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Feature | Ignore enhanced routing tokens when feature disabled by server #3971

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24 changes: 23 additions & 1 deletion ...Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/Connection/SqlConnectionInternal.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -1308,7 +1308,7 @@ internal void OnError(SqlException exception, bool breakConnection, Action<Actio
// @TODO: This class should not do low-level parsing of data from the server.
internal void OnFeatureExtAck(int featureId, byte[] data)
{
if (RoutingInfo != null && featureId != TdsEnums.FEATUREEXT_SQLDNSCACHING)
if (RoutingInfo != null && featureId != TdsEnums.FEATUREEXT_SQLDNSCACHING && featureId != TdsEnums.FEATUREEXT_ENHANCEDROUTINGSUPPORT)
{
return;
}
Expand Down Expand Up @@ -3288,6 +3288,17 @@ private void LoginNoFailover(

if (RoutingInfo != null)
{
// Check if we received enhanced routing info, but not the ack for the feature.
// In this case, we should ignore the routing info and connect to the current server.
if (!string.IsNullOrEmpty(RoutingInfo.DatabaseName) && !IsEnhancedRoutingSupportEnabled)
{
SqlClientEventSource.Log.TryTraceEvent(
$"SqlInternalConnectionTds.LoginNoFailover | " +
$"Ignoring enhanced routing info because the server did not acknowledge the feature.");
RoutingInfo = null;
break;
}
Comment on lines +3291 to +3300
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Copilot AI Feb 20, 2026

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IsEnhancedRoutingSupportEnabled is never reset between login attempts. In a multi-hop redirect scenario, the flag could remain true from a previous server that acknowledged enhanced routing, causing the client to incorrectly honor enhanced routing info from a subsequent server that did not acknowledge (or disabled) the feature. Consider resetting IsEnhancedRoutingSupportEnabled (and any related per-server feature-negotiation state) at the start of each AttemptOneLogin / login attempt so the decision to honor enhanced routing tokens is based only on the current server’s ACK.

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SqlClientEventSource.Log.TryTraceEvent(
$"SqlInternalConnectionTds.LoginNoFailover | " +
$"Routed to {serverInfo.ExtendedServerName}");
Expand Down Expand Up @@ -3589,6 +3600,17 @@ private void LoginWithFailover(
int routingAttempts = 0;
while (RoutingInfo != null)
{
// Check if we received enhanced routing info, but not the ack for the feature.
// In this case, we should ignore the routing info and connect to the current server.
if (!string.IsNullOrEmpty(RoutingInfo.DatabaseName) && !IsEnhancedRoutingSupportEnabled)
{
SqlClientEventSource.Log.TryTraceEvent(
$"SqlInternalConnectionTds.LoginWithFailover | " +
$"Ignoring enhanced routing info because the server did not acknowledge the feature.");
RoutingInfo = null;
continue;
}
Comment on lines +3603 to +3612
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Copilot AI Feb 20, 2026

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Same issue as in LoginNoFailover: because IsEnhancedRoutingSupportEnabled is not reset per login attempt, it can carry over across redirect hops and cause enhanced routing tokens to be honored even when the current server didn’t acknowledge/enable the feature. Reset the flag at the start of each login attempt (e.g., in AttemptOneLogin) so routing decisions reflect only the current server’s negotiation result.

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if (routingAttempts > MaxNumberOfRedirectRoute)
{
throw SQL.ROR_RecursiveRoutingNotSupported(this, MaxNumberOfRedirectRoute);
Expand Down
218 changes: 72 additions & 146 deletions ...oft.Data.SqlClient/tests/UnitTests/SimulatedServerTests/ConnectionEnhancedRoutingTests.cs
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Expand Up @@ -17,185 +17,111 @@ namespace Microsoft.Data.SqlClient.UnitTests.SimulatedServerTests;
[Collection("SimulatedServerTests")]
public class ConnectionEnhancedRoutingTests
{
[Fact]
public void RoutedConnection()
/// <summary>
/// Tests that a connection is routed to the target server when enhanced routing is enabled.
/// Uses Theory to test both sync and async code paths.
/// </summary>
[Theory]
[InlineData(false)]
[InlineData(true)]
public async Task RoutedConnection(bool useAsync)
{
// Arrange
using TdsServer server = new(new());
server.Start();
using TestRoutingServers servers = new(FeatureExtensionBehavior.Enabled);

string routingDatabaseName = Guid.NewGuid().ToString();
bool clientProvidedCorrectDatabase = false;
server.OnLogin7Validated = loginToken =>
servers.TargetServer.OnLogin7Validated = loginToken =>
{
clientProvidedCorrectDatabase = routingDatabaseName == loginToken.Database;
clientProvidedCorrectDatabase = servers.RoutingDatabaseName == loginToken.Database;
};

RoutingTdsServer router = new(
new RoutingTdsServerArguments()
{
RoutingTCPHost = "localhost",
RoutingTCPPort = (ushort)server.EndPoint.Port,
RoutingDatabaseName = routingDatabaseName,
RequireReadOnly = false
});
router.Start();
router.EnhancedRoutingBehavior = FeatureExtensionBehavior.Enabled;

string connectionString = (new SqlConnectionStringBuilder()
{
DataSource = $"localhost,{router.EndPoint.Port}",
Encrypt = false,
ConnectTimeout = 10000
}).ConnectionString;

// Act
using SqlConnection connection = new(connectionString);
connection.Open();

// Assert
Assert.Equal(ConnectionState.Open, connection.State);
Assert.Equal($"localhost,{server.EndPoint.Port}", ((SqlConnectionInternal)connection.InnerConnection).RoutingDestination);
Assert.Equal(routingDatabaseName, connection.Database);
Assert.True(clientProvidedCorrectDatabase);

Assert.Equal(1, router.PreLoginCount);
Assert.Equal(1, server.PreLoginCount);
}

[Fact]
public async Task RoutedAsyncConnection()
{
// Arrange
using TdsServer server = new(new());
server.Start();

string routingDatabaseName = Guid.NewGuid().ToString();
bool clientProvidedCorrectDatabase = false;
server.OnLogin7Validated = loginToken =>
using SqlConnection connection = new(servers.ConnectionString);
if (useAsync)
{
clientProvidedCorrectDatabase = routingDatabaseName == loginToken.Database;
};

RoutingTdsServer router = new(
new RoutingTdsServerArguments()
{
RoutingTCPHost = "localhost",
RoutingTCPPort = (ushort)server.EndPoint.Port,
RoutingDatabaseName = routingDatabaseName,
RequireReadOnly = false
});
router.Start();
router.EnhancedRoutingBehavior = FeatureExtensionBehavior.Enabled;

string connectionString = (new SqlConnectionStringBuilder()
await connection.OpenAsync();
}
else
{
DataSource = $"localhost,{router.EndPoint.Port}",
Encrypt = false,
ConnectTimeout = 10000
}).ConnectionString;

// Act
using SqlConnection connection = new(connectionString);
await connection.OpenAsync();
connection.Open();
}

// Assert
Assert.Equal(ConnectionState.Open, connection.State);
Assert.Equal($"localhost,{server.EndPoint.Port}", ((SqlConnectionInternal)connection.InnerConnection).RoutingDestination);
Assert.Equal(routingDatabaseName, connection.Database);
Assert.Equal($"localhost,{servers.TargetServer.EndPoint.Port}", ((SqlConnectionInternal)connection.InnerConnection).RoutingDestination);
Assert.Equal(servers.RoutingDatabaseName, connection.Database);
Assert.True(clientProvidedCorrectDatabase);

Assert.Equal(1, router.PreLoginCount);
Assert.Equal(1, server.PreLoginCount);
Assert.Equal(1, servers.Router.PreLoginCount);
Assert.Equal(1, servers.TargetServer.PreLoginCount);
}

[Fact]
public void ServerIgnoresEnhancedRoutingRequest()
/// <summary>
/// Tests that a connection is NOT routed when the server does not acknowledge the enhanced routing feature
/// or has it disabled. Covers both DoNotAcknowledge and Disabled behaviors.
/// </summary>
[Theory]
[InlineData(FeatureExtensionBehavior.DoNotAcknowledge)]
[InlineData(FeatureExtensionBehavior.Disabled)]
public void ServerDoesNotRoute(FeatureExtensionBehavior behavior)
{
// Arrange
using TdsServer server = new(new());
server.Start();

string routingDatabaseName = Guid.NewGuid().ToString();
bool clientProvidedCorrectDatabase = false;
server.OnLogin7Validated = loginToken =>
{
clientProvidedCorrectDatabase = null == loginToken.Database;
};

RoutingTdsServer router = new(
new RoutingTdsServerArguments()
{
RoutingTCPHost = "localhost",
RoutingTCPPort = (ushort)server.EndPoint.Port,
RequireReadOnly = false
});
router.Start();
router.EnhancedRoutingBehavior = FeatureExtensionBehavior.DoNotAcknowledge;

string connectionString = (new SqlConnectionStringBuilder()
{
DataSource = $"localhost,{router.EndPoint.Port}",
Encrypt = false,
ConnectTimeout = 10000
}).ConnectionString;
using TestRoutingServers servers = new(behavior);

// Act
using SqlConnection connection = new(connectionString);
using SqlConnection connection = new(servers.ConnectionString);
connection.Open();

Comment on lines +63 to 74
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Copilot AI Feb 20, 2026

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ServerDoesNotRoute only exercises the synchronous Open() path. Since the product change affects connection establishment/routing logic, add coverage for OpenAsync() as well (e.g., include a useAsync parameter like RoutedConnection) to ensure behavior matches in both sync and async code paths.

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// Assert
Assert.Equal(ConnectionState.Open, connection.State);
Assert.Equal($"localhost,{server.EndPoint.Port}", ((SqlConnectionInternal)connection.InnerConnection).RoutingDestination);
Assert.Null(((SqlConnectionInternal)connection.InnerConnection).RoutingDestination);
Assert.Equal("master", connection.Database);
Assert.True(clientProvidedCorrectDatabase);

Assert.Equal(1, router.PreLoginCount);
Assert.Equal(1, server.PreLoginCount);
Assert.Equal(1, servers.Router.PreLoginCount);
Assert.Equal(0, servers.TargetServer.PreLoginCount);
}

[Fact]
public void ServerRejectsEnhancedRoutingRequest()
/// <summary>
/// Helper class that encapsulates the setup of a routing TDS server and target TDS server
/// for enhanced routing tests.
/// </summary>
private sealed class TestRoutingServers : IDisposable
{
// Arrange
using TdsServer server = new(new());
server.Start();
public TdsServer TargetServer { get; }
public RoutingTdsServer Router { get; }
public string RoutingDatabaseName { get; }
public string ConnectionString { get; }

string routingDatabaseName = Guid.NewGuid().ToString();
bool clientProvidedCorrectDatabase = false;
server.OnLogin7Validated = loginToken =>
public TestRoutingServers(FeatureExtensionBehavior enhancedRoutingBehavior)
{
clientProvidedCorrectDatabase = null == loginToken.Database;
};

RoutingTdsServer router = new(
new RoutingTdsServerArguments()
RoutingDatabaseName = Guid.NewGuid().ToString();

TargetServer = new TdsServer(new());
TargetServer.Start();

Router = new RoutingTdsServer(
new RoutingTdsServerArguments()
{
RoutingTCPHost = "localhost",
RoutingTCPPort = (ushort)TargetServer.EndPoint.Port,
RoutingDatabaseName = RoutingDatabaseName,
RequireReadOnly = false
});
Router.Start();
Router.EnhancedRoutingBehavior = enhancedRoutingBehavior;

ConnectionString = new SqlConnectionStringBuilder()
{
RoutingTCPHost = "localhost",
RoutingTCPPort = (ushort)server.EndPoint.Port,
RequireReadOnly = false
});
router.Start();
router.EnhancedRoutingBehavior = FeatureExtensionBehavior.Disabled;

string connectionString = (new SqlConnectionStringBuilder()
{
DataSource = $"localhost,{router.EndPoint.Port}",
Encrypt = false,
ConnectTimeout = 10000
}).ConnectionString;

// Act
using SqlConnection connection = new(connectionString);
connection.Open();

// Assert
Assert.Equal(ConnectionState.Open, connection.State);
Assert.Equal($"localhost,{server.EndPoint.Port}", ((SqlConnectionInternal)connection.InnerConnection).RoutingDestination);
Assert.Equal("master", connection.Database);
Assert.True(clientProvidedCorrectDatabase);
DataSource = $"localhost,{Router.EndPoint.Port}",
Encrypt = false,
ConnectTimeout = 10000
}.ConnectionString;
}

Assert.Equal(1, router.PreLoginCount);
Assert.Equal(1, server.PreLoginCount);
public void Dispose()
{
Router?.Dispose();
TargetServer?.Dispose();
}
}
}
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