ForAllPropertyMaps NullReferenceException

[zhyy2008z]

Source/destination types

//source type
public class Well
{
    //balabala...

    public SpecialTags SpecialTags { get; set; }


    //balabala...
}

[Flags]
public enum SpecialTags
{
    None = 0,

    SendState = 1,

    NotSendZeroWhenOpen = 2,
}

//destination type
public class PostPutWellViewModel
{
    //balabala...

    public SpecialTags[] SpecialTags { get; set; } = Array.Empty<SpecialTags>();

    //balabala...
}

Mapping configuration

public class MyAutoMapperProfile : Profile
{
    public MyAutoMapperProfile()
    {
        CreateMap<Well, PostPutWellViewModel>()
        .ReverseMap();
    }

}

class ArrayToEnum : IValueConverter<object, object>
{
    public object Convert(object sourceMember, ResolutionContext context)
    {
        return Enum.ToObject(sourceMember.GetType().GetElementType()!, ((int[])sourceMember).Aggregate(0, (p, n) => p | n));
    }
}

class EnumToArray : IValueConverter<object, object>
{
    public object Convert(object sourceMember, ResolutionContext context)
    {
        var list = Enum.GetValues(sourceMember.GetType()).Cast<Enum>().ToList();

        for (int i = list.Count - 1; i > -1; i--)
        {
            var e = (int)(object)list[i];
            if (e == 0 || (e & (int)sourceMember) != e)
                list.RemoveAt(i);
        }

        var r = Array.CreateInstance(sourceMember.GetType(), list.Count);
        for (int i = 0; i < list.Count; i++)
            r.SetValue(list[i], i);

        return r;
    }
}

//oops, throw null reference exception
var config = new AutoMapper.MapperConfiguration(cfg =>
{
    cfg.AddProfile<MyAutoMapperProfile>();

    cfg.Internal().ForAllPropertyMaps(pm => pm.SourceType != null && pm.SourceType.IsArray && pm.SourceType.GetElementType()!.IsEnum && pm.DestinationType.IsEnum || pm.SourceType != null && pm.SourceType.IsEnum && pm.DestinationType.IsArray && pm.DestinationType.GetElementType()!.IsEnum,
        (tm, mapper) =>
    {
        if (tm.SourceType.IsArray && tm.SourceType.GetElementType()!.IsEnum && tm.DestinationType.IsEnum)
        {
            mapper.ConvertUsing(new ArrayToEnum());
        }
        else if (tm.SourceType.IsEnum && tm.DestinationType.IsArray && tm.DestinationType.GetElementType()!.IsEnum)
        {
            mapper.ConvertUsing(new EnumToArray());
        }
    });
});

Version: 12.0.1

Expected behavior and Actual behavior

I recently upgraded AutoMapper from version 8.1.1 to version 12.0.1, and then the code that used to work properly has a null reference exception. I don't know if this is a design change or some kind of bug, please help me, thanks!

According to my test, this problem started from version 11. I made a demo of version 8.1.1 and 12.0.1 to demonstrate the problem, and the code is almost identical in both versions.

Steps to reproduce

var mapper = config.CreateMapper();

var well = new Well();
well.SpecialTags = SpecialTags.SendState;

var vm = mapper.Map<PostPutWellViewModel>(well);

demo: https://github.com/zhyy2008z/AutoMapper_Issue_Samples/raw/main/AutoMapper_Samples.rar

[lbargaoanu]

Try the MyGet build.
But that code seems terribly inefficient. Try a map instead or a custom object mapper.

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