Improve server identification handling and add integration tests

Co-authored-by: bgrainger <[email protected]>

Author: Copilot

src/MySqlConnector/Core/ServerSession.cs

@@ -2015,9 +2015,9 @@ private async Task GetServerIdentificationAsync(IOBehavior ioBehavior, Cancellat
 
 				var reader = new ByteArrayReader(payload.Span);
 				var length = reader.ReadLengthEncodedIntegerOrNull();
-				var serverUuid = length != -1 ? Encoding.UTF8.GetString(reader.ReadByteString(length)) : null;
+				var serverUuid = length > 0 ? Encoding.UTF8.GetString(reader.ReadByteString(length)) : null;
 				length = reader.ReadLengthEncodedIntegerOrNull();
-				var serverId = (length != -1 && Utf8Parser.TryParse(reader.ReadByteString(length), out long id, out _)) ? id : default(long?);
+				var serverId = (length > 0 && Utf8Parser.TryParse(reader.ReadByteString(length), out long id, out _)) ? id : default(long?);
 
 				ServerUuid = serverUuid;
 				ServerId = serverId;
@@ -2047,7 +2047,7 @@ private async Task GetServerIdentificationAsync(IOBehavior ioBehavior, Cancellat
 
 				var reader = new ByteArrayReader(payload.Span);
 				var length = reader.ReadLengthEncodedIntegerOrNull();
-				var serverId = (length != -1 && Utf8Parser.TryParse(reader.ReadByteString(length), out long id, out _)) ? id : default(long?);
+				var serverId = (length > 0 && Utf8Parser.TryParse(reader.ReadByteString(length), out long id, out _)) ? id : default(long?);
 
 				ServerUuid = null;
 				ServerId = serverId;
@@ -2065,6 +2065,9 @@ private async Task GetServerIdentificationAsync(IOBehavior ioBehavior, Cancellat
 		catch (MySqlException ex)
 		{
 			Log.FailedToGetServerIdentification(m_logger, ex, Id);
+			// Set fallback values to ensure operation can continue
+			ServerUuid = null;
+			ServerId = null;
 		}
 	}
 

tests/IntegrationTests/ServerIdentificationTests.cs

@@ -0,0 +1,73 @@
+using System.Diagnostics;
+
+namespace IntegrationTests;
+
+public class ServerIdentificationTests : IClassFixture<DatabaseFixture>, IDisposable
+{
+	public ServerIdentificationTests(DatabaseFixture database)
+	{
+		m_database = database;
+	}
+
+	public void Dispose()
+	{
+	}
+
+	[SkippableFact(ServerFeatures.Timeout)]
+	public void CancelCommand_WithServerVerification()
+	{
+		// This test verifies that cancellation still works with server verification
+		using var connection = new MySqlConnection(AppConfig.ConnectionString);
+		connection.Open();
+		
+		using var cmd = new MySqlCommand("SELECT SLEEP(5)", connection);
+		var task = Task.Run(async () =>
+		{
+			await Task.Delay(TimeSpan.FromSeconds(0.5));
+			cmd.Cancel();
+		});
+
+		var stopwatch = Stopwatch.StartNew();
+		TestUtilities.AssertExecuteScalarReturnsOneOrIsCanceled(cmd);
+		Assert.InRange(stopwatch.ElapsedMilliseconds, 250, 2500);
+
+#pragma warning disable xUnit1031 // Do not use blocking task operations in test method
+		task.Wait(); // shouldn't throw
+#pragma warning restore xUnit1031 // Do not use blocking task operations in test method
+
+		TestUtilities.LogInfo("Cancellation with server verification completed successfully");
+	}
+
+	[SkippableFact(ServerFeatures.KnownCertificateAuthority)]  
+	public void ServerHasServerIdentification()
+	{
+		using var connection = new MySqlConnection(AppConfig.ConnectionString);
+		connection.Open();
+
+		// Test that we can query server identification manually
+		using var cmd = new MySqlCommand("SELECT @@server_id", connection);
+		var serverId = cmd.ExecuteScalar();
+		Assert.NotNull(serverId);
+		TestUtilities.LogInfo($"Server ID: {serverId}");
+
+		// Test server UUID if available (MySQL 5.6+)
+		if (connection.ServerVersion.Version.Major > 5 || 
+			(connection.ServerVersion.Version.Major == 5 && connection.ServerVersion.Version.Minor >= 6))
+		{
+			try
+			{
+				using var uuidCmd = new MySqlCommand("SELECT @@server_uuid", connection);
+				var serverUuid = uuidCmd.ExecuteScalar();
+				Assert.NotNull(serverUuid);
+				TestUtilities.LogInfo($"Server UUID: {serverUuid}");
+			}
+			catch (MySqlException ex) when (ex.ErrorCode == MySqlErrorCode.UnknownSystemVariable)
+			{
+				// Some MySQL-compatible servers might not support server_uuid
+				TestUtilities.LogInfo("Server UUID not supported on this server");
+			}
+		}
+	}
+
+	private readonly DatabaseFixture m_database;
+}