我們身為人，常常會犯錯。軟體幾乎總是有藏在各處的「臭蟲（bugs）」🐛

而我們開發者會在發現這些 bug 後持續改進程式碼、實作新功能（也可能順便加進新的 bug 😅）。

### 小錯誤自動處理 { #small-errors-automatically-handled }

使用 FastAPI 建構 Web API 時，如果我們的程式碼出錯，FastAPI 通常會把它限制在觸發該錯誤的單次請求之中。🛡

用戶端會收到「500 Internal Server Error」，但應用會繼續處理之後的請求，而不是整個崩潰。

### 更嚴重的錯誤 - 當機 { #bigger-errors-crashes }

然而，仍可能有一些情況，我們寫的程式碼「讓整個應用當機」，使 Uvicorn 與 Python 都崩潰。💥

 * <ul>
 *   <li>missing metadata</li>
 *   <li>version range violations</li>
 *   <li>version circular dependencies</li>
 *   <li>missing artifacts</li>
 *   <li>network/transfer errors</li>
 *   <li>file system errors: permissions</li>
 * </ul>
 *
 * TODO carlos: all these possible has*Exceptions and get*Exceptions methods make the clients too

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.codelibs.fess.Constants;
import org.codelibs.fess.app.web.base.FessSearchAction;
import org.codelibs.fess.app.web.error.ErrorAction;
import org.codelibs.fess.util.DocumentUtil;
import org.lastaflute.web.Execute;
import org.lastaflute.web.response.ActionResponse;
import org.lastaflute.web.response.StreamResponse;

/**

    listener.assertOpen()
    listener.assertFailure("canceled")
  }

  @Test
  fun failureWith401IsReadable() {
    server.enqueue(
      MockResponse(
        code = 401,
        body = "{\"error\":{\"message\":\"No auth credentials found\",\"code\":401}}",
        headers = Headers.headersOf("content-type", "application/json"),
      ),
    )
    server.enqueue(
      MockResponse(
        body =

     * @param invokerRequest the request containing all necessary information for the invocation
     * @return an integer representing the exit code of the invocation (0 typically indicates success)
     * @throws InvokerException if an error occurs during the invocation process.
     */
    int invoke(@Nonnull InvokerRequest invokerRequest) throws InvokerException;

    /**

                a = factory.createBuildArtifact("org.apache.maven", "h", "1.0", "jar");
                dependencies.add(a);
            } catch (Exception e) {
                throw new ArtifactMetadataRetrievalException("Error retrieving metadata", e, a);
            }
        }

        if ("i".equals(artifact.getArtifactId())) {
            Artifact a = null;
            try {

    client = TestClient(app, raise_server_exceptions=False)
    response = client.get("/broken-session-data")
    assert response.status_code == 500
    assert response.text == "Internal Server Error"


def test_broken_session_stream_raise():
    # Can raise ValueError on Pydantic v2 and ExceptionGroup on Pydantic v1
    with pytest.raises((ValueError, Exception)):
        client.get("/broken-session-stream")

                                "content": {"application/json": {"schema": {}}},
                            },
                            "422": {
                                "description": "Validation Error",
                                "content": {
                                    "application/json": {
                                        "schema": {

                                "content": {"application/json": {"schema": {}}},
                            },
                            "422": {
                                "description": "Validation Error",
                                "content": {
                                    "application/json": {
                                        "schema": {

# limitations under the License.
# ==============================================================================
if [[ "$TFCI_DOCKER_PULL_ENABLE" == 1 ]]; then
  # Simple retry logic for docker-pull errors. Sleeps if a pull fails.
  # Pulling an already-pulled container image will finish instantly, so
  # repeating the command costs nothing.
  docker pull "$TFCI_DOCKER_IMAGE" || sleep 15