fix __post_init__ cause infinite recursion in inheritance

HISTORY.rst

@@ -3,6 +3,10 @@
 History
 -------
 
+v0.30 (unreleased)
+..................
+* fix infinite recursion with dataclass inheritance and ``__post_init__``, #606 by @Hanaasagi
+
 v0.29 (2019-06-19)
 ..................
 * support dataclasses.InitVar, #592 by @pfrederiks

pydantic/dataclasses.py

@@ -13,8 +13,6 @@
 
     class DataclassType:
         __pydantic_model__: Type[BaseModel]
-        __post_init_original__: Callable[..., None]
-        __post_init_post_parse__: Callable[..., None]
         __initialised__: bool
 
         def __init__(self, *args: Any, **kwargs: Any) -> None:
@@ -25,16 +23,6 @@ def __validate__(cls, v: Any) -> 'DataclassType':
             pass
 
 
-def _pydantic_post_init(self: 'DataclassType', *initvars: Any) -> None:
-    if self.__post_init_original__:
-        self.__post_init_original__(*initvars)
-    d = validate_model(self.__pydantic_model__, self.__dict__, cls=self.__class__)[0]
-    object.__setattr__(self, '__dict__', d)
-    object.__setattr__(self, '__initialised__', True)
-    if self.__post_init_post_parse__:
-        self.__post_init_post_parse__()
-
-
 def _validate_dataclass(cls: Type['DataclassType'], v: Any) -> 'DataclassType':
     if isinstance(v, cls):
         return v
@@ -75,15 +63,23 @@ def _process_class(
     post_init_post_parse = getattr(_cls, '__post_init_post_parse__', None)
     if post_init_original and post_init_original.__name__ == '_pydantic_post_init':
         post_init_original = None
+
+    def _pydantic_post_init(self: 'DataclassType', *initvars: Any) -> None:
+        if post_init_original is not None:
+            post_init_original(self, *initvars)
+        d = validate_model(self.__pydantic_model__, self.__dict__, cls=self.__class__)[0]
+        object.__setattr__(self, '__dict__', d)
+        object.__setattr__(self, '__initialised__', True)
+        if post_init_post_parse is not None:
+            post_init_post_parse(self)
+
     _cls.__post_init__ = _pydantic_post_init
     cls = dataclasses._process_class(_cls, init, repr, eq, order, unsafe_hash, frozen)  # type: ignore
 
     fields: Dict[str, Any] = {
         field.name: (field.type, field.default if field.default != dataclasses.MISSING else Required)
         for field in dataclasses.fields(cls)
     }
-    cls.__post_init_original__ = post_init_original
-    cls.__post_init_post_parse__ = post_init_post_parse
 
     validators = gather_validators(cls)
     cls.__pydantic_model__ = create_model(

tests/test_dataclasses.py

@@ -108,6 +108,34 @@ def __post_init__(self):
     assert post_init_called
 
 
+def test_post_init_inheritance_chain():
+    parent_post_init_called = False
+    post_init_called = False
+
+    @pydantic.dataclasses.dataclass
+    class ParentDataclass:
+        a: int
+
+        def __post_init__(self):
+            nonlocal parent_post_init_called
+            parent_post_init_called = True
+
+    @pydantic.dataclasses.dataclass
+    class MyDataclass(ParentDataclass):
+        b: int
+
+        def __post_init__(self):
+            super().__post_init__()
+            nonlocal post_init_called
+            post_init_called = True
+
+    d = MyDataclass(a=1, b=2)
+    assert d.a == 1
+    assert d.b == 2
+    assert parent_post_init_called
+    assert post_init_called
+
+
 def test_post_init_post_parse():
     post_init_post_parse_called = False