Merge pull request #277 from IvanKirpichnikov/override-provides

add override for alias and from context

docs/provider/alias.rst

@@ -18,4 +18,19 @@ Provider object has also a ``.alias`` method with the same logic.
 
         a_proto = alias(source=A, provides=AProtocol)
 
-Additionally, alias has own setting for caching: it caches by default regardless if source is cached. You can disable it providing ``cache=False`` argument.
+Additionally, alias has own setting for caching: it caches by default regardless if source is cached. You can disable it providing ``cache=False`` argument.
+
+* Do you want to override the alias? To do this, specify the parameter ``override=True``. This can be checked when passing proper ``validation_settings`` when creating container.
+
+.. code-block:: python
+
+    from dishka import WithParents, provide, Provider, Scope, alias
+    class MyProvider(Provider):
+        scope=Scope.APP
+        a = provide(lambda: 1, provides=int)
+        a_alias = alias(float, provides=int)
+        a_alias_override = alias(float, provides=int, override=True)
+
+    container = make_async_container(MyProvider())
+    a = await container.get(int)
+    # 2

docs/provider/from_context.rst

@@ -23,3 +23,18 @@ You can put some data manually when entering scope and rely on it in your provid
     container = make_container(MyProvider(), context={App: app})
     with container(context={RequestClass: request_instance}) as request_container:
         pass
+
+
+* Do you want to override the from_context? To do this, specify the parameter ``override=True``. This can be checked when passing proper ``validation_settings`` when creating container.
+
+.. code-block:: python
+
+    from dishka import WithParents, from_context, Provider, Scope
+    class MyProvider(Provider):
+        scope=Scope.APP
+        a = from_context(provides=int)
+        a_override = from_context(provides=int, override=True)
+
+    container = make_async_container(MyProvider())
+    a = await container.get(int)
+    # 2

src/dishka/dependency_source/alias.py

@@ -14,17 +14,19 @@ def _identity(x: Any) -> Any:
 
 
 class Alias:
-    __slots__ = ("source", "provides", "cache", "component")
+    __slots__ = ("source", "provides", "cache", "component", "override")
 
     def __init__(
             self, *,
             source: DependencyKey,
             provides: DependencyKey,
             cache: bool,
+            override: bool,
     ) -> None:
         self.source = source
         self.provides = provides
         self.cache = cache
+        self.override = override
 
     def as_factory(
             self, scope: BaseScope | None, component: Component | None,
@@ -38,7 +40,7 @@ def as_factory(
             kw_dependencies={},
             type_=FactoryType.ALIAS,
             cache=self.cache,
-            override=False,
+            override=self.override,
         )
 
     def __get__(self, instance: Any, owner: Any) -> Alias:

src/dishka/dependency_source/context_var.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from typing import Any
+from typing import Any, NoReturn
 
 from dishka.entities.component import DEFAULT_COMPONENT, Component
 from dishka.entities.factory_type import FactoryType
@@ -10,20 +10,22 @@
 from .factory import Factory
 
 
-def context_stub() -> Any:
+def context_stub() -> NoReturn:
     raise NotImplementedError
 
 
 class ContextVariable:
-    __slots__ = ("provides", "scope")
+    __slots__ = ("provides", "scope", "override")
 
     def __init__(
             self, *,
             provides: DependencyKey,
             scope: BaseScope | None,
+            override: bool,
     ) -> None:
         self.provides = provides
         self.scope = scope
+        self.override = override
 
     def as_factory(
             self, component: Component,
@@ -38,14 +40,17 @@ def as_factory(
                 kw_dependencies={},
                 type_=FactoryType.CONTEXT,
                 cache=False,
-                override=False,
+                override=self.override,
             )
         else:
             aliased = Alias(
                 source=self.provides.with_component(DEFAULT_COMPONENT),
-                provides=DependencyKey(self.provides.type_hint,
-                                       component=component),
                 cache=False,
+                override=self.override,
+                provides=DependencyKey(
+                    component=component,
+                    type_hint=self.provides.type_hint,
+                ),
             )
             return aliased.as_factory(scope=self.scope, component=component)
 
@@ -54,4 +59,5 @@ def __get__(self, instance: Any, owner: Any) -> ContextVariable:
         return ContextVariable(
             scope=scope,
             provides=self.provides,
+            override=self.override,
         )

src/dishka/dependency_source/make_alias.py

@@ -13,6 +13,7 @@ def alias(
         provides: Any | None = None,
         cache: bool = True,
         component: Component | None = None,
+        override: bool = False,
 ) -> CompositeDependencySource:
     if component is provides is None:
         raise ValueError("Either component or provides must be set in alias")
@@ -27,6 +28,7 @@ def alias(
         ),
         provides=DependencyKey(provides, None),
         cache=cache,
+        override=override,
     )
     composite.dependency_sources.extend(unpack_alias(alias_instance))
     return composite

src/dishka/dependency_source/make_context_var.py

@@ -8,16 +8,20 @@
 
 
 def from_context(
-        provides: Any, *, scope: BaseScope | None = None,
+        provides: Any,
+        *,
+        scope: BaseScope | None = None,
+        override: bool = False,
 ) -> CompositeDependencySource:
     composite = CompositeDependencySource(origin=context_stub)
     composite.dependency_sources.append(
         ContextVariable(
+            scope=scope,
+            override=override,
             provides=DependencyKey(
                 type_hint=provides,
                 component=DEFAULT_COMPONENT,
             ),
-            scope=scope,
         ),
     )
     return composite

src/dishka/dependency_source/unpack_provides.py

@@ -19,6 +19,7 @@ def unpack_factory(factory: Factory) -> Sequence[DependencySource]:
             provides=DependencyKey(provides_other, factory.provides.component),
             source=DependencyKey(provides_first, factory.provides.component),
             cache=factory.cache,
+            override=factory.override,
         )
         for provides_other in provides_others
     ]
@@ -63,6 +64,7 @@ def unpack_alias(alias: Alias) -> Sequence[DependencySource]:
             provides=DependencyKey(provides, alias.provides.component),
             source=alias.source,
             cache=alias.cache,
+            override=alias.override,
         )
         for provides in alias.provides.type_hint.items
     ]

src/dishka/provider.py

@@ -163,7 +163,10 @@ def provide_all(
         if scope is None:
             scope = self.scope
         composite = provide_all_on_instance(
-            *provides, scope=scope, cache=cache, recursive=recursive,
+            *provides,
+            scope=scope,
+            cache=cache,
+            recursive=recursive,
             override=override,
         )
         self._add_dependency_sources("?", composite.dependency_sources)
@@ -176,12 +179,14 @@ def alias(
             provides: Any = None,
             cache: bool = True,
             component: Component | None = None,
+            override: bool = False,
     ) -> CompositeDependencySource:
         composite = alias(
             source=source,
             provides=provides,
             cache=cache,
             component=component,
+            override=override,
         )
         self._add_dependency_sources(str(source), composite.dependency_sources)
         return composite
@@ -207,10 +212,12 @@ def from_context(
             provides: Any,
             *,
             scope: BaseScope | None = None,
+            override: bool = False,
     ) -> CompositeDependencySource:
         composite = from_context(
             provides=provides,
             scope=scope or self.scope,
+            override=override,
         )
         self._add_dependency_sources(
             name=str(provides),

src/dishka/registry_builder.py

@@ -175,6 +175,7 @@ def _init_registries(self) -> None:
             context_var = ContextVariable(
                 provides=DependencyKey(self.container_type, DEFAULT_COMPONENT),
                 scope=scope,
+                override=False,
             )
             for component in self.components:
                 registry.add_factory(context_var.as_factory(component))
@@ -243,7 +244,27 @@ def _process_alias(
         registry = self.registries[scope]
 
         factory = alias.as_factory(scope, component)
+        if (
+            self.validation_settings.nothing_overridden
+            and not self.skip_validation
+            and factory.override
+            and factory.provides not in self.processed_factories
+        ):
+            raise NothingOverriddenError(factory)
+
+        if (
+            self.validation_settings.implicit_override
+            and not self.skip_validation
+            and not factory.override
+            and factory.provides in self.processed_factories
+        ):
+            raise ImplicitOverrideDetectedError(
+                factory,
+                self.processed_factories[factory.provides],
+            )
+
         self.dependency_scopes[factory.provides] = scope
+        self.processed_factories[factory.provides] = factory
         registry.add_factory(factory)
 
     def _process_generic_decorator(
@@ -375,7 +396,27 @@ def _process_context_var(
             )
         registry = self.registries[context_var.scope]
         for component in self.components:
-            registry.add_factory(context_var.as_factory(component))
+            factory = context_var.as_factory(component)
+            if (
+                self.validation_settings.nothing_overridden
+                and not self.skip_validation
+                and factory.override
+                and factory.provides not in self.processed_factories
+            ):
+                raise NothingOverriddenError(factory)
+
+            if (
+                self.validation_settings.implicit_override
+                and not self.skip_validation
+                and not factory.override
+                and factory.provides in self.processed_factories
+            ):
+                raise ImplicitOverrideDetectedError(
+                    factory,
+                    self.processed_factories[factory.provides],
+                )
+            self.processed_factories[context_var.provides] = factory
+            registry.add_factory(factory)
 
     def build(self) -> tuple[Registry, ...]:
         self._collect_components()

tests/unit/container/override/test_alias.py

@@ -0,0 +1,88 @@
+import pytest
+
+from dishka import Provider, Scope, alias, make_container, provide
+from dishka.entities.validation_settigs import (
+    STRICT_VALIDATION,
+    ValidationSettings,
+)
+from dishka.exceptions import (
+    ImplicitOverrideDetectedError,
+    NothingOverriddenError,
+)
+
+
+def test_no_override() -> None:
+    class TestProvider(Provider):
+        scope = Scope.APP
+        provides = (
+            provide(int, provides=int)
+            + alias(source=int, provides=float)
+            + alias(source=int, provides=float)
+        )
+
+    with pytest.raises(ImplicitOverrideDetectedError) as e:
+        make_container(
+            TestProvider(),
+            validation_settings=STRICT_VALIDATION,
+        )
+    assert str(e.value)
+
+
+def test_skip_no_override() -> None:
+    class TestProvider(Provider):
+        scope = Scope.APP
+        provides = (
+            provide(int, provides=int)
+            + alias(source=int, provides=float)
+            + alias(source=int, provides=float)
+        )
+
+    make_container(
+        TestProvider(),
+        validation_settings=ValidationSettings(implicit_override=False),
+    )
+
+
+def test_override_ok() -> None:
+    class TestProvider(Provider):
+        scope = Scope.APP
+        provides = (
+            provide(int, provides=int)
+            + alias(source=int, provides=float)
+            + alias(source=int, provides=float, override=True)
+        )
+
+    make_container(
+        TestProvider(),
+        validation_settings=STRICT_VALIDATION,
+    )
+
+
+def test_cant_override() -> None:
+    class TestProvider(Provider):
+        scope = Scope.APP
+        provides = (
+            provide(int, provides=int)
+            + alias(source=int, provides=float, override=True)
+        )
+
+    with pytest.raises(NothingOverriddenError) as e:
+        make_container(
+            TestProvider(),
+            validation_settings=STRICT_VALIDATION,
+        )
+    assert str(e.value)
+
+
+def test_skip_cant_override() -> None:
+    class TestProvider(Provider):
+        scope = Scope.APP
+        provides = (
+            provide(int, provides=int)
+            + alias(source=int, provides=float, override=True)
+        )
+
+    make_container(
+        TestProvider(),
+        validation_settings=ValidationSettings(nothing_overridden=False),
+    )