CSHARP-3480: Switch to using maxWireVersion rather than buildInfo to determine feature support. (#720)

CSHARP-3480: Switch to using maxWireVersion rather than buildInfo to determine feature support.

Author: DmitryLukyanov

src/MongoDB.Driver.Core/Core/Authentication/DefaultAuthenticator.cs

@@ -84,16 +84,15 @@ public void Authenticate(IConnection connection, ConnectionDescription descripti
             // hello or legacy hello request and should query the server (provided that the server >= 4.0), merging results into
             // a new ConnectionDescription
             if (!description.HelloResult.HasSaslSupportedMechs
-                && Feature.ScramSha256Authentication.IsSupported(description.ServerVersion))
+                && Feature.ScramSha256Authentication.IsSupported(description.MaxWireVersion))
             {
                 var command = CustomizeInitialHelloCommand(HelloHelper.CreateCommand(_serverApi));
                 var helloProtocol = HelloHelper.CreateProtocol(command, _serverApi);
                 var helloResult = HelloHelper.GetResult(connection, helloProtocol, cancellationToken);
                 var mergedHelloResult = new HelloResult(description.HelloResult.Wrapped.Merge(helloResult.Wrapped));
                 description = new ConnectionDescription(
                     description.ConnectionId,
-                    mergedHelloResult,
-                    description.BuildInfoResult);
+                    mergedHelloResult);
             }
 
             var authenticator = GetOrCreateAuthenticator(connection, description);
@@ -110,16 +109,15 @@ public async Task AuthenticateAsync(IConnection connection, ConnectionDescriptio
             // hello or legacy hello request and should query the server (provided that the server >= 4.0), merging results into
             // a new ConnectionDescription
             if (!description.HelloResult.HasSaslSupportedMechs
-                && Feature.ScramSha256Authentication.IsSupported(description.ServerVersion))
+                && Feature.ScramSha256Authentication.IsSupported(description.MaxWireVersion))
             {
                 var command = CustomizeInitialHelloCommand(HelloHelper.CreateCommand(_serverApi));
                 var helloProtocol = HelloHelper.CreateProtocol(command, _serverApi);
                 var helloResult = await HelloHelper.GetResultAsync(connection, helloProtocol, cancellationToken).ConfigureAwait(false);
                 var mergedHelloResult = new HelloResult(description.HelloResult.Wrapped.Merge(helloResult.Wrapped));
                 description = new ConnectionDescription(
                     description.ConnectionId,
-                    mergedHelloResult,
-                    description.BuildInfoResult);
+                    mergedHelloResult);
             }
 
             var authenticator = GetOrCreateAuthenticator(connection, description);

src/MongoDB.Driver.Core/Core/Bindings/CoreSession.cs

@@ -510,13 +510,13 @@ private void EnsureTransactionsAreSupported()
                     case ServerType.Standalone:
                         throw new NotSupportedException("Standalone servers do not support transactions.");
                     case ServerType.ShardRouter:
-                        Feature.ShardedTransactions.ThrowIfNotSupported(connectedDataBearingServer.Version);
+                        Feature.ShardedTransactions.ThrowIfNotSupported(connectedDataBearingServer.MaxWireVersion);
                         break;
                     case ServerType.LoadBalanced:
                         // do nothing, load balancing always supports transactions
                         break;
                     default:
-                        Feature.Transactions.ThrowIfNotSupported(connectedDataBearingServer.Version);
+                        Feature.Transactions.ThrowIfNotSupported(connectedDataBearingServer.MaxWireVersion);
                         break;
                 }
             }

src/MongoDB.Driver.Core/Core/Clusters/Cluster.cs

@@ -38,9 +38,9 @@ internal abstract class Cluster : ICluster
         #region static
         // static fields
         private static readonly TimeSpan __minHeartbeatIntervalDefault = TimeSpan.FromMilliseconds(500);
-        private static readonly SemanticVersion __minSupportedServerVersion = new SemanticVersion(3, 6, 0);
+        private static readonly SemanticVersion __minSupportedServerVersion = WireVersion.ToServerVersion(WireVersion.SupportedWireVersionRange.Min);
         private static readonly IServerSelector __randomServerSelector = new RandomServerSelector();
-        private static readonly Range<int> __supportedWireVersionRange = new Range<int>(6, 15);
+        private static readonly Range<int> __supportedWireVersionRange = WireVersion.SupportedWireVersionRange;
 
         // static properties
         /// <summary>

src/MongoDB.Driver.Core/Core/Connections/BuildInfoResult.cs

@@ -28,13 +28,14 @@ namespace MongoDB.Driver.Core.Connections
     public sealed class ConnectionDescription : IEquatable<ConnectionDescription>
     {
         // fields
-        private readonly BuildInfoResult _buildInfoResult;
         private readonly IReadOnlyList<CompressorType> _compressors;
         private readonly ConnectionId _connectionId;
         private readonly HelloResult _helloResult;
         private readonly int _maxBatchCount;
         private readonly int _maxDocumentSize;
         private readonly int _maxMessageSize;
+        private readonly int _maxWireVersion;
+        private readonly int _minWireVersion;
         private readonly SemanticVersion _serverVersion;
         private readonly ObjectId? _serviceId;
 
@@ -44,33 +45,22 @@ public sealed class ConnectionDescription : IEquatable<ConnectionDescription>
         /// </summary>
         /// <param name="connectionId">The connection identifier.</param>
         /// <param name="helloResult">The hello result.</param>
-        /// <param name="buildInfoResult">The buildInfo result.</param>
-        public ConnectionDescription(ConnectionId connectionId, HelloResult helloResult, BuildInfoResult buildInfoResult)
+        public ConnectionDescription(ConnectionId connectionId, HelloResult helloResult)
         {
             _connectionId = Ensure.IsNotNull(connectionId, nameof(connectionId));
-            _buildInfoResult = Ensure.IsNotNull(buildInfoResult, nameof(buildInfoResult));
             _helloResult = Ensure.IsNotNull(helloResult, nameof(helloResult));
 
             _compressors = Ensure.IsNotNull(_helloResult.Compressions, "compressions");
             _maxBatchCount = helloResult.MaxBatchCount;
             _maxDocumentSize = helloResult.MaxDocumentSize;
             _maxMessageSize = helloResult.MaxMessageSize;
+            _maxWireVersion = helloResult.MaxWireVersion;
+            _minWireVersion = helloResult.MinWireVersion;
             _serviceId = helloResult.ServiceId;
-            _serverVersion = buildInfoResult.ServerVersion;
+            _serverVersion = WireVersion.ToServerVersion(_maxWireVersion);
         }
 
         // properties
-        /// <summary>
-        /// Gets the buildInfo result.
-        /// </summary>
-        /// <value>
-        /// The buildInfo result.
-        /// </value>
-        public BuildInfoResult BuildInfoResult
-        {
-            get { return _buildInfoResult; }
-        }
-
         /// <summary>
         /// Gets the available compressors.
         /// </summary>
@@ -157,12 +147,35 @@ public int MaxWireDocumentSize
             get { return _maxDocumentSize + 16 * 1024; }
         }
 
+        /// <summary>
+        /// Gets the maximum wire version.
+        /// </summary>
+        /// <value>
+        /// The maximum wire version.
+        /// </value>
+        public int MaxWireVersion
+        {
+            get { return _maxWireVersion; }
+        }
+
+        /// <summary>
+        /// Gets the minimum wire version.
+        /// </summary>
+        /// <value>
+        /// The minimum wire version.
+        /// </value>
+        public int MinWireVersion
+        {
+            get { return _minWireVersion; }
+        }
+
         /// <summary>
         /// Gets the server version.
         /// </summary>
         /// <value>
         /// The server version.
         /// </value>
+        [Obsolete("Use MaxWireVersion instead.")]
         public SemanticVersion ServerVersion
         {
             get { return _serverVersion; }
@@ -189,7 +202,6 @@ public bool Equals(ConnectionDescription other)
             }
 
             return
-                _buildInfoResult.Equals(other._buildInfoResult) &&
                 _connectionId.StructurallyEquals(other._connectionId) &&
                 _helloResult.Equals(other._helloResult);
         }
@@ -204,7 +216,6 @@ public override bool Equals(object obj)
         public override int GetHashCode()
         {
             return new Hasher()
-                .Hash(_buildInfoResult)
                 .Hash(_connectionId)
                 .Hash(_helloResult)
                 .GetHashCode();
@@ -217,7 +228,7 @@ public override int GetHashCode()
         /// <returns>A connection description.</returns>
         public ConnectionDescription WithConnectionId(ConnectionId value)
         {
-            return _connectionId.StructurallyEquals(value) ? this : new ConnectionDescription(value, _helloResult, _buildInfoResult);
+            return _connectionId.StructurallyEquals(value) ? this : new ConnectionDescription(value, _helloResult);
         }
     }
 }

src/MongoDB.Driver.Core/Core/Connections/ConnectionDescription.cs

@@ -122,10 +122,7 @@ public ConnectionDescription SendHello(IConnection connection, CancellationToken
                 throw new InvalidOperationException("Driver attempted to initialize in load balancing mode, but the server does not support this mode.");
             }
 
-            var buildInfoProtocol = CreateBuildInfoProtocol(_serverApi);
-            var buildInfoResult = new BuildInfoResult(buildInfoProtocol.Execute(connection, cancellationToken));
-
-            return new ConnectionDescription(connection.ConnectionId, helloResult, buildInfoResult);
+            return new ConnectionDescription(connection.ConnectionId, helloResult);
         }
 
         public async Task<ConnectionDescription> SendHelloAsync(IConnection connection, CancellationToken cancellationToken)
@@ -140,34 +137,10 @@ public async Task<ConnectionDescription> SendHelloAsync(IConnection connection,
                 throw new InvalidOperationException("Driver attempted to initialize in load balancing mode, but the server does not support this mode.");
             }
 
-            var buildInfoProtocol = CreateBuildInfoProtocol(_serverApi);
-            var buildInfoResult = new BuildInfoResult(await buildInfoProtocol.ExecuteAsync(connection, cancellationToken).ConfigureAwait(false));
-
-            return new ConnectionDescription(connection.ConnectionId, helloResult, buildInfoResult);
+            return new ConnectionDescription(connection.ConnectionId, helloResult);
         }
 
         // private methods
-        private CommandWireProtocol<BsonDocument> CreateBuildInfoProtocol(ServerApi serverApi)
-        {
-            var buildInfoServerApi =
-                serverApi != null
-                    ? new ServerApi(
-                        serverApi.Version,
-                        strict: false, // buildInfo is not part of server API version 1 so we must skip strict flag, otherwise initialize will fail
-                        deprecationErrors: serverApi.DeprecationErrors)
-                    : null;
-
-            var buildInfoCommand = new BsonDocument("buildInfo", 1);
-            var buildInfoProtocol = new CommandWireProtocol<BsonDocument>(
-                databaseNamespace: DatabaseNamespace.Admin,
-                command: buildInfoCommand,
-                secondaryOk: true,
-                resultSerializer: BsonDocumentSerializer.Instance,
-                messageEncoderSettings: null,
-                serverApi: buildInfoServerApi);
-            return buildInfoProtocol;
-        }
-
         private CommandWireProtocol<BsonDocument> CreateGetLastErrorProtocol(ServerApi serverApi)
         {
             var getLastErrorCommand = new BsonDocument("getLastError", 1);