Treat a property as nullable

[jamesfoster]

I need a way to treat a property as nullable even tho the source type declares it as non-nullable. The problem is I don't own the source type and in certain cases this "non-nullable" property is coming out as null 🙄.

Any help appreciated.

[latonz]

This is currently not possible with Mapperly. As a workaround you can exclude the property via the MapperIgnoreTarget/MapperIgnoreSource attributes and map it manually.

[jamesfoster]

Thanks, I've also noticed that when mapping a nullable struct to the same nullable struct it generates the following:

target.Prop = source.Prop ?? default;

This is interpreted as:

target.Prop = source.Prop ?? default(SomeStruct);

instead of:

target.Prop = source.Prop ?? default(Nullable<SomeStruct>); (or indeed just target.Prop = source.Prop)

So instead of null mapping to null, null actually maps to the default instance of the struct. In the case of a DateTime, null becomes 1970-01-01T00:00:00Z

[latonz]

This should be fixed in the latest pre-release (2.8.0-next.1), could you verify this?

[jamesfoster]

Yes, it's now correct 👍.

I updated the nuget reference to that version and re-built and it still came out as the same ?? default.

I had to restart VS to get it to use the new version it seems. Is that expected behaviour?

[latonz]

I think sometimes NuGet packages get cached but I'm not aware of the details, usually a version change of a package should also download the new package and load the new source generator.