Вы можете создавать зависимости, которые имеют **подзависимости**.

Их **вложенность** может быть любой глубины.

**FastAPI** сам займётся их управлением.

## Первая зависимость { #first-dependency-dependable }

Можно создать первую зависимость следующим образом:

{* ../../docs_src/dependencies/tutorial005_an_py310.py hl[8:9] *}

Она объявляет необязательный параметр запроса `q` как строку, а затем возвращает его.

    <version>0.2</version>
    <packaging>pom</packaging>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.junit</groupId>
                <artifactId>junit</artifactId>
                <version>0.2</version>
            </dependency>
        </dependencies>
    </dependencyManagement>

  <packaging>pom</packaging>
  <name>p1</name>
  <version>1.0</version>
  <scm>
    <url>scm-url</url>
  </scm>

  <dependencies>

    <dependency>
      <groupId>maven-test</groupId>
      <artifactId>t09-a</artifactId>
    </dependency>

  </dependencies>

  <build>
    <plugins>
      <plugin>
        <artifactId>maven-antrun-plugin</artifactId>
        <configuration>

            if (data instanceof DependencyRequest request) {
                return "dependency resolution for " + request;
            } else if (data instanceof CollectRequest request) {
                return "dependency collection for " + request;
            } else if (data instanceof CollectStepData stepData) {
                String msg = "dependency collection step for " + stepData.getContext();
                if (detailed) {

    /**
     * Sets the filter used to exclude some dependencies from resolution. Note that this filter only controls the
     * resolution/download of dependency artifacts, not the inclusion of dependency nodes in the resolved dependency
     * graph.
     *
     * @param filter The filter to exclude dependencies from resolution, may be {@code null} to resolve all
     *            dependencies.

    <version>0.1-SNAPSHOT</version>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.junit</groupId>
                <artifactId>bom</artifactId>
                <version>0.1</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

        this.plugin = plugin;
        setFile(pluginArtifact.getFile());
        setResolved(true);
    }

    @Override
    public List<Dependency> getDependencies() {
        return plugin.getDependencies();
    }

    @Override
    public List<Dependency> getManagedDependencies() {
        return Collections.emptyList();
    }

    // TODO: this is duplicate of MavenPluginArtifactHandlerProvider provided one

    }
)

client = TestClient(app)


def raise_value_error():
    raise ValueError()


def dependency_with_yield():
    yield raise_value_error()


@app.get("/dependency-with-yield", dependencies=[Depends(dependency_with_yield)])
def with_yield(): ...


@app.get("/http-exception")
def route_with_http_exception():
    raise HTTPException(status_code=400)

    <name>Maven Integration Test :: Dummy BOM</name>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.apache.maven.its</groupId>
                <artifactId>a</artifactId>
                <version>0.1</version>
            </dependency>
        </dependencies>
    </dependencyManagement>

    assert callable(depends.dependency), (
        "A parameter-less dependency must have a callable dependency"
    )
    own_oauth_scopes: list[str] = []
    if isinstance(depends, params.Security) and depends.scopes:
        own_oauth_scopes.extend(depends.scopes)
    return get_dependant(
        path=path,
        call=depends.dependency,
        scope=depends.scope,