Bugfix in dataclass when frozen=False; Add docs detailing typing support

docs/index.rst

@@ -7,16 +7,22 @@ Welcome to Runtype's documentation!
 ===================================
 
 .. toctree::
-   :maxdepth: 2
    :caption: Modules
+   :maxdepth: 2
    :hidden:
 
    validation
    dataclass
    dispatch
    types
-   benchmarks
 
+.. toctree::
+   :caption: Overview
+   :maxdepth: 2
+   :hidden:
+
+   typing_support
+   benchmarks
 
 Runtype is a collection of run-time type utilities for Python.
 

docs/typing_support.rst

@@ -0,0 +1,64 @@
+Typing support
+==============
+
+Runtype supports a wide-range of types and typing constructs, however full-support is still work in progress.
+
+For now, some constructs are available for validation, but not for dispatch.
+
+Here is the detailed list:
+
+.. list-table::
+   :widths: 25 25 25
+   :header-rows: 1
+
+   * - Types / Constructs
+     - Validation
+     - Dispatch
+   * - Primitives (None, bool, float, int, str, etc.)
+     - ✔
+     - ✔
+   * - Date primitives (datetime, date, time, timedelta)
+     - ✔
+     - ✔
+   * - Containers, non-generic  (list, tuple, dict)
+     - ✔
+     - ✔
+   * - Callable, non-generic (callable)
+     - ✔
+     - ✔
+   * - abc.Set, abc.MutableMapping, etc.
+     - ✔
+     - ✔
+   * - typing.AbstractSet
+     - ✔
+     - ✔
+   * - typing.Any
+     - ✔
+     - ✔
+   * - typing.Union, Optional
+     - ✔
+     - ✔
+   * - typing.Type (Type[x])
+     - ✔
+     - ✔
+   * - typing.Literal
+     - ✔
+     - ✔
+   * - Generic containers (list[x], tuple[x], dict[x])
+     - ✔
+     - TODO
+   * - Infinite tuple (tuple[x, ...])
+     - ✔
+     - TODO
+   * - Generic callable
+     - TODO
+     - TODO
+   * - typing.IO
+     - TODO
+     - TODO
+   * - TypeVar
+     - TODO
+     - TODO
+   * - Protocol
+     - TODO
+     - TODO

runtype/dataclass.py

@@ -24,6 +24,7 @@ def dataclass_transform(*a, **kw):
 from .pytypes import TypeCaster, SumType, NoneType, ATypeCaster, PythonType, type_caster
 
 Required = object()
+Skip = object()
 MAX_SAMPLE_SIZE = 16
 
 class NopTypeCaster(ATypeCaster):
@@ -150,6 +151,7 @@ def _validate_attr(config, should_cast, sampler, obj, name, type_, value):
         if item_value is not value:
             msg += f'\n\n    Failed on item: {item_value!r}, expected type {item_type}'
         raise TypeError(msg)
+    return Skip
 
 def _post_init(self, config, should_cast, sampler, type_caster):
     for name, field in getattr(self, '__dataclass_fields__', {}).items():
@@ -160,7 +162,7 @@ def _post_init(self, config, should_cast, sampler, type_caster):
 
         type_ = _get_field_type(type_caster, field)
         new_value = _validate_attr(config, should_cast, sampler, self, name, type_, value)
-        if new_value is not None:
+        if new_value is not Skip:
             object.__setattr__(self, name, new_value)
 
 def _post_init__no_check_types(self):
@@ -174,11 +176,11 @@ def _setattr(obj, setattr, name, value, config, should_cast, sampler, type_caste
     try:
         field = obj.__dataclass_fields__[name]
     except (KeyError, AttributeError):
-        new_value = None
+        new_value = Skip
     else:
         type_ = _get_field_type(type_caster, field)
         new_value = _validate_attr(config, should_cast, sampler, obj, name, type_, value)
-    setattr(obj, name, value if new_value is None else new_value)
+    setattr(obj, name, value if new_value is Skip else new_value)
 
 
 def replace(inst, **kwargs):

tests/test_basic.py

@@ -890,6 +890,16 @@ class A:
         else:
             assert False
 
+    def test_unfrozen2(self):
+        @dataclass(frozen=False)
+        class A:
+            a: list = None
+
+        a = A([1,2])
+        assert a.a == [1,2]
+        a.a = None
+        assert a.a is None
+
     def test_frozen(self):
         @dataclass
         class A:

tests/test_casts.py

@@ -159,3 +159,24 @@ class Person:
             bla: int = None
 
         assert Person("Albert Einstein") == Person(('Albert', 'Einstein'), None) == Person(['Albert', 'Einstein'])
+
+    def test_cast_in_unfrozen(self):
+        @dataclass
+        class CastToNone:
+            @classmethod
+            def cast_from(cls, c: str):
+                if c == 'none':
+                    return None
+                return c
+
+        @dataclass(check_types='cast', frozen=False)
+        class A:
+            s: CastToNone
+
+        assert A('hello').s == 'hello'
+        assert A('none').s is None
+        a = A('hello') 
+        a.s = 'bla'
+        assert a.s == 'bla'
+        a.s = None
+        assert a.s is None