bevy_reflect: Access Type from dyn PartialReflect

[MrGVSV]

Objective

The Type type was added in #14838 and acts like a TypeId that retains info of its TypePath. However, this was somewhat tedious to retrieve on a reflected value.

If you have a dyn Reflect, you have to do this:

value.reflect_type_info().ty()

And if all you have is a dyn PartialReflect, then you have to do this:

value.get_represented_type_info().map(TypeInfo::ty).copied()

And on top of that, this means that we can never get the Type of a dynamic type at runtime since dynamic types do not have a corresponding TypeInfo.

Compare this to TypePath, which via DynamicTypePath (a supertrait on PartialReflect), we can do this to get the type path of a dyn PartialReflect:

value.reflect_type_path()

And that will work for both dynamic and concrete types.

This should be true for Type as well.

Solution

This PR adds two new methods:

• PartialReflect::comptime_type
• PartialReflect::runtime_type

I chose the comptime and runtime prefixes because I wanted words that weren't as overloaded. I could have also gone with concrete and dynamic, but my worry was that dynamic_type would be too easily confused with our concept of a "dynamic type". And it's actually the opposite: this doesn't return the Type of the underlying dynamic type, but the Type of the concrete type the underlying dynamic type is proxying.

I'm open to feedback on the names!

I did try to unify the terminology to some extent by also making the following changes:

• PartialReflect::get_represented_type_info -> PartialReflect::runtime_type_info
• DynamicTyped::reflect_type_info -> DynamicTyped::comptime_type_info

Todo

• Add migration note once naming is finalized

Testing

Added unit tests for remote types.

---

Showcase

TODO

[github-actions]

It looks like your PR is a breaking change, but you didn't provide a migration guide.

Please review the instructions for writing migration guides, then expand or revise the content in the migration guides directory to reflect your changes.

[alice-i-cecile]

I quite like your choice of names, and the functionality is useful here :) I think we can stabilize those names.