UseDestinationValue is not inherited

UseDestinationValue doesn’t works when using Include<,> or IncludeBase<,>. Looks similar like here #2188, also used IncludeBase, but option is PreserveReferences.

Source/destination types

// Model
sealed class Root { public List<Element> Elements { get; } = new List<Element>(); }
class Element { public List<Item> Items { get; } = new List<Item>(); }
class ElementX : Element { }
sealed class Item { }

// Dto
sealed class RootDto { public List<ElementDto> Elements { get; } = new List<ElementDto>(); }
class ElementDto { public List<ItemDto> Items { get; } = new List<ItemDto>(); }
class ElementXDto : ElementDto { }
sealed class ItemDto { }

Mapping configuration

CreateMap<Root, RootDto>().ForMember(_ => _.Elements, _ => _.UseDestinationValue());
CreateMap<Element, ElementDto>().ForMember(_ => _.Items, _ => _.UseDestinationValue());
CreateMap<ElementX, ElementXDto>().IncludeBase<Element, ElementDto>();
CreateMap<Item, ItemDto>();

Version: 6.1.1

Expected behavior

When mapping Root to RootDto, for each source Element in Elements will be created ElementDto (ElementXDto for ElementX), and it’s Items collection will be populated by mapped objects from source collection.

Actual behavior

For ElemenDto colelction populated, but for ElemenXDto collection is empty.

Steps to reproduce

var config = new MapperConfiguration(cfg =>
{
    cfg.CreateMap<Root, RootDto>().ForMember(_ => _.Elements, _ => _.UseDestinationValue());
    cfg.CreateMap<Element, ElementDto>().ForMember(_ => _.Items, _ => _.UseDestinationValue());
    cfg.CreateMap<ElementX, ElementXDto>().IncludeBase<Element, ElementDto>();
    cfg.CreateMap<Item, ItemDto>();
});
config.AssertConfigurationIsValid();
var mapper = config.CreateMapper();

var source = new Root
{
    Elements =
        {
            new Element { Items = { new Item(), new Item(), new Item() } }, // 3 items
            new ElementX { Items = { new Item(), new Item(), new Item() } } // 3 items
        }
};

var target = mapper.Map<RootDto>(source);

As result:

source.Elements[0]
{MapperTestApp.Program.Element}
    Items: Count = 3
source.Elements[1]
{MapperTestApp.Program.ElementX}
    Items: Count = 3

target.Elements[0]
{MapperTestApp.Program.ElementDto}
    Items: Count = 3
target.Elements[1]
{MapperTestApp.Program.ElementXDto}
    Items: Count = 0

Note

Same if exact map ElementX to ElementXDto. Problem can be resolved by adding UseDestinationValue into ElementX to ElementXDto mapping, but why??? I almost configured it for Element to ElementDto mapping, and ElementX to ElementXDto mapping should include it. It looks like I need to configure same things twice, and this is simple example with just one derived class. In this case Include or IncludeBase looks useless, or works incorrect. Same in #2188, but used option is PreserveReferences.

[lbargaoanu]

Let’s start simple with a PR to inherit the setting and DontUseDestinationValue. Please open a new issue.

[lock[bot]]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.