String reference = "";
        if (!dejaVu.add(exception)) {
            return reference;
        }

        if (exception != null) {
            if (exception instanceof MojoExecutionException) {
                reference = MojoExecutionException.class.getSimpleName();

                Throwable cause = exception.getCause();

{* ../../docs_src/handling_errors/tutorial002_py39.py hl[14] *}

## Install custom exception handlers { #install-custom-exception-handlers }

You can add custom exception handlers with <a href="https://www.starlette.dev/exceptions/" class="external-link" target="_blank">the same exception utilities from Starlette</a>.

Let's say you have a custom exception `UnicornException` that you (or a library you use) might `raise`.

    captured_exception.exception = None
    try:
        client.get("/items/")
    except Exception:
        pass

    assert captured_exception.exception is not None
    error_str = str(captured_exception.exception)
    assert "get_item" in error_str
    assert "/items/" in error_str


def test_websocket_validation_error_includes_endpoint_context():
    captured_exception.exception = None
    try:

Wenn Sie eine Exception in einer Abhängigkeit mit `yield` abfangen, sollten Sie – sofern Sie nicht eine andere `HTTPException` oder Ähnliches auslösen – **die ursprüngliche Exception erneut auslösen**.

Sie können dieselbe Exception mit `raise` erneut auslösen:

{* ../../docs_src/dependencies/tutorial008d_an_py39.py hl[17] *}

If you use a `try` block in a dependency with `yield`, you'll receive any exception that was thrown when using the dependency.

For example, if some code at some point in the middle, in another dependency or in a *path operation*, made a database transaction "rollback" or created any other exception, you would receive the exception in your dependency.

So, you can look for that specific exception inside the dependency with `except SomeException`.

from pydantic import BaseModel, create_model
from starlette.exceptions import HTTPException as StarletteHTTPException
from starlette.exceptions import WebSocketException as StarletteWebSocketException


class EndpointContext(TypedDict, total=False):
    function: str
    path: str
    file: str
    line: int


class HTTPException(StarletteHTTPException):
    """
    An HTTP exception you can raise in your own code to show errors to the client.

    }

    @Test
    void testDuplicatePluginExecution() throws Exception {
        SimpleProblemCollector result = validateRaw("duplicate-plugin-execution.xml");

        assertViolations(result, 0, 4, 0);

        assertContains(result.getErrors().get(0), "duplicate execution with id a");
        assertContains(result.getErrors().get(1), "duplicate execution with id default");

import org.apache.maven.configuration.internal.EnhancedComponentConfigurator;
import org.apache.maven.execution.DefaultMavenExecutionRequest;
import org.apache.maven.execution.DefaultMavenExecutionResult;
import org.apache.maven.execution.MavenExecutionRequest;
import org.apache.maven.execution.MavenSession;
import org.apache.maven.impl.model.reflection.IntrospectionException;
import org.apache.maven.model.Build;

    protected void createLocalArtifact(Artifact artifact) throws Exception {
        createArtifact(artifact, localRepository());
    }

    protected void createRemoteArtifact(Artifact artifact) throws Exception {
        createArtifact(artifact, remoteRepository());
    }

    protected void createArtifact(Artifact artifact, ArtifactRepository repository) throws Exception {
        String path = repository.pathOf(artifact);

import org.apache.maven.configuration.internal.EnhancedComponentConfigurator;
import org.apache.maven.execution.DefaultMavenExecutionRequest;
import org.apache.maven.execution.DefaultMavenExecutionResult;
import org.apache.maven.execution.MavenExecutionRequest;
import org.apache.maven.execution.MavenSession;
import org.apache.maven.impl.model.reflection.IntrospectionException;
import org.apache.maven.internal.impl.DefaultLookup;