Scene related. Enum component can not be reflected.

[automeowtion]

Is it correct to believe that enums can not be component and reflected? And wrapping enums with struct is the solution?

DETAIL:

In Reflection cleanup #1536, @Davier mentioned that

#[reflect_value(...)] should not be used for structs, they need #[reflect(...)] instead. I have no idea what happens when using both attributes on the same type, but I don't think it's supposed to happen.

From what I gathered:

1. structs need #[reflect(...)]
2. enums need #[reflect_value(...)]
3. #[reflect(...)] and #[reflect_value(...)] don't mix
4. for a type to be used as component and reflected it needs #[derive(Component)] and #[reflect(Component)]

Which seems to mean that enums can not be used as components and reflected at the same time, because according to point number 3, #[reflect(Component)] and #[reflect_value(...)] can not co-exist. To test the above, I save a scene with an enum with the following derives

#[derive(Component, Serialize, Deserialize, PartialEq, Eq, Hash, Clone, Copy, Reflect)]
#[reflect_value(Serialize, Deserialize, PartialEq, Hash)]
#[reflect(Component)]

which causes the following panic:

[...type] does not support ReflectValue serialization

What works: remove #[reflect(Component)], and wrap the enum in a struct pub struct EnumTWrapper(pub EnumT);, which is then inserted as component.

[hymm]

There's a draft PR to add reflection to enums here: #1347. Not sure about the status.

[Davier]

You can use #[reflect_value(Component)] on enums:

#[derive(Component, Serialize, Deserialize, PartialEq, Eq, Hash, Clone, Copy, Reflect)]
#[reflect_value(Component, Serialize, Deserialize, PartialEq, Hash)]

[alice-i-cecile]

Do we still need #1347 then?

[Davier]

Yes. That PR will allow to reflect what is inside an enum using #[reflect()], like we already do for a reflected struct's fields.
Currently we have to use #[reflect_value()], which treats the enums like black boxes (that´s why they need to implement Serialize and Deserialize, while structs don't).