Fix NRE when using bad authentication and ping is enabled.

src/Elastic.Transport/Components/Pipeline/DefaultRequestPipeline.cs

@@ -35,7 +35,7 @@ public class DefaultRequestPipeline<TConfiguration> : RequestPipeline
 
 	private static readonly ActivitySource _activitySource = new("Elastic.Transport.RequestPipeline");
 
-	private RequestConfiguration _pingAndSniffRequestConfiguration;
+	private RequestConfiguration? _pingAndSniffRequestConfiguration;
 	private List<Audit> _auditTrail = null;
 
 	/// <inheritdoc cref="RequestPipeline" />
@@ -73,7 +73,7 @@ private RequestConfiguration PingAndSniffRequestConfiguration
 			{
 				PingTimeout = PingTimeout,
 				RequestTimeout = PingTimeout,
-				AuthenticationHeader = _settings.Authentication,
+				AuthenticationHeader = RequestConfiguration?.AuthenticationHeader ?? _settings.Authentication,
 				EnableHttpPipelining = RequestConfiguration?.EnableHttpPipelining ?? _settings.HttpPipeliningEnabled,
 				ForceNode = RequestConfiguration?.ForceNode
 			};
@@ -277,14 +277,14 @@ public override async Task<TResponse> CallProductEndpointAsync<TResponse>(Reques
 		}
 	}
 
-	public override TransportException CreateClientException<TResponse>(
-		TResponse response, ApiCallDetails callDetails, RequestData data, List<PipelineException> pipelineExceptions)
+	public override TransportException? CreateClientException<TResponse>(TResponse response, ApiCallDetails? callDetails,
+		RequestData data, List<PipelineException> seenExceptions)
 	{
 		if (callDetails?.HasSuccessfulStatusCodeAndExpectedContentType ?? false) return null;
 
 		var pipelineFailure = data.OnFailurePipelineFailure;
 		var innerException = callDetails?.OriginalException;
-		if (pipelineExceptions.HasAny(out var exs))
+		if (seenExceptions.HasAny(out var exs))
 		{
 			pipelineFailure = exs.Last().FailureReason;
 			innerException = exs.AsAggregateOrFirst();

src/Elastic.Transport/Components/Pipeline/PipelineException.cs

@@ -35,7 +35,7 @@ public PipelineException(PipelineFailure failure, Exception innerException)
 		|| FailureReason == PipelineFailure.PingFailure;
 
 	/// <summary> The response that triggered this exception </summary>
-	public TransportResponse Response { get; internal set; }
+	public TransportResponse? Response { get; internal set; }
 
 	private static string GetMessage(PipelineFailure failure) =>
 		failure switch

src/Elastic.Transport/Components/Pipeline/RequestData.cs

@@ -140,7 +140,7 @@ MemoryStreamFactory memoryStreamFactory
 	public MemoryStreamFactory MemoryStreamFactory { get; }
 	public HttpMethod Method { get; }
 
-	public Node Node
+	public Node? Node
 	{
 		get => _node;
 		set
@@ -240,7 +240,7 @@ internal bool ValidateResponseContentType(string responseMimeType)
 			// - 404 responses from ES8 don't include the vendored header
 			// - ES8 EQL responses don't include vendored type
 
-			|| trimmedAccept.Contains("application/vnd.elasticsearch+json") && trimmedResponseMimeType.StartsWith(DefaultMimeType, StringComparison.OrdinalIgnoreCase); 
+			|| trimmedAccept.Contains("application/vnd.elasticsearch+json") && trimmedResponseMimeType.StartsWith(DefaultMimeType, StringComparison.OrdinalIgnoreCase);
 	}
 
 	public static string ToQueryString(NameValueCollection collection) => collection.ToQueryString();

src/Elastic.Transport/Components/Pipeline/RequestPipeline.cs

@@ -94,13 +94,13 @@ public abstract void BadResponse<TResponse>(ref TResponse response, ApiCallDetai
 
 	public abstract void AuditCancellationRequested();
 
-	public abstract TransportException CreateClientException<TResponse>(TResponse response, ApiCallDetails callDetails, RequestData data,
-		List<PipelineException> seenExceptions)
+	public abstract TransportException? CreateClientException<TResponse>(TResponse? response, ApiCallDetails? callDetails,
+		RequestData data, List<PipelineException> seenExceptions)
 		where TResponse : TransportResponse, new();
 #pragma warning restore 1591
 
 	/// <summary>
-	/// 
+	///
 	/// </summary>
 	public void Dispose()
 	{
@@ -109,7 +109,7 @@ public void Dispose()
 	}
 
 	/// <summary>
-	/// 
+	///
 	/// </summary>
 	/// <param name="disposing"></param>
 	protected virtual void Dispose(bool disposing)
@@ -126,7 +126,7 @@ protected virtual void Dispose(bool disposing)
 	}
 
 	/// <summary>
-	/// 
+	///
 	/// </summary>
 	protected virtual void DisposeManagedResources() { }
 }

src/Elastic.Transport/DefaultHttpTransport.cs

@@ -126,21 +126,20 @@ public DefaultHttpTransport(
 	private RequestPipelineFactory<TConfiguration> PipelineProvider { get; }
 
 	/// <summary>
-	/// 
+	///
 	/// </summary>
 	public override TConfiguration Settings { get; }
 
 	/// <summary>
-	/// 
+	///
 	/// </summary>
 	/// <typeparam name="TResponse"></typeparam>
 	/// <param name="method"></param>
 	/// <param name="path"></param>
 	/// <param name="data"></param>
 	/// <param name="requestParameters"></param>
 	/// <returns></returns>
-	public override TResponse Request<TResponse>(HttpMethod method, string path, PostData data = null,
-		RequestParameters requestParameters = null)
+	public override TResponse Request<TResponse>(HttpMethod method, string path, PostData? data = null, RequestParameters? requestParameters = null)
 	{
 		using var pipeline =
 			PipelineProvider.Create(Settings, DateTimeProvider, MemoryStreamFactory, requestParameters);
@@ -217,7 +216,7 @@ public override TResponse Request<TResponse>(HttpMethod method, string path, Pos
 	}
 
 	/// <summary>
-	/// 
+	///
 	/// </summary>
 	/// <typeparam name="TResponse"></typeparam>
 	/// <param name="method"></param>
@@ -228,7 +227,7 @@ public override TResponse Request<TResponse>(HttpMethod method, string path, Pos
 	/// <returns></returns>
 	/// <exception cref="UnexpectedTransportException"></exception>
 	public override async Task<TResponse> RequestAsync<TResponse>(HttpMethod method, string path,
-		PostData data = null, RequestParameters requestParameters = null,
+		PostData? data = null, RequestParameters? requestParameters = null,
 		CancellationToken cancellationToken = default)
 	{
 		using var pipeline =
@@ -343,7 +342,7 @@ ICollection<PipelineException> seenExceptions
 
 	private TResponse FinalizeResponse<TResponse>(RequestData requestData, RequestPipeline pipeline,
 		List<PipelineException> seenExceptions,
-		TResponse response
+		TResponse? response
 	) where TResponse : TransportResponse, new()
 	{
 		if (requestData.Node == null) //foreach never ran
@@ -359,11 +358,11 @@ TResponse response
 		return response;
 	}
 
-	private static ApiCallDetails GetMostRecentCallDetails<TResponse>(TResponse response,
+	private static ApiCallDetails? GetMostRecentCallDetails<TResponse>(TResponse? response,
 		IEnumerable<PipelineException> seenExceptions)
 		where TResponse : TransportResponse, new()
 	{
-		var callDetails = response?.ApiCallDetails ?? seenExceptions.LastOrDefault(e => e.Response.ApiCallDetails != null)?.Response.ApiCallDetails;
+		var callDetails = response?.ApiCallDetails ?? seenExceptions.LastOrDefault(e => e.Response?.ApiCallDetails != null)?.Response?.ApiCallDetails;
 		return callDetails;
 	}
 

src/Elastic.Transport/HttpTransport.cs

@@ -18,16 +18,16 @@ public abstract class HttpTransport
 	public abstract TResponse Request<TResponse>(
 		HttpMethod method,
 		string path,
-		PostData data = null,
-		RequestParameters requestParameters = null)
+		PostData? data = null,
+		RequestParameters? requestParameters = null)
 		where TResponse : TransportResponse, new();
 
 	/// <inheritdoc cref="Request{TResponse}" />
 	public abstract Task<TResponse> RequestAsync<TResponse>(
 		HttpMethod method,
 		string path,
-		PostData data = null,
-		RequestParameters requestParameters = null,
+		PostData? data = null,
+		RequestParameters? requestParameters = null,
 		CancellationToken cancellationToken = default)
 		where TResponse : TransportResponse, new();
 }

tests/Elastic.Elasticsearch.IntegrationTests/DefaultCluster.cs

@@ -5,6 +5,7 @@
 using Elastic.Elasticsearch.Ephemeral;
 using Elastic.Elasticsearch.Xunit;
 using Elastic.Transport;
+using Elastic.Transport.Products.Elasticsearch;
 using Xunit;
 using Xunit.Abstractions;
 using static Elastic.Elasticsearch.Ephemeral.ClusterAuthentication;
@@ -28,7 +29,7 @@ public DefaultHttpTransport CreateClient(ITestOutputHelper output) =>
 				: "localhost");
 			var nodes = NodesUris(hostName);
 			var connectionPool = new StaticNodePool(nodes);
-			var settings = new TransportConfiguration(connectionPool)
+			var settings = new TransportConfiguration(connectionPool, productRegistration: ElasticsearchProductRegistration.Default)
 				.Proxy(new Uri("http://ipv4.fiddler:8080"), null!, null!)
 				.RequestTimeout(TimeSpan.FromSeconds(5))
 				.ServerCertificateValidationCallback(CertificateValidations.AllowAll)

tests/Elastic.Elasticsearch.IntegrationTests/SecurityClusterTests.cs

@@ -29,4 +29,18 @@ public void SyncRequestDoesNotThrow()
 		response.ApiCallDetails.Should().NotBeNull();
 		response.ApiCallDetails.HasSuccessfulStatusCode.Should().BeTrue();
 	}
+
+	[Fact]
+	public void SyncRequestDoesNotThrowOnBadAuth()
+	{
+		var response = Transport.Request<StringResponse>(GET, "/", null, new DefaultRequestParameters
+		{
+			RequestConfiguration = new RequestConfiguration
+			{
+				AuthenticationHeader = new BasicAuthentication("unknown-user", "bad-password")
+			}
+		});
+		response.ApiCallDetails.Should().NotBeNull();
+		response.ApiCallDetails.HasSuccessfulStatusCode.Should().BeFalse();
+	}
 }