
+        val_type = self.val_type
+        val_base_type = getattr(val_type, '__origin__', val_type)
+        self.default_factory: DefFactory = val_base_type
 
     def __call__(self, o: DD) -> DD:
         return self.hook(o, self.base_type, self.default_factory,

tests/unit/test_dump.py

@@ -486,3 +486,25 @@ class MyClass(JSONSerializable):
     with expectation:
         result = c.to_dict()
         log.debug('Parsed object: %r', result)
+
+
+def test_using_dataclass_in_dict():
+    """
+    Using dataclass in a dictionary (i.e., dict[str, Test])
+    works as expected.
+
+    See https://github.com/rnag/dataclass-wizard/issues/159
+    """
+    @dataclass
+    class Test:
+        field: str
+
+    @dataclass
+    class Config:
+        tests: dict[str, Test]
+
+    config = {"tests": {"test_a": {"field": "a"}, "test_b": {"field": "b"}}}
+
+    assert fromdict(Config, config) == Config(
+        tests={'test_a': Test(field='a'),
+               'test_b': Test(field='b')})