Merge pull request #157 from modern-python/fix-required-but-missing-context

raise error for required but missing context

Author: lesnik512

modern_di/providers/context_provider.py

@@ -10,10 +10,16 @@
 
 
 class ContextProvider(AbstractProvider[types.T_co]):
-    __slots__ = AbstractProvider.BASE_SLOTS
-
-    def __init__(self, *, scope: Scope = Scope.APP, context_type: type[types.T_co]) -> None:
-        super().__init__(scope=scope, bound_type=context_type)
+    __slots__ = [*AbstractProvider.BASE_SLOTS, "_context_type"]
+
+    def __init__(
+        self,
+        *,
+        scope: Scope = Scope.APP,
+        context_type: type[types.T_co],
+        bound_type: type | None = types.UNSET,  # type: ignore[assignment]
+    ) -> None:
+        super().__init__(scope=scope, bound_type=bound_type if bound_type != types.UNSET else context_type)
 
     def validate(self, container: "Container") -> dict[str, typing.Any]:  # noqa: ARG002
         return {"bound_type": self.bound_type, "self": self}

modern_di/providers/factory.py

@@ -3,6 +3,7 @@
 import typing
 
 from modern_di import errors, types
+from modern_di.providers import ContextProvider
 from modern_di.providers.abstract import AbstractProvider
 from modern_di.scope import Scope
 from modern_di.types_parser import SignatureItem, parse_creator
@@ -63,11 +64,18 @@ def _compile_kwargs(self, container: "Container") -> dict[str, typing.Any]:
                     if provider:
                         break
 
+            is_kwarg_not_found = not self._kwargs or k not in self._kwargs
             if provider:
                 result[k] = provider
+                if is_kwarg_not_found and isinstance(provider, ContextProvider) and provider.resolve(container) is None:
+                    raise RuntimeError(
+                        errors.FACTORY_ARGUMENT_RESOLUTION_ERROR.format(
+                            arg_name=k, arg_type=v.arg_type, bound_type=self.bound_type or self._creator
+                        )
+                    )
                 continue
 
-            if (not self._kwargs or k not in self._kwargs) and v.default == types.UNSET:
+            if v.default == types.UNSET and is_kwarg_not_found:
                 raise RuntimeError(
                     errors.FACTORY_ARGUMENT_RESOLUTION_ERROR.format(
                         arg_name=k, arg_type=v.arg_type, bound_type=self.bound_type or self._creator

tests/providers/test_context_provider.py

@@ -1,33 +1,51 @@
+import dataclasses
 import datetime
 
-from modern_di import Container, Scope, providers
+import pytest
+
+from modern_di import Container, Group, Scope, providers
 
 
-context_provider = providers.ContextProvider(scope=Scope.APP, context_type=datetime.datetime)
 request_context_provider = providers.ContextProvider(scope=Scope.REQUEST, context_type=datetime.datetime)
 
 
+@dataclasses.dataclass(kw_only=True, slots=True, frozen=True)
+class SomeFactory:
+    arg1: datetime.datetime
+
+
+class MyGroup(Group):
+    context_provider = providers.ContextProvider(scope=Scope.APP, context_type=datetime.datetime)
+    some_factory = providers.Factory(creator=SomeFactory)
+
+
 def test_context_provider() -> None:
     now = datetime.datetime.now(tz=datetime.timezone.utc)
     app_container = Container(context={datetime.datetime: now})
-    app_container.validate_provider(context_provider)
-    instance1 = app_container.resolve_provider(context_provider)
-    instance2 = app_container.resolve_provider(context_provider)
+    app_container.validate_provider(MyGroup.context_provider)
+    instance1 = app_container.resolve_provider(MyGroup.context_provider)
+    instance2 = app_container.resolve_provider(MyGroup.context_provider)
     assert instance1 is instance2 is now
 
 
 def test_context_provider_set_context_after_creation() -> None:
     now = datetime.datetime.now(tz=datetime.timezone.utc)
     app_container = Container()
     app_container.set_context(datetime.datetime, now)
-    instance1 = app_container.resolve_provider(context_provider)
-    instance2 = app_container.resolve_provider(context_provider)
+    instance1 = app_container.resolve_provider(MyGroup.context_provider)
+    instance2 = app_container.resolve_provider(MyGroup.context_provider)
     assert instance1 is instance2 is now
 
 
 def test_context_provider_not_found() -> None:
     app_container = Container()
-    assert app_container.resolve_provider(context_provider) is None
+    assert app_container.resolve_provider(MyGroup.context_provider) is None
+
+
+def test_context_provider_not_found_but_required() -> None:
+    app_container = Container(groups=[MyGroup])
+    with pytest.raises(RuntimeError, match=r"Argument arg1 of type <class 'datetime.datetime'> cannot be resolved"):
+        app_container.resolve(SomeFactory)
 
 
 def test_context_provider_in_request_scope() -> None: