Allow disabling Firebird driver parameter casting

The NHibernate Firebird driver does hack SQL commands for explicitly
casting their parameters. This may cause issues in some cases, while,
depending on the application, it may not be required. See #1886.

Author: fredericDelaporte

doc/reference/modules/configuration.xml

@@ -1009,6 +1009,28 @@ var session = sessions.OpenSession(conn);
                             </para>
                         </entry>
                     </row>
+                    <row>
+                        <entry>
+                            <literal>firebird.disable_parameter_casting</literal>
+                        </entry>
+                        <entry>
+                            <para>
+                                Firebird with FirebirdSql.Data.FirebirdClient may be unable to determine the type
+                                of parameters in many circumstances, unless they are explicitly casted in the SQL
+                                query. To avoid this trouble, the NHibernate <literal>FirebirdClientDriver</literal> parses SQL
+                                commands for detecting parameters in them and adding an explicit SQL cast around
+                                parameters which may trigger the issue.
+                            </para>
+                            <para>
+                                Defaults to <literal>false</literal>.
+                                For disabling this behavior, set this setting to true.
+                            </para>
+                            <para>
+                                <emphasis role="strong">eg.</emphasis>
+                                <literal>true</literal> | <literal>false</literal>
+                            </para>
+                        </entry>
+                    </row>
                     <row>
                         <entry>
                             <literal>oracle.use_n_prefixed_types_for_unicode</literal>

src/NHibernate.Test/Async/DriverTest/FirebirdClientDriverFixture.cs

@@ -25,6 +25,7 @@ public class FirebirdClientDriverFixtureAsync
 	{
 		private string _connectionString;
 		private FirebirdClientDriver _driver;
+		private FirebirdClientDriver _driverWithoutCasting;
 
 		[OneTimeSetUp]
 		public void OneTimeSetup()
@@ -38,6 +39,10 @@ public void OneTimeSetup()
 			_driver = new FirebirdClientDriver();
 			_driver.Configure(cfg.Properties);
 			_connectionString = cfg.GetProperty("connection.connection_string");
+
+			_driverWithoutCasting = new FirebirdClientDriver();
+			cfg.SetProperty(Cfg.Environment.FirebirdDisableParameterCasting, "true");
+			_driverWithoutCasting.Configure(cfg.Properties);
 		}
 
 		[Test]

src/NHibernate.Test/DriverTest/FirebirdClientDriverFixture.cs

@@ -13,6 +13,7 @@ public class FirebirdClientDriverFixture
 	{
 		private string _connectionString;
 		private FirebirdClientDriver _driver;
+		private FirebirdClientDriver _driverWithoutCasting;
 
 		[OneTimeSetUp]
 		public void OneTimeSetup()
@@ -26,6 +27,10 @@ public void OneTimeSetup()
 			_driver = new FirebirdClientDriver();
 			_driver.Configure(cfg.Properties);
 			_connectionString = cfg.GetProperty("connection.connection_string");
+
+			_driverWithoutCasting = new FirebirdClientDriver();
+			cfg.SetProperty(Cfg.Environment.FirebirdDisableParameterCasting, "true");
+			_driverWithoutCasting.Configure(cfg.Properties);
 		}
 
 		[Test]
@@ -206,6 +211,66 @@ public void AdjustCommand_ParameterWithinIn_ParameterIsNotCasted()
 			}
 		}
 
+		[Test]
+		public void AdjustCommand_StringParametersWithinConditionalSelect_NotCastedWhenDisabled()
+		{
+			using (var cmd = BuildSelectCaseCommand(SqlTypeFactory.GetString(255)))
+			{
+				var originalSql = cmd.CommandText;
+				_driver.AdjustCommand(cmd);
+
+				Assert.That(cmd.CommandText, Is.EqualTo(originalSql));
+			}
+		}
+
+		[Test]
+		public void AdjustCommand_IntParametersWithinConditionalSelect_NotCastedWhenDisabled()
+		{
+			using (var cmd = BuildSelectCaseCommand(SqlTypeFactory.Int32))
+			{
+				var originalSql = cmd.CommandText;
+				_driver.AdjustCommand(cmd);
+
+				Assert.That(cmd.CommandText, Is.EqualTo(originalSql));
+			}
+		}
+
+		[Test]
+		public void AdjustCommand_ParameterWithinSelectConcat_NotCastedWhenDisabled()
+		{
+			using (var cmd = BuildSelectConcatCommand(SqlTypeFactory.GetString(255)))
+			{
+				var originalSql = cmd.CommandText;
+				_driver.AdjustCommand(cmd);
+
+				Assert.That(cmd.CommandText, Is.EqualTo(originalSql));
+			}
+		}
+
+		[Test]
+		public void AdjustCommand_ParameterWithinSelectAddFunction_NotCastedWhenDisabled()
+		{
+			using (var cmd = BuildSelectAddCommand(SqlTypeFactory.GetString(255)))
+			{
+				var originalSql = cmd.CommandText;
+				_driver.AdjustCommand(cmd);
+
+				Assert.That(cmd.CommandText, Is.EqualTo(originalSql));
+			}
+		}
+
+		[Test]
+		public void AdjustCommand_InsertWithParamsInSelect_NotCastedWhenDisabled()
+		{
+			using (var cmd = BuildInsertWithParamsInSelectCommand(SqlTypeFactory.Int32))
+			{
+				var originalSql = cmd.CommandText;
+				_driver.AdjustCommand(cmd);
+
+				Assert.That(cmd.CommandText, Is.EqualTo(originalSql));
+			}
+		}
+
 		private DbConnection MakeConnection()
 		{
 			var result = _driver.CreateConnection();

src/NHibernate/Cfg/Environment.cs

@@ -266,6 +266,20 @@ public static string Version
 		/// </remarks>
 		public const string OracleUseNPrefixedTypesForUnicode = "oracle.use_n_prefixed_types_for_unicode";
 
+		/// <summary>
+		/// <para>
+		/// Firebird with FirebirdSql.Data.FirebirdClient may be unable to determine the type
+		/// of parameters in many circumstances, unless they are explicitly casted in the SQL
+		/// query. To avoid this trouble, the NHibernate <c>FirebirdClientDriver</c> parses SQL
+		/// commands for detecting parameters in them and adding an explicit SQL cast around
+		/// parameters which may trigger the issue.
+		/// </para>
+		/// <para>
+		/// For disabling this behavior, set this setting to true.
+		/// </para>
+		/// </summary>
+		public const string FirebirdDisableParameterCasting = "firebird.disable_parameter_casting";
+
 		/// <summary>
 		/// <para>Set whether tracking the session id or not. When <see langword="true"/>, each session 
 		/// will have an unique <see cref="Guid"/> that can be retrieved by <see cref="ISessionImplementor.SessionId"/>,

src/NHibernate/Driver/FirebirdClientDriver.cs

@@ -9,6 +9,7 @@
 using NHibernate.SqlCommand;
 using NHibernate.SqlTypes;
 using NHibernate.Util;
+using Environment = NHibernate.Cfg.Environment;
 
 namespace NHibernate.Driver
 {
@@ -40,6 +41,8 @@ public class FirebirdClientDriver : ReflectionBasedDriver
 		private static readonly Regex _castCandidateRegEx = new Regex(CAST_PARAMS_EXP, RegexOptions.IgnoreCase);
 		private readonly FirebirdDialect _fbDialect = new FirebirdDialect();
 
+		private bool _disableParameterCasting;
+
 		/// <summary>
 		/// Initializes a new instance of the <see cref="FirebirdClientDriver"/> class.
 		/// </summary>
@@ -59,6 +62,8 @@ public override void Configure(IDictionary<string, string> settings)
 		{
 			base.Configure(settings);
 			_fbDialect.Configure(settings);
+
+			_disableParameterCasting = PropertiesHelper.GetBoolean(Environment.FirebirdDisableParameterCasting, settings);
 		}
 
 		public override bool UseNamedPrefixInSql => true;
@@ -80,6 +85,9 @@ public override DbCommand GenerateCommand(CommandType type, SqlString sqlString,
 		{
 			var command = base.GenerateCommand(type, sqlString, parameterTypes);
 
+			if (_disableParameterCasting)
+				return command;
+
 			var expWithParams = GetStatementsWithCastCandidates(command.CommandText);
 			if (!string.IsNullOrWhiteSpace(expWithParams))
 			{

src/NHibernate/nhibernate-configuration.xsd

@@ -188,6 +188,18 @@
 												</xs:documentation>
 											</xs:annotation>
 										</xs:enumeration>
+										<xs:enumeration value="firebird.disable_parameter_casting">
+											<xs:annotation>
+												<xs:documentation>
+													Firebird with FirebirdSql.Data.FirebirdClient may be unable to determine the type
+													of parameters in many circumstances, unless they are explicitly casted in the SQL
+													query. To avoid this trouble, the NHibernate FirebirdClientDriver parses SQL
+													commands for detecting parameters in them and adding an explicit SQL cast around
+													parameters which may trigger the issue.
+													For disabling this behavior, set this setting to true.
+												</xs:documentation>
+											</xs:annotation>
+										</xs:enumeration>
 										<xs:enumeration value="sql_types.keep_datetime">
 											<xs:annotation>
 												<xs:documentation>