Handle when IO operations are cancelled - fix #1212

src/FirebirdSql.Data.FirebirdClient.Tests/FbConnectionTests.cs

@@ -619,6 +619,40 @@ public async Task ConnectionTimeoutUsingCancellationToken()
 		}
 	}
 
+	[Test]
+	public async Task PooledConnectionUsableAfterCancelledBeginTransaction()
+	{
+		if (!EnsureServerType(FbServerType.Default))
+			return;
+
+		// The cancellation token reaches the socket read, so the transaction response stays unread.
+		var csb = BuildConnectionStringBuilder(ServerType, Compression, WireCrypt);
+		csb.Pooling = true;
+		csb.MinPoolSize = 0;
+		csb.MaxPoolSize = 1;
+		var connectionString = csb.ToString();
+		FbConnection.ClearPool(connectionString);
+
+		using (var cancellation = new CancellationTokenSource())
+		await using (var connection = new FbConnection(connectionString))
+		{
+			await connection.OpenAsync();
+			var beginning = connection.BeginTransactionAsync(cancellation.Token);
+			cancellation.Cancel();
+			Assert.CatchAsync<OperationCanceledException>(async () => await beginning);
+		}
+
+		await using (var connection = new FbConnection(connectionString))
+		{
+			await connection.OpenAsync();
+			await using (var command = connection.CreateCommand())
+			{
+				command.CommandText = "select 1 from rdb$database";
+				Assert.AreEqual(1, Convert.ToInt32(await command.ExecuteScalarAsync()));
+			}
+		}
+	}
+
 	[Test]
 	public async Task SrpWithLeadingZeros()
 	{

src/FirebirdSql.Data.FirebirdClient/Client/Managed/FirebirdNetworkHandlingWrapper.cs

@@ -57,6 +57,7 @@ public FirebirdNetworkHandlingWrapper(IDataProvider dataProvider)
 
 	public int Read(byte[] buffer, int offset, int count)
 	{
+		CheckIOState();
 		if (_inputBuffer.Count < count)
 		{
 			var readBuffer = _readBuffer;
@@ -89,6 +90,7 @@ public int Read(byte[] buffer, int offset, int count)
 	}
 	public async ValueTask<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken = default)
 	{
+		CheckIOState();
 		if (_inputBuffer.Count < count)
 		{
 			var readBuffer = _readBuffer;
@@ -102,6 +104,11 @@ public async ValueTask<int> ReadAsync(byte[] buffer, int offset, int count, Canc
 				IOFailed = true;
 				throw;
 			}
+			catch (OperationCanceledException)
+			{
+				IOFailed = true;
+				throw;
+			}
 			if (read != 0)
 			{
 				if (_decryptor != null)
@@ -134,6 +141,7 @@ public ValueTask WriteAsync(byte[] buffer, int offset, int count, CancellationTo
 
 	public void Flush()
 	{
+		CheckIOState();
 		var buffer = _outputBuffer.ToArray();
 		_outputBuffer.Clear();
 		var count = buffer.Length;
@@ -159,6 +167,7 @@ public void Flush()
 	}
 	public async ValueTask FlushAsync(CancellationToken cancellationToken = default)
 	{
+		CheckIOState();
 		var buffer = _outputBuffer.ToArray();
 		_outputBuffer.Clear();
 		var count = buffer.Length;
@@ -181,6 +190,11 @@ public async ValueTask FlushAsync(CancellationToken cancellationToken = default)
 			IOFailed = true;
 			throw;
 		}
+		catch (OperationCanceledException)
+		{
+			IOFailed = true;
+			throw;
+		}
 	}
 
 	public void StartCompression()
@@ -196,6 +210,12 @@ public void StartEncryption(byte[] key)
 		_decryptor = CreateCipher(key);
 	}
 
+	void CheckIOState()
+	{
+		if (IOFailed)
+			throw new IOException("Error reading data from the connection.");
+	}
+
 	int ReadFromInputBuffer(byte[] buffer, int offset, int count)
 	{
 		var read = Math.Min(count, _inputBuffer.Count);

src/FirebirdSql.Data.FirebirdClient/FirebirdClient/FbConnection.cs

@@ -753,7 +753,17 @@ public override void Close()
 				}
 			}
 			catch
-			{ }
+			{
+				if (_innerConnection != null)
+				{
+					if (_options.Pooling)
+					{
+						FbConnectionPoolManager.Instance.Release(_innerConnection, returnToAvailable: false);
+					}
+
+					DisconnectEnlistedHelper();
+				}
+			}
 			finally
 			{
 				OnStateChange(_state, ConnectionState.Closed);
@@ -810,7 +820,17 @@ public override async Task CloseAsync()
 				}
 			}
 			catch
-			{ }
+			{
+				if (_innerConnection != null)
+				{
+					if (_options.Pooling)
+					{
+						FbConnectionPoolManager.Instance.Release(_innerConnection, false);
+					}
+
+					await DisconnectEnlistedHelper().ConfigureAwait(false);
+				}
+			}
 			finally
 			{
 				OnStateChange(_state, ConnectionState.Closed);

src/FirebirdSql.Data.FirebirdClient/FirebirdClient/FbConnectionInternal.cs

@@ -367,6 +367,11 @@ public async Task<FbTransaction> BeginTransactionAsync(IsolationLevel level, str
 			await DisposeTransactionAsync(cancellationToken).ConfigureAwait(false);
 			throw FbException.Create(ex);
 		}
+		catch (OperationCanceledException)
+		{
+			await DisposeTransactionAsync(CancellationToken.None).ConfigureAwait(false);
+			throw;
+		}
 
 		return _activeTransaction;
 	}
@@ -412,6 +417,11 @@ public async Task<FbTransaction> BeginTransactionAsync(FbTransactionOptions opti
 			await DisposeTransactionAsync(cancellationToken).ConfigureAwait(false);
 			throw FbException.Create(ex);
 		}
+		catch (OperationCanceledException)
+		{
+			await DisposeTransactionAsync(CancellationToken.None).ConfigureAwait(false);
+			throw;
+		}
 
 		return _activeTransaction;
 	}