Follow the ADO.NET contract for HasRows, RecordsAffected, OCTETS GetFieldType and RemoveAt

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

@@ -535,4 +535,70 @@ public async Task GetFieldValueTest()
 			await transaction.RollbackAsync();
 		}
 	}
+
+	[Test]
+	public async Task HasRowsIsFalseForAnEmptyResultTest()
+	{
+		// DbDataReader.HasRows: "true if the DbDataReader contains one or more rows; otherwise false."
+		await using (var command = new FbCommand("select INT_FIELD from TEST where 1 = 0", Connection))
+		{
+			await using (var reader = await command.ExecuteReaderAsync())
+			{
+				Assert.IsFalse(reader.HasRows);
+				Assert.IsFalse(await reader.ReadAsync());
+			}
+		}
+	}
+
+	[Test]
+	public async Task HasRowsDoesNotSkipTheFirstRowTest()
+	{
+		await using (var command = new FbCommand("select INT_FIELD from TEST where INT_FIELD in (1, 2) order by INT_FIELD", Connection))
+		{
+			await using (var reader = await command.ExecuteReaderAsync())
+			{
+				Assert.IsTrue(reader.HasRows);
+				Assert.IsTrue(reader.HasRows);
+				Assert.IsTrue(await reader.ReadAsync());
+				Assert.AreEqual(1, reader.GetInt32(0));
+				Assert.IsTrue(reader.Read());
+				Assert.AreEqual(2, reader.GetInt32(0));
+				Assert.IsFalse(reader.Read());
+				Assert.IsTrue(reader.HasRows, "HasRows describes the result, not the current position");
+			}
+		}
+	}
+
+	[Test]
+	public async Task RecordsAffectedIsMinusOneForSelectTest()
+	{
+		// DbDataReader.RecordsAffected: "-1 for SELECT statements; 0 if no rows were affected or the statement failed."
+		await using (var command = new FbCommand("select INT_FIELD from TEST where 1 = 0", Connection))
+		{
+			var reader = await command.ExecuteReaderAsync();
+			while (await reader.ReadAsync())
+			{ }
+			await reader.CloseAsync();
+			Assert.AreEqual(-1, reader.RecordsAffected);
+		}
+	}
+
+	[Test]
+	public async Task GetFieldTypeMatchesGetValueForOctetsTest()
+	{
+		// IDataRecord.GetFieldType: "the type of Object that would be returned from GetValue."
+		await using (var command = new FbCommand("select cast('ab' as varchar(10) character set octets), cast('ab' as char(4) character set octets) from rdb$database", Connection))
+		{
+			await using (var reader = await command.ExecuteReaderAsync())
+			{
+				Assert.IsTrue(await reader.ReadAsync());
+				for (var i = 0; i < reader.FieldCount; i++)
+				{
+					Assert.AreEqual(typeof(byte[]), reader.GetValue(i).GetType());
+					Assert.AreEqual(typeof(byte[]), reader.GetFieldType(i));
+				}
+			}
+		}
+	}
 }
+

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

@@ -26,6 +26,30 @@ namespace FirebirdSql.Data.FirebirdClient.Tests;
 [NoServerCategory]
 public class FbParameterCollectionTests
 {
+	[TestCase(-1)]
+	[TestCase(0)]
+	[TestCase(1)]
+	public void RemoveAtInvalidIndexThrowsArgumentOutOfRangeTest(int index)
+	{
+		// IList.RemoveAt: ArgumentOutOfRangeException when "index is not a valid index in the IList".
+		var command = new FbCommand();
+		if (index == 1)
+		{
+			command.Parameters.Add("@p1", 1);
+		}
+
+		var ex = Assert.Throws<ArgumentOutOfRangeException>(() => command.Parameters.RemoveAt(index));
+		Assert.AreEqual("index", ex.ParamName);
+		Assert.AreEqual(index == 1 ? 1 : 0, command.Parameters.Count);
+	}
+
+	[Test]
+	public void RemoveAtUnknownNameThrowsIndexOutOfRangeTest()
+	{
+		var command = new FbCommand();
+		Assert.Throws<IndexOutOfRangeException>(() => command.Parameters.RemoveAt("@missing"));
+	}
+
 	[Test]
 	public void AddTest()
 	{

src/FirebirdSql.Data.FirebirdClient/Common/DbField.cs

@@ -549,6 +549,12 @@ public void FixNull()
 
 	public Type GetSystemType()
 	{
+		// SetValue stores CHAR and VARCHAR in the OCTETS character set as byte[], so that is the type GetValue returns.
+		if ((SqlType == IscCodes.SQL_TEXT || SqlType == IscCodes.SQL_VARYING) && (Charset?.IsOctetsCharset ?? false) && DbDataType != DbDataType.Guid)
+		{
+			return typeof(byte[]);
+		}
+
 		return TypeHelper.GetTypeFromDbDataType(DbDataType);
 	}
 

src/FirebirdSql.Data.FirebirdClient/FirebirdClient/FbCommand.cs

@@ -263,6 +263,24 @@ internal int RecordsAffected
 		}
 	}
 
+	/// <summary>
+	/// The rows an INSERT, UPDATE or DELETE affected, or -1 for any other statement (DbCommand.ExecuteNonQuery: "For all
+	/// other types of statements, the return value is -1"; DbDataReader.RecordsAffected: "-1 for SELECT statements").
+	/// </summary>
+	internal int StatementRecordsAffected
+	{
+		get
+		{
+			return _statement?.StatementType switch
+			{
+				DbStatementType.Insert => RecordsAffected,
+				DbStatementType.Update => RecordsAffected,
+				DbStatementType.Delete => RecordsAffected,
+				_ => -1,
+			};
+		}
+	}
+
 	internal bool IsDisposed
 	{
 		get { return _disposed; }
@@ -529,13 +547,7 @@ public override int ExecuteNonQuery()
 			}
 		}
 
-		return _statement.StatementType switch
-		{
-			DbStatementType.Insert => RecordsAffected,
-			DbStatementType.Update => RecordsAffected,
-			DbStatementType.Delete => RecordsAffected,
-			_ => -1,
-		};
+		return StatementRecordsAffected;
 	}
 	public override async Task<int> ExecuteNonQueryAsync(CancellationToken cancellationToken)
 	{
@@ -566,13 +578,7 @@ public override async Task<int> ExecuteNonQueryAsync(CancellationToken cancellat
 			}
 		}
 
-		return _statement.StatementType switch
-		{
-			DbStatementType.Insert => RecordsAffected,
-			DbStatementType.Update => RecordsAffected,
-			DbStatementType.Delete => RecordsAffected,
-			_ => -1,
-		};
+		return StatementRecordsAffected;
 	}
 
 	public new FbDataReader ExecuteReader() => ExecuteReader(CommandBehavior.Default);

src/FirebirdSql.Data.FirebirdClient/FirebirdClient/FbDataReader.cs

@@ -51,7 +51,10 @@ public sealed class FbDataReader : DbDataReader
 	private bool _eof;
 	private bool _isClosed;
 	private int _position;
-	private int _recordsAffected;
+	private int _recordsAffected = -1;
+	private DbValue[] _peekedRow;
+	private bool _hasPeekedRow;
+	private bool _hasRows;
 	private Dictionary<string, int> _columnsIndexesOrdinal;
 	private Dictionary<string, int> _columnsIndexesOrdinalCI;
 
@@ -102,9 +105,25 @@ public override int Depth
 		}
 	}
 
+	/// <summary>
+	/// DbDataReader.HasRows: "true if the DbDataReader contains one or more rows; otherwise false." Before the first
+	/// Read this fetches one row ahead; Read then returns that row.
+	/// </summary>
 	public override bool HasRows
 	{
-		get { return _command.HasFields; }
+		get
+		{
+			if (!_hasRows && !_isClosed && !_hasPeekedRow && _position == StartPosition && _command != null && _command.HasFields && !IsCommandBehavior(CommandBehavior.SchemaOnly))
+			{
+				using (var explicitCancellation = ExplicitCancellation.Enter(CancellationToken.None, _command.Cancel))
+				{
+					_peekedRow = _command.Fetch();
+				}
+				_hasPeekedRow = true;
+				_hasRows = _peekedRow != null;
+			}
+			return _hasRows;
+		}
 	}
 
 	public override bool IsClosed
@@ -166,6 +185,8 @@ public override void Close()
 			_command = null;
 			_connection = null;
 			_row = null;
+			_peekedRow = null;
+			_hasPeekedRow = false;
 			_schemaTable = null;
 			_fields = null;
 		}
@@ -195,6 +216,8 @@ public override async Task CloseAsync()
 			_command = null;
 			_connection = null;
 			_row = null;
+			_peekedRow = null;
+			_hasPeekedRow = false;
 			_schemaTable = null;
 			_fields = null;
 		}
@@ -229,10 +252,11 @@ public override bool Read()
 		{
 			using (var explicitCancellation = ExplicitCancellation.Enter(CancellationToken.None, _command.Cancel))
 			{
-				_row = _command.Fetch();
+				_row = TakePeekedRow(out var peeked) ? peeked : _command.Fetch();
 				if (_row != null)
 				{
 					_position++;
+					_hasRows = true;
 					return true;
 				}
 				else
@@ -259,10 +283,11 @@ public override async Task<bool> ReadAsync(CancellationToken cancellationToken)
 		{
 			using (var explicitCancellation = ExplicitCancellation.Enter(cancellationToken, _command.Cancel))
 			{
-				_row = await _command.FetchAsync(explicitCancellation.CancellationToken).ConfigureAwait(false);
+				_row = TakePeekedRow(out var peeked) ? peeked : await _command.FetchAsync(explicitCancellation.CancellationToken).ConfigureAwait(false);
 				if (_row != null)
 				{
 					_position++;
+					_hasRows = true;
 					return true;
 				}
 				else
@@ -1012,14 +1037,24 @@ private FbDbType GetProviderType(int i)
 		return (FbDbType)_fields[i].DbDataType;
 	}
 
+	private bool TakePeekedRow(out DbValue[] row)
+	{
+		row = _peekedRow;
+		var hadPeekedRow = _hasPeekedRow;
+		_peekedRow = null;
+		_hasPeekedRow = false;
+		return hadPeekedRow;
+	}
+
 	private void UpdateRecordsAffected()
 	{
 		if (_command != null && !_command.IsDisposed)
 		{
-			if (_command.RecordsAffected != -1)
+			var recordsAffected = _command.StatementRecordsAffected;
+			if (recordsAffected != -1)
 			{
 				_recordsAffected = _recordsAffected == -1 ? 0 : _recordsAffected;
-				_recordsAffected += _command.RecordsAffected;
+				_recordsAffected += recordsAffected;
 			}
 		}
 	}

src/FirebirdSql.Data.FirebirdClient/FirebirdClient/FbParameterCollection.cs

@@ -254,9 +254,10 @@ public override void Remove(object value)
 
 	public override void RemoveAt(int index)
 	{
-		if (index < 0 || index > Count)
+		// IList.RemoveAt: ArgumentOutOfRangeException when "index is not a valid index in the IList".
+		if (index < 0 || index >= Count)
 		{
-			throw new IndexOutOfRangeException("The specified index does not exist.");
+			throw new ArgumentOutOfRangeException(nameof(index), index, "The specified index does not exist.");
 		}
 
 		var parameter = this[index];
@@ -266,7 +267,13 @@ public override void RemoveAt(int index)
 
 	public override void RemoveAt(string parameterName)
 	{
-		RemoveAt(IndexOf(parameterName));
+		var index = IndexOf(parameterName);
+		if (index < 0)
+		{
+			throw new IndexOutOfRangeException("The specified index does not exist.");
+		}
+
+		RemoveAt(index);
 	}
 
 	public void CopyTo(FbParameter[] array, int index)