GH-3530: The SAP SqlAnywhere driver does not implement DbDataReader.GetChar and incorrectly uses Convert without specifying an IFormatProvider. Wrap the SAP SqlAnywhere DbDataReader in a SqlAnywhereDbDataReader to correct these issues.

Author: David Ellingsworth

src/NHibernate/AdoNet/SqlAnywhereDbDataReader.cs

@@ -0,0 +1,60 @@
+using System;
+using System.Data.Common;
+using System.Globalization;
+
+namespace NHibernate.AdoNet
+{
+	/// <summary>
+	/// This is a wrapper for the DbDataReader returned by the SqlAnywhere driver.
+	/// The DbDataReader in the SqlAnywhere driver does not support the GetChar method,
+	/// and uses Convert.To* without specifying an <see cref="IFormatProvider"/>.
+	/// </summary>
+	public class SqlAnywhereDbDataReader : NoCharDbDataReader
+	{
+		public SqlAnywhereDbDataReader(DbDataReader reader) : base(reader) { }
+
+		public override float GetFloat(int ordinal)
+		{
+			var value = DataReader[ordinal];
+
+			return value switch
+			{
+				string s => float.Parse(s, CultureInfo.InvariantCulture),
+				_ => (float) value
+			};
+		}
+
+		public override double GetDouble(int ordinal)
+		{
+			var value = DataReader[ordinal];
+
+			return value switch
+			{
+				string s => double.Parse(s, CultureInfo.InvariantCulture),
+				_ => (double) value
+			};
+		}
+
+		public override decimal GetDecimal(int ordinal)
+		{
+			var value = DataReader[ordinal];
+
+			return value switch
+			{
+				string s => decimal.Parse(s, CultureInfo.InvariantCulture),
+				_ => (decimal) value
+			};
+		}
+
+		public override DateTime GetDateTime(int ordinal)
+		{
+			var value = DataReader[ordinal];
+
+			return value switch
+			{
+				string s => DateTime.Parse(s, CultureInfo.InvariantCulture),
+				_ => (DateTime) value
+			};
+		}
+	}
+}

src/NHibernate/Async/Driver/SapSQLAnywhere17Driver.cs

@@ -23,7 +23,7 @@ public override async Task<DbDataReader> ExecuteReaderAsync(DbCommand command, C
 			cancellationToken.ThrowIfCancellationRequested();
 			var reader = await (command.ExecuteReaderAsync(cancellationToken)).ConfigureAwait(false);
 
-			return new NoCharDbDataReader(reader);
+			return new SqlAnywhereDbDataReader(reader);
 		}
 	}
 }

src/NHibernate/Driver/SapSQLAnywhere17Driver.cs

@@ -22,7 +22,7 @@ public override DbDataReader ExecuteReader(DbCommand command)
 		{
 			var reader = command.ExecuteReader();
 
-			return new NoCharDbDataReader(reader);
+			return new SqlAnywhereDbDataReader(reader);
 		}
 	}
 }