## Injeção de dependências { #dependency-injection }

Usar `BackgroundTasks` também funciona com o sistema de injeção de dependências; você pode declarar um parâmetro do tipo `BackgroundTasks` em vários níveis: em uma *função de operação de rota*, em uma dependência (dependable), em uma subdependência, etc.

    assert global_state["session_closed"] is True
    assert global_state["named_session_closed"] is True


def test_broken_scope() -> None:
    with pytest.raises(
        FastAPIError,
        match='The dependency "get_named_func_session" has a scope of "request", it cannot depend on dependencies with scope "function"',
    ):

        @app.websocket("/broken-scope")
        async def get_broken(

      throw AssertionError("failed to get ALPN selected protocol", e)
    }
  }

  /**
   * Handle the methods of ALPN's ClientProvider and ServerProvider without a compile-time
   * dependency on those interfaces.
   */
  private class AlpnProvider(
    /** This peer's supported protocols. */
    private val protocols: List<String>,
  ) : InvocationHandler {

import static org.eclipse.aether.impl.scope.BuildScopeQuery.union;

/**
 * Maven3 scope configurations. Configures scope manager to support Maven3 scopes.
 * <p>
 * This manager supports the old Maven 3 dependency scopes.
 *
 * @since 2.0.0
 * @deprecated since 4.0.0, use {@code maven-api-impl} jar instead
 */
@Deprecated(since = "4.0.0")
public final class Maven3ScopeManagerConfiguration implements ScopeManagerConfiguration {

 * {{{./lifecycles.html}lifecycles}} and {{{./default-bindings.html}plugin bindings to <<<default>>> lifecycle}},

 * {{{./artifact-handlers.html}default artifact handlers}}, to manage {{{../maven-model/maven.html#class_dependency}dependency types}},

 * {{{./extension.html}extension descriptor}} and {{{./core-extensions.html}core extensions}},

 * {{{/guides/mini/guide-maven-classloading.html}classloader hierarchy}} done by <<<ClassRealmManager>>> component

Podemos hacerlo mejor...

## Qué hace a una dependencia { #what-makes-a-dependency }

Hasta ahora has visto dependencias declaradas como funciones.

Pero esa no es la única forma de declarar dependencias (aunque probablemente sea la más común).

El factor clave es que una dependencia debe ser un "callable".

        assertNotNull(dep, "No dependencyManagement");
        List<?> list = dep.getDependencies();
        assertNotNull(list, "No dependencies");
        assertTrue(!list.isEmpty(), "Empty dependency list");

        Map<?, ?> map = projectToClone.getManagedVersionMap();
        assertNotNull(map, "No ManagedVersionMap");
        assertTrue(!map.isEmpty(), "ManagedVersionMap is empty");

            return resolved;
        }

        /*

        Logic for transitive global exclusions

        List<String> exclusions = new ArrayList<String>();

        for ( Dependency d : project.getDependencies() )
        {
            if ( d.getExclusions() != null )
            {
                for ( Exclusion e : d.getExclusions() )
                {

        }

        return Collections.unmodifiableList(errorArtifactExceptions);
    }

    // ------------------------------------------------------------------------
    // Circular Dependency Exceptions
    // ------------------------------------------------------------------------

    public boolean hasCircularDependencyExceptions() {
        return circularDependencyExceptions != null;
    }

            logger.warn("\n\tArtifact " + artifact + " retains local artifactScope '" + artifact.getScope()
                    + "' overriding broader artifactScope '" + ignoredScope + "'\n"
                    + "\tgiven by a dependency. If this is not intended, modify or remove the local artifactScope.\n");
            ignoredArtifacts.add(artifact);
        }
    }

    @Override
    public void updateScope(Artifact artifact, String scope) {