fixes

Author: KirillKurdyukov

src/Ydb.Sdk/src/Ado/Session/ImplicitSessionSource.cs

@@ -25,7 +25,8 @@ public ValueTask<ISession> OpenSession(CancellationToken cancellationToken)
 
         return TryAcquireLease()
             ? new ValueTask<ISession>(new ImplicitSession(_driver, this))
-            : throw new YdbException("The implicit session source has been shut down.");
+            : throw new ObjectDisposedException(nameof(ImplicitSessionSource),
+                "The implicit session source has been closed.");
     }
 
     private bool TryAcquireLease()

src/Ydb.Sdk/src/Ado/Session/PoolingSessionSource.cs

@@ -135,7 +135,7 @@ private async ValueTask<ISession> RentAsync(CancellationToken cancellationToken)
                 ), useSynchronizationContext: false
             );
             await using var disposeRegistration = _disposeCts.Token.Register(
-                () => waiterTcs.TrySetException(new YdbException("The session source has been shut down.")),
+                () => waiterTcs.TrySetException(ObjectDisposedException),
                 useSynchronizationContext: false
             );
             session = await waiterTcs.Task.ConfigureAwait(false);
@@ -159,7 +159,7 @@ private async ValueTask<ISession> RentAsync(CancellationToken cancellationToken)
             try
             {
                 if (IsDisposed)
-                    throw new YdbException("The session source has been shutdown.");
+                    throw ObjectDisposedException;
 
                 var session = _sessionFactory.NewSession(this);
                 await session.Open(cancellationToken);
@@ -306,6 +306,9 @@ public async ValueTask DisposeAsync()
                                    "This may indicate a connection leak or suspended operations.");
         }
     }
+    
+    private Exception ObjectDisposedException => 
+        new ObjectDisposedException(nameof(PoolingSessionSource<T>), "The session source has been closed.");
 }
 
 internal interface IPoolingSessionFactory<T> : IAsyncDisposable where T : PoolingSessionBase<T>

src/Ydb.Sdk/test/Ydb.Sdk.Ado.Tests/Session/PoolingSessionSourceMockTests.cs

@@ -141,12 +141,12 @@ public async Task DisposeAsync_Cancel_WaitersSession()
         Assert.Equal(0, mockFactory.NumSession);
         for (var i = 0; i < maxSessionSize; i++)
         {
-            Assert.Equal("The session source has been shut down.",
-                (await Assert.ThrowsAsync<YdbException>(() => waitingSessionTasks[i])).Message);
+            Assert.StartsWith("The session source has been closed.",
+                (await Assert.ThrowsAsync<ObjectDisposedException>(() => waitingSessionTasks[i])).Message);
         }
 
-        Assert.Equal("The session source has been shut down.",
-            (await Assert.ThrowsAsync<YdbException>(async () => await sessionSource.OpenSession())).Message);
+        Assert.StartsWith("The session source has been closed.",
+            (await Assert.ThrowsAsync<ObjectDisposedException>(async () => await sessionSource.OpenSession())).Message);
     }
 
     [Fact]
@@ -187,9 +187,9 @@ public async Task StressTest_DisposeAsync_Close_Driver()
                         await Task.Yield();
                         Assert.False(disposeCalled);
                     }
-                    catch (YdbException e)
+                    catch (ObjectDisposedException e)
                     {
-                        Assert.Equal("The session source has been shut down.", e.Message);
+                        Assert.StartsWith("The session source has been closed.", e.Message);
                     }
                     catch (OperationCanceledException)
                     {
@@ -202,7 +202,7 @@ public async Task StressTest_DisposeAsync_Close_Driver()
             Assert.True(disposeCalled);
         }
     }
-    
+
     [Fact]
     public async Task DisposeAsync_WhenSessionIsLeaked_ThrowsYdbExceptionWithTimeoutMessage()
     {
@@ -216,9 +216,9 @@ public async Task DisposeAsync_WhenSessionIsLeaked_ThrowsYdbExceptionWithTimeout
                 return ValueTask.CompletedTask;
             }
         };
-        var settings = new YdbConnectionStringBuilder {  MaxSessionPool = maxSessionSize };
+        var settings = new YdbConnectionStringBuilder { MaxSessionPool = maxSessionSize };
         var sessionSource = new PoolingSessionSource<MockPoolingSession>(mockFactory, settings);
-        
+
 #pragma warning disable CA2012
         _ = sessionSource.OpenSession(CancellationToken.None);
 #pragma warning restore CA2012
@@ -227,8 +227,8 @@ public async Task DisposeAsync_WhenSessionIsLeaked_ThrowsYdbExceptionWithTimeout
                      "This may indicate a connection leak or suspended operations.",
             (await Assert.ThrowsAsync<YdbException>(async () => await sessionSource.DisposeAsync())).Message);
         Assert.True(disposeCalled);
-        Assert.Equal("The session source has been shut down.", (await Assert.ThrowsAsync<YdbException>(
-            () => sessionSource.OpenSession(CancellationToken.None).AsTask())).Message);
+        await Assert.ThrowsAsync<ObjectDisposedException>(() =>
+            sessionSource.OpenSession(CancellationToken.None).AsTask());
     }
 
     [Fact]

src/Ydb.Sdk/test/Ydb.Sdk.Ado.Tests/Session/YdbImplicitStressTests.cs

@@ -66,7 +66,6 @@ public async Task DisposeAsync_WhenSessionIsLeaked_ThrowsYdbExceptionWithTimeout
                      "This may indicate a connection leak or suspended operations.",
             (await Assert.ThrowsAsync<YdbException>(async () => await source.DisposeAsync())).Message);
         Assert.True(_isDisposed);
-        Assert.Equal("The implicit session source has been shut down.", (await Assert.ThrowsAsync<YdbException>(
-            () => source.OpenSession(CancellationToken.None).AsTask())).Message);
+        await Assert.ThrowsAsync<ObjectDisposedException>(() => source.OpenSession(CancellationToken.None).AsTask());
     }
 }