revert #2050 - see #2049 for more details (#2070)

* revert #2050 - see #2049 for more details

Author: mgravell

Dapper/SqlMapper.cs

@@ -193,9 +193,7 @@ public TypeMapEntry(DbType dbType, TypeMapEntryFlags flags)
             public static readonly TypeMapEntry
                 DoNotSet = new((DbType)(-2), TypeMapEntryFlags.None),
                 DoNotSetFieldValue = new((DbType)(-2), TypeMapEntryFlags.UseGetFieldValue),
-                DecimalFieldValue = new(DbType.Decimal, TypeMapEntryFlags.SetType | TypeMapEntryFlags.UseGetFieldValue),
-                StringFieldValue = new(DbType.String, TypeMapEntryFlags.SetType | TypeMapEntryFlags.UseGetFieldValue),
-                BinaryFieldValue = new(DbType.Binary, TypeMapEntryFlags.SetType | TypeMapEntryFlags.UseGetFieldValue);
+                DecimalFieldValue = new(DbType.Decimal, TypeMapEntryFlags.SetType | TypeMapEntryFlags.UseGetFieldValue);
 
             public static implicit operator TypeMapEntry(DbType dbType)
                 => new(dbType, TypeMapEntryFlags.SetType);
@@ -221,13 +219,13 @@ static SqlMapper()
                 [typeof(double)] = DbType.Double,
                 [typeof(decimal)] = DbType.Decimal,
                 [typeof(bool)] = DbType.Boolean,
-                [typeof(string)] = TypeMapEntry.StringFieldValue,
+                [typeof(string)] = DbType.String,
                 [typeof(char)] = DbType.StringFixedLength,
                 [typeof(Guid)] = DbType.Guid,
                 [typeof(DateTime)] = TypeMapEntry.DoNotSet,
                 [typeof(DateTimeOffset)] = DbType.DateTimeOffset,
                 [typeof(TimeSpan)] = TypeMapEntry.DoNotSet,
-                [typeof(byte[])] = TypeMapEntry.BinaryFieldValue,
+                [typeof(byte[])] = DbType.Binary,
                 [typeof(byte?)] = DbType.Byte,
                 [typeof(sbyte?)] = DbType.SByte,
                 [typeof(short?)] = DbType.Int16,
@@ -3928,7 +3926,12 @@ public static void ThrowDataException(Exception ex, int index, IDataReader reade
                         }
                         else
                         {
-                            formattedValue = Convert.ToString(value) + " - " + Type.GetTypeCode(value.GetType());
+                            formattedValue = Convert.ToString(value) + " - " + Identify(value.GetType());
+                        }
+                        static string Identify(Type type)
+                        {
+                            var tc = Type.GetTypeCode(type);
+                            return tc == TypeCode.Object ? type.Name : tc.ToString();
                         }
                     }
                     catch (Exception valEx)

tests/Dapper.Tests/TypeHandlerTests.cs

@@ -28,12 +28,18 @@ public void TestChangingDefaultStringTypeMappingToAnsiString()
 
             SqlMapper.PurgeQueryCache();
 
-            SqlMapper.AddTypeMap(typeof(string), DbType.AnsiString, true); // Change Default String Handling to AnsiString
-            var result02 = connection.Query<string>(sql, param).FirstOrDefault();
-            Assert.Equal("varchar", result02);
+            SqlMapper.AddTypeMap(typeof(string), DbType.AnsiString, false); // Change Default String Handling to AnsiString
+            try
+            {
+                var result02 = connection.Query<string>(sql, param).FirstOrDefault();
+                Assert.Equal("varchar", result02);
 
-            SqlMapper.PurgeQueryCache();
-            SqlMapper.AddTypeMap(typeof(string), DbType.String, true);  // Restore Default to Unicode String
+                SqlMapper.PurgeQueryCache();
+            }
+            finally
+            {
+                SqlMapper.AddTypeMap(typeof(string), DbType.String, false); // Restore Default to Unicode String
+            }
         }
 
         [Fact]
@@ -46,13 +52,18 @@ public void TestChangingDefaultStringTypeMappingToAnsiStringFirstOrDefault()
             Assert.Equal("nvarchar", result01);
 
             SqlMapper.PurgeQueryCache();
+            SqlMapper.AddTypeMap(typeof(string), DbType.AnsiString, false); // Change Default String Handling to AnsiString
+            try
+            {
+                var result02 = connection.QueryFirstOrDefault<string>(sql, param);
+                Assert.Equal("varchar", result02);
 
-            SqlMapper.AddTypeMap(typeof(string), DbType.AnsiString, true); // Change Default String Handling to AnsiString
-            var result02 = connection.QueryFirstOrDefault<string>(sql, param);
-            Assert.Equal("varchar", result02);
-
-            SqlMapper.PurgeQueryCache();
-            SqlMapper.AddTypeMap(typeof(string), DbType.String, true);  // Restore Default to Unicode String
+                SqlMapper.PurgeQueryCache();
+            }
+            finally
+            {
+                SqlMapper.AddTypeMap(typeof(string), DbType.String, false); // Restore Default to Unicode String
+            }
         }
 
         [Fact]
@@ -643,7 +654,7 @@ public void Issue149_TypeMismatch_SequentialAccess()
         {
             Guid guid = Guid.Parse("cf0ef7ac-b6fe-4e24-aeda-a2b45bb5654e");
             var ex = Assert.ThrowsAny<Exception>(() => connection.Query<Issue149_Person>("select @guid as Id", new { guid }).First());
-            Assert.Equal("Error parsing column 0 (Id=n/a - Unable to cast object of type 'System.Guid' to type 'System.String'.)", ex.Message);
+            Assert.Equal("Error parsing column 0 (Id=cf0ef7ac-b6fe-4e24-aeda-a2b45bb5654e - Guid)", ex.Message);
         }
 
         public class Issue149_Person { public string? Id { get; set; } }