Merge pull request #72 from altescy/modify-lazy-constructor-prop

Return lazy constructor by tracing registrable

colt/builder.py

@@ -131,6 +131,26 @@ def _catname(parent: str, *keys: Union[int, str]) -> str:
         key = ".".join(str(x) for x in keys)
         return f"{parent}.{key}" if parent else key
 
+    def _get_constructor(
+        self,
+        config: Any,
+        param_name: str,
+        annotation: Optional[Union[Type[T], Callable[..., T]]] = None,
+    ) -> Optional[Union[Type[T], Callable[..., T]]]:
+        if not isinstance(config, Mapping):
+            return None
+        if self._typekey not in config:
+            return None
+        name = config[self._typekey]
+        if not isinstance(name, str):
+            return None
+        return self._get_constructor_by_name(
+            name,
+            param_name,
+            annotation,
+            allow_to_import=not self._strict,
+        )
+
     def _construct_args(
         self,
         constructor: Callable[..., T],

colt/lazy.py

@@ -1,6 +1,16 @@
 import typing
 from copy import deepcopy
-from typing import Any, Generic, Mapping, Optional, Sequence, Type, TypeVar, Union
+from typing import (
+    Any,
+    Callable,
+    Generic,
+    Mapping,
+    Optional,
+    Sequence,
+    Type,
+    TypeVar,
+    Union,
+)
 
 from colt.utils import update_field
 
@@ -32,8 +42,11 @@ def config(self) -> Any:
         return self._config
 
     @property
-    def constructor(self) -> Optional[Type[T]]:
-        return self._cls
+    def constructor(self) -> Optional[Union[Type[T], Callable[..., T]]]:
+        return (
+            self._builder._get_constructor(self._config, self._param_name, self._cls)
+            or self._cls
+        )
 
     def update(
         self,

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "colt"
-version = "0.13.0"
+version = "0.13.1"
 description = "A configuration utility for Python object."
 authors = ["altescy <altescy@fastmail.com>"]
 license = "MIT License"

tests/test_lazy.py

@@ -3,7 +3,7 @@
 import pytest
 
 import colt
-from colt import ConfigurationError, Lazy
+from colt import ConfigurationError, Lazy, Registrable
 
 
 def test_lazy() -> None:
@@ -49,3 +49,32 @@ class Bar:
 
     with pytest.raises(ConfigurationError):
         bar.foo.update(name=123)
+
+
+def test_lazy_constructor() -> None:
+    @dataclasses.dataclass
+    class Foo:
+        name: str
+
+    @dataclasses.dataclass
+    class Bar:
+        foo: Lazy[Foo]
+
+    bar = colt.build({"foo": {"name": "foo"}}, Bar)
+
+    assert bar.foo.constructor == Foo
+
+
+def test_lazy_constructor_with_registrable() -> None:
+    class Foo(Registrable): ...
+
+    @Foo.register("bar")
+    class Bar(Foo): ...
+
+    @dataclasses.dataclass
+    class Baz:
+        foo: Lazy[Foo]
+
+    baz = colt.build({"foo": {"@type": "bar"}}, Baz)
+
+    assert baz.foo.constructor == Bar

tests/test_version.py

@@ -2,4 +2,4 @@
 
 
 def test_version() -> None:
-    assert colt.__version__ == "0.13.0"
+    assert colt.__version__ == "0.13.1"