RMG060 — Multiple user-mappings discovered without specifying an explicit default

Multiple user-mappings for the same type pair are discovered without specifying an explicit default. Mapperly needs to now which mapping it should use.

To specify a default apply [UserMapping(Default = true)].

See also user-implemented mappings.

Example

Two mappings from Car to CarDto are defined. When Mapperly needs to map from Car to CarDto in CarsToCarDtos it needs to know whether to use CarToCarDto or CarToCarDtoIgnoreId. Apply [UserMapping(Default = true)] to the mapping which Mapperly should use in such cases.

Invalid

[Mapper]
public partial class CarMapper
{
  public partial List<CarDto> CarsToCarDtos(List<Car> cars);

  public partial CarDto CarToCarDto(Car car);

  [MapperIgnoreSource(nameof(Car.Id))]
  public partial CarDto CarToCarDtoIgnoreId(Car car);
}

Fixed

[Mapper]
public partial class CarMapper
{
  public partial List<CarDto> CarsToCarDtos(List<Car> cars);

  [UserMapping(Default = true)]
  public partial CarDto CarToCarDto(Car car);

  [MapperIgnoreSource(nameof(Car.Id))]
  public partial CarDto CarToCarDtoIgnoreId(Car car);
}