feat: add EnableImplicitSession flag support with parsing tests

Author: LiamHamsters

src/Ydb.Sdk/src/Ado/YdbCommand.cs

@@ -215,11 +215,31 @@ protected override async Task<DbDataReader> ExecuteDbDataReaderAsync(CommandBeha
             throw new InvalidOperationException("Transaction mismatched! (Maybe using another connection)");
         }
 
-        var ydbDataReader = await YdbDataReader.CreateYdbDataReader(
-            await YdbConnection.Session
-                .ExecuteQuery(preparedSql.ToString(), ydbParameters, execSettings, transaction?.TransactionControl),
-            YdbConnection.OnNotSuccessStatusCode, transaction, cancellationToken
-        );
+        var useImplicit = YdbConnection.EnableImplicitSession && transaction is null;
+        var session = YdbConnection.GetExecutionSession(useImplicit);
+
+        YdbDataReader ydbDataReader;
+        try
+        {
+            var execResult = await session.ExecuteQuery(
+                preparedSql.ToString(),
+                ydbParameters,
+                execSettings,
+                transaction?.TransactionControl
+            );
+
+            ydbDataReader = await YdbDataReader.CreateYdbDataReader(
+                execResult,
+                YdbConnection.OnNotSuccessStatusCode,
+                transaction,
+                cancellationToken
+            );
+        }
+        finally
+        {
+            if (useImplicit)
+                session.Close();
+        }
 
         YdbConnection.LastReader = ydbDataReader;
         YdbConnection.LastCommand = CommandText;

src/Ydb.Sdk/src/Ado/YdbConnection.cs

@@ -38,6 +38,11 @@ internal ISession Session
     }
 
     private ISession _session = null!;
+    
+    internal bool EnableImplicitSession => ConnectionStringBuilder.EnableImplicitSession;
+    
+    internal ISession GetExecutionSession(bool useImplicit)
+        => useImplicit ? new ImplicitSession(Session.Driver) : Session;
 
     public YdbConnection()
     {

src/Ydb.Sdk/src/Ado/YdbConnectionStringBuilder.cs

@@ -41,6 +41,7 @@ private void InitDefaultValues()
         _maxReceiveMessageSize = GrpcDefaultSettings.MaxReceiveMessageSize;
         _disableDiscovery = GrpcDefaultSettings.DisableDiscovery;
         _disableServerBalancer = false;
+        _enableImplicitSession = false;
     }
 
     public string Host
@@ -315,6 +316,18 @@ public int CreateSessionTimeout
 
     private int _createSessionTimeout;
 
+    public bool EnableImplicitSession
+    {
+        get => _enableImplicitSession;
+        set
+        {
+            _enableImplicitSession = value;
+            SaveValue(nameof(EnableImplicitSession), value);
+        }
+    }
+
+    private bool _enableImplicitSession;
+
     public ILoggerFactory? LoggerFactory { get; init; }
 
     public ICredentialsProvider? CredentialsProvider { get; init; }
@@ -491,6 +504,9 @@ static YdbConnectionOption()
             AddOption(new YdbConnectionOption<bool>(BoolExtractor,
                     (builder, disableServerBalancer) => builder.DisableServerBalancer = disableServerBalancer),
                 "DisableServerBalancer", "Disable Server Balancer");
+            AddOption(new YdbConnectionOption<bool>(BoolExtractor,
+                    (builder, enableImplicit) => builder.EnableImplicitSession = enableImplicit),
+                "EnableImplicitSession", "ImplicitSession");
         }
 
         private static void AddOption(YdbConnectionOption option, params string[] keys)

src/Ydb.Sdk/test/Ydb.Sdk.Ado.Tests/YdbConnectionStringBuilderTests.cs

@@ -28,6 +28,7 @@ public void InitDefaultValues_WhenEmptyConstructorInvoke_ReturnDefaultConnection
         Assert.False(ydbConnectionStringBuilder.DisableDiscovery);
         Assert.False(ydbConnectionStringBuilder.DisableServerBalancer);
         Assert.False(ydbConnectionStringBuilder.UseTls);
+        Assert.False(ydbConnectionStringBuilder.EnableImplicitSession);
     }
 
     [Fact]
@@ -50,7 +51,7 @@ public void InitConnectionStringBuilder_WhenExpectedKeys_ReturnUpdatedConnection
             "ConnectTimeout=30;KeepAlivePingDelay=30;KeepAlivePingTimeout=60;" +
             "EnableMultipleHttp2Connections=true;" +
             "MaxSendMessageSize=1000000;MaxReceiveMessageSize=1000000;" +
-            "DisableDiscovery=true;DisableServerBalancer=true;"
+            "DisableDiscovery=true;DisableServerBalancer=true;EnableImplicitSession=true;"
         );
 
         Assert.Equal(2135, connectionString.Port);
@@ -74,9 +75,10 @@ public void InitConnectionStringBuilder_WhenExpectedKeys_ReturnUpdatedConnection
                      "ConnectTimeout=30;KeepAlivePingDelay=30;KeepAlivePingTimeout=60;" +
                      "EnableMultipleHttp2Connections=True;" +
                      "MaxSendMessageSize=1000000;MaxReceiveMessageSize=1000000;" +
-                     "DisableDiscovery=True;DisableServerBalancer=True", connectionString.ConnectionString);
+                     "DisableDiscovery=True;DisableServerBalancer=True;EnableImplicitSession=True", connectionString.ConnectionString);
         Assert.True(connectionString.DisableDiscovery);
         Assert.True(connectionString.DisableServerBalancer);
+        Assert.True(connectionString.EnableImplicitSession);
     }
 
     [Fact]

src/Ydb.Sdk/test/Ydb.Sdk.Ado.Tests/YdbConnectionTests.cs

@@ -483,4 +483,48 @@ public async Task BulkUpsertImporter_ThrowsOnNonexistentTable()
 
         await Assert.ThrowsAsync<YdbException>(async () => { await importer.FlushAsync(); });
     }
+    
+    [Fact]
+    public void EnableImplicitSession_WhenSetViaPrimaryKey_ParsesAndAppearsInConnectionString()
+    {
+        var csb = new YdbConnectionStringBuilder("EnableImplicitSession=true;Host=server;Port=2135;");
+        Assert.True(csb.EnableImplicitSession);
+
+        Assert.Contains("EnableImplicitSession=True", csb.ConnectionString);
+        Assert.Contains("Host=server", csb.ConnectionString); 
+        Assert.Contains("Port=2135", csb.ConnectionString);
+    }
+    
+    [Fact]
+    public void EnableImplicitSession_WhenSetViaAlias_ParsesAndNormalizesKey()
+    {
+        var csb = new YdbConnectionStringBuilder("ImplicitSession=on;Host=server;Port=2135;");
+        Assert.True(csb.EnableImplicitSession);
+
+        var s = csb.ConnectionString;
+
+        Assert.Contains("EnableImplicitSession=True", s);
+
+        var parts = s.Split(';', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
+        Assert.DoesNotContain(parts, p => p.StartsWith("ImplicitSession=", StringComparison.OrdinalIgnoreCase));
+
+        Assert.Contains("Host=server", s);
+        Assert.Contains("Port=2135", s);
+    }
+
+    [Theory]
+    [InlineData("true",  true)]
+    [InlineData("True",  true)]
+    [InlineData("on",    true)]
+    [InlineData("1",     true)]
+    [InlineData("false", false)]
+    [InlineData("False", false)]
+    [InlineData("off",   false)]
+    [InlineData("0",     false)]
+    public void EnableImplicitSession_StringBooleanVariants_AreParsed(string value, bool expected)
+    {
+        var csb = new YdbConnectionStringBuilder($"EnableImplicitSession={value};");
+        Assert.Equal(expected, csb.EnableImplicitSession);
+        Assert.Contains($"EnableImplicitSession={(expected ? "True" : "False")}", csb.ConnectionString);
+    }
 }