Merge pull request MapsterMapper#37 from chaowlert/master

Add descriptive exception when map immutable type

src/Mapster.Tests/WhenMappingPrimitives.cs

@@ -60,6 +60,50 @@ public void ValueType_String_Object_Is_Always_Primitive()
  targetDto.Obj.ShouldBeSameAs(sourceDto.Obj);
  }
 
+ [Test]
+ public void Immutable_Class_With_No_Mapping_Should_Error()
+ {
+ try
+ {
+ TypeAdapterConfig.GlobalSettings.Clear();
+ TypeAdapterConfig<ImmutableA, ImmutableB>.NewConfig().Compile();
+ Assert.Fail();
+ }
+ catch (InvalidOperationException exception)
+ {
+ exception.ToString().Contains("MapWith").ShouldBeTrue();
+ }
+ }
+
+ [Test]
+ public void Able_To_Map_Immutable_Class_With_MapWith()
+ {
+ TypeAdapterConfig.GlobalSettings.Clear();
+ TypeAdapterConfig<ImmutableA, ImmutableB>.NewConfig()
+ .MapWith(src => new ImmutableB(src.Name))
+ .Compile();
+ }
+
+ public class ImmutableA
+ {
+ public ImmutableA(string name)
+ {
+ this.Name = name;
+ }
+
+ public string Name { get; }
+ }
+
+ public class ImmutableB
+ {
+ public ImmutableB(string name)
+ {
+ this.Name = name;
+ }
+
+ public string Name { get; }
+ }
+
  public class TestA
  {
  public Byte[] Bytes { get; set; }

src/Mapster/TypeAdapterSetter.cs

@@ -108,6 +108,13 @@ public TypeAdapterSetter<TSource, TDestination> ConstructUsing(Expression<Func<T
  public TypeAdapterSetter<TSource, TDestination> MapWith(Expression<Func<TSource, TDestination>> converterFactory)
  {
  Settings.ConverterFactory = arg => converterFactory;
+
+ if (Settings.ConverterToTargetFactory == null)
+ {
+ var dest = Expression.Parameter(typeof (TDestination));
+ Settings.ConverterToTargetFactory = arg => Expression.Lambda(converterFactory.Body, converterFactory.Parameters[0], dest);
+ }
+
  return this;
  }
 

src/Mapster/Utils/ReflectionUtils.cs

@@ -163,6 +163,10 @@ public static Expression BuildUnderlyingTypeConvertExpression(Expression source,
  }
  catch { }
 
+ if (srcType.GetInterfaces().All(type => type != typeof (IConvertible)))
+ throw new InvalidOperationException(
+ $"Cannot convert immutable type, please consider using 'MapWith' method to create mapping: TSource: {sourceType} TDestination: {destinationType}");
+
  //using Convert
  if (destType == typeof(bool))
  return CreateConvertMethod("ToBoolean", srcType, destType, source);