FromReflect Ergonomics

[MrGVSV]

RENDERED

Derive FromReflect by default when deriving Reflect, add ReflectFromReflect type data, and make ReflectDeserializer easier to use.

[PROMETHIA-27]

Love this! I am fully behind and have wanted every feature here for a while.

[PROMETHIA-27]

I don't think so, but I wouldn't be opposed to adding construct() as a helper function which wraps over ReflectFromReflect.

[MrGVSV]

Yeah I agree that we should keep RFR. I decided to leave out the Future Possibilities section, but in it I originally described adding a ReflectFromWorldReflect type data to support a proposed FromWorldReflect trait. And my thought was that this would pair nicely with RFR without needing to create another method on TypeRegistration. (Left out that section because it seemed a bit off-topic, though, haha.)

And also, by keeping RFR we keep open the possibility of cloning and storing the type data outside the registry if needed.

[alice-i-cecile]

Please try to split your lines at the sentence / clause level; it makes reviewing and suggestions much more pleasant :)

[Nilirad]

Have you considered using the “static type” instead of “real type”? It seems to be a direct translation from dynamic vs static typing.

[MrGVSV]

Have you considered using the “static type” instead of “real type”? It seems to be a direct translation from dynamic vs static typing.

I did, but chose not to use it. My reasoning was that "static" feels like we should know the exact type at compile time. However, a dyn Reflect could still be a "real type", even though it isn't statically known.

[MrGVSV]

Please try to split your lines at the sentence / clause level; it makes reviewing and suggestions much more pleasant :)

Okay I split bascially every sentence across multiple lines (where I could). Typora hates me now lol, but hopefully that's more readable/reviewable 🙂

[raffaeleragni]

Any update on this? I am trying to deserialize some bevy basic types (eg Transform) but can't rewire the type from DynamicStruct, because it doesn't have ReflectFromReflect.

[MrGVSV]

Any update on this?

Unfortunately, there hasn't been much progress. While @cart has suggested more of an openness to merging FromReflect into the derive for Reflect, I haven't taken the time to update the RFC.

One reason I haven't updated it is because after coding the initial implementation in bevyengine/bevy#6056, I just found the RFC to be overkill. The actual changes are only a few hundred lines and most of it is cleanup. On top of that, ReflectFromReflect, which was part of this RFC, got merged on its own pretty easily.

So I could update this, but I may just close it out in favor of just using bevyengine/bevy#6056 to respond to any feedback. I'll probably rebase and update that PR relatively soon. Thoughts?

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I am trying to deserialize some bevy basic types (eg Transform) but can't rewire the type from DynamicStruct, because it doesn't have ReflectFromReflect.

If you want to make a PR adding in a ReflectFromReflect registration, I'm sure that will be easily accepted (basically a four line change to cover both Transform and GlobalTransform).

In the meantime, however, you can just manually register it for all your known types:

app.register_type_data::<Transform, ReflectFromReflect>();

[raffaeleragni]

Didn't know there was a workaround, that's actually great, thanks.

[MrGVSV]

Closing this out. See bevyengine/bevy#6056 (comment) for details.