Support char-valued parameters. Fixes #412

Author: bgrainger

src/MySqlConnector/MySql.Data.MySqlClient/MySqlParameter.cs

@@ -191,6 +191,23 @@ internal void AppendSqlString(BinaryWriter writer, StatementPreparerOptions opti
 				writer.WriteUtf8(stringValue.Replace("\\", "\\\\").Replace("'", "\\'"));
 				writer.Write((byte) '\'');
 			}
+			else if (Value is char charValue)
+			{
+				writer.Write((byte) '\'');
+				switch (charValue)
+				{
+				case '\'':
+				case '\\':
+					writer.Write((byte) '\\');
+					writer.Write((byte) charValue);
+					break;
+
+				default:
+					writer.WriteUtf8(charValue.ToString());
+					break;
+				}
+				writer.Write((byte) '\'');
+			}
 			else if (Value is byte || Value is sbyte || Value is short || Value is int || Value is long || Value is ushort || Value is uint || Value is ulong || Value is decimal)
 			{
 				writer.WriteUtf8("{0}".FormatInvariant(Value));

tests/SideBySide/QueryTests.cs

@@ -767,6 +767,62 @@ public void OutputParameter()
 			}
 		}
 
+		[Fact]
+		public void CharParameter()
+		{
+			m_database.Connection.Execute(@"drop table if exists char_test;
+create table char_test(id integer not null primary key, char1 char(1) not null, char4 char(4) not null, varchar1 varchar(1) not null, varchar4 varchar(4) not null) collate utf8mb4_bin;
+insert into char_test (id, char1, char4, varchar1, varchar4) VALUES (1, '\'', 'b', 'c', 'Σ'), (2, 'e', '\\', '""', 'h');
+");
+
+			using (var command = new MySqlCommand("select id from char_test where char1 = @ch;", m_database.Connection))
+			{
+				command.Parameters.AddWithValue("@ch", '\'');
+				using (var reader = command.ExecuteReader())
+				{
+					Assert.True(reader.Read());
+					Assert.Equal(1, reader.GetInt32(0));
+					Assert.False(reader.Read());
+				}
+			}
+
+			using (var command = new MySqlCommand("select id from char_test where char4 = @ch;", m_database.Connection))
+			{
+				command.Parameters.AddWithValue("@ch", '\\');
+				using (var reader = command.ExecuteReader())
+				{
+					Assert.True(reader.Read());
+					Assert.Equal(2, reader.GetInt32(0));
+					Assert.False(reader.Read());
+				}
+			}
+
+			using (var command = new MySqlCommand("select id from char_test where varchar1 = @ch;", m_database.Connection))
+			{
+				command.Parameters.AddWithValue("@ch", '"');
+				using (var reader = command.ExecuteReader())
+				{
+					Assert.True(reader.Read());
+					Assert.Equal(2, reader.GetInt32(0));
+					Assert.False(reader.Read());
+				}
+			}
+
+#if !BASELINE
+			// can't repro test failure locally, but it fails on Appveyor
+			using (var command = new MySqlCommand("select id from char_test where varchar4 = @ch;", m_database.Connection))
+			{
+				command.Parameters.AddWithValue("@ch", 'Σ');
+				using (var reader = command.ExecuteReader())
+				{
+					Assert.True(reader.Read());
+					Assert.Equal(1, reader.GetInt32(0));
+					Assert.False(reader.Read());
+				}
+			}
+#endif
+		}
+
 		[Fact]
 		public void EnumParameter()
 		{