Add the NoneType hook in type_def (#8)

* add support for expanding signiture list to its base classes when **kwargs is contained in a construction method

* remove fixed FIXME comment

* add a switch to turn off the inherent signature function

* disable the inherent function by default and fix a bug in register.get(), where an unexpected exception may be raised

* add more tests for better code coverage

* fix typos

* add typedef hook for NoneType

* enable full test in test_config_type_def

* remove redundant test call

---------

Co-authored-by: Yansen Wang <[email protected]>

tests/test_config_type_def.py

@@ -22,6 +22,16 @@ def test_any():
     assert TypeDef.dump(typing.Any, '456') == '456'
 
 
+def test_none():
+    assert TypeDef.load(type(None), None) == None
+    assert TypeDef.dump(type(None), None) == None
+
+    with pytest.raises(ValidationError, match='must be NoneType'):
+        TypeDef.load(type(None), 1)
+    with pytest.raises(ValidationError, match='Expected None'):
+        TypeDef.dump(type(None), "123")
+
+
 def test_unsupported_type():
     with pytest.raises(TypeError, match=r'.*Callable\[\[\], str\].*'):
         TypeDef.load(typing.Callable[[], str], lambda x: x)
@@ -197,6 +207,29 @@ class Foo:
     assert TypeDef.dump(typing.Union[pathlib.Path, None], None) == None
 
 
+def test_complex_optional_union():
+    @dataclass
+    class Foo:
+        bar: int = 1
+
+    assert TypeDef.load(typing.Optional[typing.Union[pathlib.Path, Foo]], '/bin') == pathlib.Path('/bin')
+    assert TypeDef.load(typing.Optional[typing.Union[pathlib.Path, Foo]], {'bar': 2}).bar == 2
+    assert TypeDef.load(typing.Optional[typing.Union[pathlib.Path, Foo]], None) == None
+
+    assert TypeDef.load(typing.Union[pathlib.Path, Foo, type(None)], None) == None
+    with pytest.raises(ValidationError, match='are exhausted'):
+        TypeDef.load(typing.Union[pathlib.Path, Foo, type(None)], [1, 2.5, '3'])
+
+    with pytest.raises(ValidationError, match='are exhausted'):
+        TypeDef.dump(typing.Union[pathlib.Path, Foo, type(None)], "/bin")
+
+    assert TypeDef.dump(typing.Optional[typing.Union[pathlib.Path, str]], '/bin') == '/bin'
+    assert TypeDef.dump(typing.Optional[typing.Union[pathlib.Path, Foo]], Foo(bar=2))['bar'] == 2
+    assert TypeDef.dump(typing.Optional[typing.Union[pathlib.Path, Foo]], None) == None
+
+    assert TypeDef.dump(typing.Union[pathlib.Path, Foo, type(None)], None) == None
+
+
 def test_class_config():
     class module:
         def __init__(self, a, b, c=1):
@@ -259,3 +292,4 @@ def __init__(self, a: typing.Union[submodule, ClassConfig[submodule]],
                         {'a': {'a': 1, 'b': 2}, 'b': {'a': 3, 'b': 4, 'c': 5}}).b.c == 5
     assert TypeDef.load(ClassConfig[module],
                         {'a': {'a': 1, 'b': 2}, 'b': {'a': 3, 'b': 4, 'c': 5}}).build().b._c == 5
+

utilsd/config/type_def.py

@@ -209,6 +209,24 @@ def to_plain(self, obj, ctx):
         return obj
 
 
+class NoneTypeDef(TypeDef):
+    @classmethod
+    def new(cls, type_):
+        if type_ is type(None):
+            return cls(type_)
+        return None
+
+    def from_plain(self, plain, ctx):
+        ctx.mark_cli_anchor_point(type(None))
+        return plain
+
+    def to_plain(self, obj, ctx):
+        if obj is None:
+            return None
+        else:
+            raise TypeError(f'Expected None, got {obj}')
+
+
 class OptionalDef(TypeDef):
     @classmethod
     def new(cls, type_):
@@ -660,6 +678,7 @@ def to_plain(self, obj, ctx):
 
 # register all the modules in this file
 TypeDefRegistry.register_module(module=AnyDef)
+TypeDefRegistry.register_module(module=NoneTypeDef)
 TypeDefRegistry.register_module(module=OptionalDef)
 TypeDefRegistry.register_module(module=PathDef)
 TypeDefRegistry.register_module(module=ListDef)