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

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

                Throwable cause = exception.getCause();

from fastapi import Depends, FastAPI, HTTPException
from fastapi.exceptions import RequestValidationError
from fastapi.testclient import TestClient
from starlette.responses import JSONResponse


def http_exception_handler(request, exception):
    return JSONResponse({"exception": "http-exception"})


def request_validation_exception_handler(request, exception):
    return JSONResponse({"exception": "request-validation"})

{* ../../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] *}

# Exceptions - `HTTPException` and `WebSocketException`

These are the exceptions that you can raise to show errors to the client.

When you raise an exception, as would happen with normal Python, the rest of the execution is aborted. This way you can raise these exceptions from anywhere in the code to abort a request and show the error to the client.

You can use:

* `HTTPException`
* `WebSocketException`

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;