[Merged by Bors] - bevy_reflect: Add ReflectFromReflect (v2)
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I like the idea but can't say I'm a fan of this name, "ReflectFromReflect" doesn't seem very intuitive to me. Maybe ConvertFromReflect, CastFromReflect, ValueFromReflect, TypeFromReflect? |
Yeah, I don't love the name. Unfortunately, there's not much we can do about this as the It'd be great if there was a way to get the types directly from the trait (e.g. So I think it's best to just keep this as is for now. You could maybe argue that |
jakobhellermann
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This a a pretty simple change (just one more ReflectX type data) and required for some use cases of Reflect.
I just wished this was registered by default, but that's a story for another time (maybe #6056)
PROMETHIA-27
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Dec 11, 2022
Co-authored-by: ira <JustTheCoolDude@gmail.com>
alice-i-cecile
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# Objective Resolves #4597 (based on the work from #6056 and a refresh of #4147) When using reflection, we may often end up in a scenario where we have a Dynamic representing a certain type. Unfortunately, we can't just call `MyType::from_reflect` as we do not have knowledge of the concrete type (`MyType`) at runtime. Such scenarios happen when we call `Reflect::clone_value`, use the reflection deserializers, or create the Dynamic type ourselves. ## Solution Add a `ReflectFromReflect` type data struct. This struct allows us to easily convert Dynamic representations of our types into their respective concrete instances. ```rust #[derive(Reflect, FromReflect)] #[reflect(FromReflect)] // <- Register `ReflectFromReflect` struct MyStruct(String); let type_id = TypeId::of::<MyStruct>(); // Register our type let mut registry = TypeRegistry::default(); registry.register::<MyStruct>(); // Create a concrete instance let my_struct = MyStruct("Hello world".to_string()); // `Reflect::clone_value` will generate a `DynamicTupleStruct` for tuple struct types let dynamic_value: Box<dyn Reflect> = my_struct.clone_value(); assert!(!dynamic_value.is::<MyStruct>()); // Get the `ReflectFromReflect` type data from the registry let rfr: &ReflectFromReflect = registry .get_type_data::<ReflectFromReflect>(type_id) .unwrap(); // Call `FromReflect::from_reflect` on our Dynamic value let concrete_value: Box<dyn Reflect> = rfr.from_reflect(&dynamic_value); assert!(concrete_value.is::<MyStruct>()); ``` ### Why this PR? ###### Why now? The three main reasons I closed #4147 were that: 1. Registering `ReflectFromReflect` is clunky (deriving `FromReflect` *and* registering `ReflectFromReflect`) 2. The ecosystem and Bevy itself didn't seem to pay much attention to deriving `FromReflect` 3. I didn't see a lot of desire from the community for such a feature However, as time has passed it seems 2 and 3 are not really true anymore. Bevy is internally adding lots more `FromReflect` derives, which should make this feature all the more useful. Additionally, I have seen a growing number of people look for something like `ReflectFromReflect`. I think 1 is still an issue, but not a horrible one. Plus it could be made much, much better using #6056. And I think splitting this feature out of #6056 could lead to #6056 being adopted sooner (or at least make the need more clear to users). ###### Why not just re-open #4147? The main reason is so that this PR can garner more attention than simply re-opening the old one. This helps bring fresh eyes to the PR for potentially more perspectives/reviews. --- ## Changelog * Added `ReflectFromReflect` Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
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ReflectFromReflect (v2)ReflectFromReflect (v2)
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Jan 22, 2023
# Objective Resolves bevyengine#4597 (based on the work from bevyengine#6056 and a refresh of bevyengine#4147) When using reflection, we may often end up in a scenario where we have a Dynamic representing a certain type. Unfortunately, we can't just call `MyType::from_reflect` as we do not have knowledge of the concrete type (`MyType`) at runtime. Such scenarios happen when we call `Reflect::clone_value`, use the reflection deserializers, or create the Dynamic type ourselves. ## Solution Add a `ReflectFromReflect` type data struct. This struct allows us to easily convert Dynamic representations of our types into their respective concrete instances. ```rust #[derive(Reflect, FromReflect)] #[reflect(FromReflect)] // <- Register `ReflectFromReflect` struct MyStruct(String); let type_id = TypeId::of::<MyStruct>(); // Register our type let mut registry = TypeRegistry::default(); registry.register::<MyStruct>(); // Create a concrete instance let my_struct = MyStruct("Hello world".to_string()); // `Reflect::clone_value` will generate a `DynamicTupleStruct` for tuple struct types let dynamic_value: Box<dyn Reflect> = my_struct.clone_value(); assert!(!dynamic_value.is::<MyStruct>()); // Get the `ReflectFromReflect` type data from the registry let rfr: &ReflectFromReflect = registry .get_type_data::<ReflectFromReflect>(type_id) .unwrap(); // Call `FromReflect::from_reflect` on our Dynamic value let concrete_value: Box<dyn Reflect> = rfr.from_reflect(&dynamic_value); assert!(concrete_value.is::<MyStruct>()); ``` ### Why this PR? ###### Why now? The three main reasons I closed bevyengine#4147 were that: 1. Registering `ReflectFromReflect` is clunky (deriving `FromReflect` *and* registering `ReflectFromReflect`) 2. The ecosystem and Bevy itself didn't seem to pay much attention to deriving `FromReflect` 3. I didn't see a lot of desire from the community for such a feature However, as time has passed it seems 2 and 3 are not really true anymore. Bevy is internally adding lots more `FromReflect` derives, which should make this feature all the more useful. Additionally, I have seen a growing number of people look for something like `ReflectFromReflect`. I think 1 is still an issue, but not a horrible one. Plus it could be made much, much better using bevyengine#6056. And I think splitting this feature out of bevyengine#6056 could lead to bevyengine#6056 being adopted sooner (or at least make the need more clear to users). ###### Why not just re-open bevyengine#4147? The main reason is so that this PR can garner more attention than simply re-opening the old one. This helps bring fresh eyes to the PR for potentially more perspectives/reviews. --- ## Changelog * Added `ReflectFromReflect` Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
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# Objective Resolves bevyengine#4597 (based on the work from bevyengine#6056 and a refresh of bevyengine#4147) When using reflection, we may often end up in a scenario where we have a Dynamic representing a certain type. Unfortunately, we can't just call `MyType::from_reflect` as we do not have knowledge of the concrete type (`MyType`) at runtime. Such scenarios happen when we call `Reflect::clone_value`, use the reflection deserializers, or create the Dynamic type ourselves. ## Solution Add a `ReflectFromReflect` type data struct. This struct allows us to easily convert Dynamic representations of our types into their respective concrete instances. ```rust #[derive(Reflect, FromReflect)] #[reflect(FromReflect)] // <- Register `ReflectFromReflect` struct MyStruct(String); let type_id = TypeId::of::<MyStruct>(); // Register our type let mut registry = TypeRegistry::default(); registry.register::<MyStruct>(); // Create a concrete instance let my_struct = MyStruct("Hello world".to_string()); // `Reflect::clone_value` will generate a `DynamicTupleStruct` for tuple struct types let dynamic_value: Box<dyn Reflect> = my_struct.clone_value(); assert!(!dynamic_value.is::<MyStruct>()); // Get the `ReflectFromReflect` type data from the registry let rfr: &ReflectFromReflect = registry .get_type_data::<ReflectFromReflect>(type_id) .unwrap(); // Call `FromReflect::from_reflect` on our Dynamic value let concrete_value: Box<dyn Reflect> = rfr.from_reflect(&dynamic_value); assert!(concrete_value.is::<MyStruct>()); ``` ### Why this PR? ###### Why now? The three main reasons I closed bevyengine#4147 were that: 1. Registering `ReflectFromReflect` is clunky (deriving `FromReflect` *and* registering `ReflectFromReflect`) 2. The ecosystem and Bevy itself didn't seem to pay much attention to deriving `FromReflect` 3. I didn't see a lot of desire from the community for such a feature However, as time has passed it seems 2 and 3 are not really true anymore. Bevy is internally adding lots more `FromReflect` derives, which should make this feature all the more useful. Additionally, I have seen a growing number of people look for something like `ReflectFromReflect`. I think 1 is still an issue, but not a horrible one. Plus it could be made much, much better using bevyengine#6056. And I think splitting this feature out of bevyengine#6056 could lead to bevyengine#6056 being adopted sooner (or at least make the need more clear to users). ###### Why not just re-open bevyengine#4147? The main reason is so that this PR can garner more attention than simply re-opening the old one. This helps bring fresh eyes to the PR for potentially more perspectives/reviews. --- ## Changelog * Added `ReflectFromReflect` Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
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## How This Works For the Bevy 0.10 release blog post (and for the first time ever), I'm publicly opening the doors to other people writing blog post sections. Specifically, if you worked on a feature in a substantial way and are interested in presenting it, you can now ask to claim a section by leaving a comment in this PR. If you claim a section, submit a pull request to the `release-0.10.0` branch in this repo. For the next week, we will be filling in sections (the release target is Saturday March 4th). Please don't claim a section if you don't plan on completing it within that timeline. Also don't claim a section if you weren't an active participant in the design and implementation of the change (unless you are a Maintainer or SME). I will claim any unclaimed sections. Try to match the style of previous release blog posts as much as possible. 1. Show, don't tell. Don't bombard people with information. Avoid large walls of text _and_ large walls of code. Prefer the pattern "byte sized description of one thing" -> "example code/picture/video contextualizing that one thing" -> repeat. Take readers on a journey step by simple step. 2. Don't use up reader's "mental bandwidth" without good reason. We can't afford page-long descriptions of minor bug fixes. If it isn't a "headliner change", keep the description short and sweet. If a change is self describing, let it do that (ex: We now support this new mesh shape primitive ... this is what it looks like). If it is a "headliner change", still try to keep it reasonable. We always have a lot to cover. 3. In slight competition with point (2), don't omit interesting technical information when it is truly fun and engaging. A good chunk of our users are highly technical and enjoy learning how the sausage is made. Try to strike a balance between "terse and simple" and "nerdy details". 4. When relevant, briefly describe the problem being solved first, then describe the solution we chose. This contextualizes the change and gives the feature value and purpose. 5. When possible, provide visuals. They create interest / keep people hooked / break up the monotony. 6. Record images and videos at the default bevy resolution (1280x720) 7. Provide an accurate listing of authors that meaningfully contributed to the feature. Try to sort in order of "contribution scale". This is hard to define, but try to be fair. When in doubt, ask other contributors, SMEs, and/or maintainers. 8. Provide numbers and graphs where possible. If something is faster, use numbers to back it up. We don't (yet) have automated graph generation in blog post style, so send data / info to me (@cart) if you want a graph made. ## Headliners Headliners are our "big ticket high importance / high profile" changes. They are listed briefly at the beginning of the blog post, their entries are roughly sorted "to the top", and they are given priority when it comes to "space in the blog post". If you think we missed something (or didn't prioritize something appropriately), let us know. * ECS Schedule v3 (previously known as "stageless") * Partial Android Support * Depth and Normal Prepass * Environment Map Lighting * Cascaded Shadow Maps * Distance and Atmospheric Fog * Smooth Skeletal Animation Transitions * Enable Parallel Pipelined Rendering * Windows as Entities * Renderer Optimizations * ECS Optimizations ## Sections These are the sections we will cover in the blog post. If a section has been claimed, it will have `(claimed by X)` in the title. If it is unclaimed it will have `(unclaimed)` in the title. Let us know if we missed a section. We don't cover every feature, but we should cover pretty much everything that would be interesting to users. Note that what is interesting or challenging to implement is not necessarily something that is relevant to our blog post readers. And sometimes the reverse is true! If you believe a section should be split up or reorganized, just bring it up here and we can discuss it. ### ~~Schedule V3 (claimed by @alice-i-cecile)~~ * [Migrate engine to Schedule v3][7267] * [Add `bevy_ecs::schedule_v3` module][6587] * [Stageless: fix unapplied systems][7446] * [Stageless: move final apply outside of spawned executor][7445] * Sets * Base Sets * [Base Sets][7466] * Reporting * [Report sets][7756] * [beter cycle reporting][7463] * Run Conditions * [Add condition negation][7559] * [And/Or][7605] * [Add more common run conditions][7579] * States * [States derive macro][7535] * System Piping Flexibility * [Support piping exclusive systems][7023] * [Allow piping run conditions][7547] ### ~~Depth and Normal Prepass (claimed by @IceSentry)~~ * [Add depth and normal prepass][6284] * [Move prepass functions to prepass_utils][7354] ### ~~Distance and Atmospheric Fog (claimed by @coreh)~~ * [Add Distance and Atmospheric Fog support][6412] ### ~~Cascaded Shadow Maps (claimed by @cart)~~ * [Cascaded shadow maps.][7064] * [Better cascades config defaults + builder, tweak example configs][7456] ### ~~Environment Map Lighting (claimed by @cart)~~ * [EnvironmentMapLight, BRDF Improvements][7051] * [Webgl2 support][7737] ### ~~Tonemapping options (claimed by @cart)~~ * [Initial tonemapping options][7594] ### ~~Android support + unification (claimed by @mockersf)~~ * [IOS, Android... same thing][7493] ### ~~Windows as Entities (claimed by @Aceeri)~~ * [Windows as Entities][5589] * [break feedback loop when moving cursor][7298] * [Fix `Window` feedback loop between the OS and Bevy][7517] ### ~~Enable Parallel Pipelined Rendering (claimed by @james7132)~~ * [Pipelined Rendering][6503] * [Stageless: add a method to scope to always run a task on the scope thread][7415] * [Separate Extract from Sub App Schedule][7046] ### ~~Smooth Skeletal Animation Transitions (claimed by @james7132)~~ * [Smooth Transition between Animations][6922] ### ~~Spatial Audio (claimed by @harudagondi)~~ * [Spatial Audio][6028] ### ~~Shader Processor Features (claimed by @cart)~~ * [Shader defs can now have a value][5900] * [Shaders can now have #else ifdef chains][7431] * [Define shader defs in shader][7518] ### ~~Shader Flexibility Improvements (claimed by @cart)~~ * [add ambient lighting hook][5428] * [Refactor Globals and View structs into separate shaders][7512] ### ~~Renderer Optimizations (claimed by @james7132)~~ * [bevy_pbr: Avoid copying structs and using registers in shaders][7069] * [Flatten render commands][6885] * [Replace UUID based IDs with a atomic-counted ones][6988] * [improve compile time by type-erasing wgpu structs][5950] * [Shrink DrawFunctionId][6944] * [Shrink ComputedVisibility][6305] * [Reduce branching in TrackedRenderPass][7053] * [Make PipelineCache internally mutable.][7205] * [Improve `Color::hex` performance][6940] * [Support recording multiple CommandBuffers in RenderContext][7248] * [Parallelized transform propagation][4775] * [Introduce detailed_trace macro, use in TrackedRenderPass][7639] * [Optimize color computation in prepare_uinodes][7311] * [Directly extract joints into SkinnedMeshJoints][6833] * [Parallelize forward kinematics animation systems][6785] * [Move system_commands spans into apply_buffers][6900] * [Reduce the use of atomics in the render phase][7084] ### ~~ECS Optimizations (claimed by @james7132 )~~ * [Remove redundant table and sparse set component IDs from Archetype][4927] * [Immutable sparse sets for metadata storage][4928] * [Replace BlobVec's swap_scratch with a swap_nonoverlapping][4853] * [Use T::Storage::STORAGE_TYPE to optimize out unused branches][6800] * [Remove unnecessary branching from bundle insertion][6902] * [Split Component Ticks][6547] * [use bevy_utils::HashMap for better performance. TypeId is predefined …][7642] * [Extend EntityLocation with TableId and TableRow][6681] * [Basic adaptive batching for parallel quer- [Speed up `CommandQueue` by storing commands more densely][6391]y iteration][4777] ### ~~Reflect Improvements (claimed by @cart)~~ * [bevy_reflect: Add `ReflectFromReflect` (v2)][6245] * [Add reflection support for VecDeque][6831] * [reflect: add `insert` and `remove` methods to `List`][7063] * [Add `remove` method to `Map` reflection trait.][6564] * [bevy_reflect: Fix binary deserialization not working for unit structs][6722] * [Add `TypeRegistrationDeserializer` and remove `BorrowedStr`][7094] * [bevy_reflect: Add simple enum support to reflection paths][6560] * [Enable deriving Reflect on structs with generic types][7364] * [bevy_reflect: Support tuple reflection paths][7324] * [bevy_reflect: Pre-parsed paths][7321] * [bevy_ecs: ReflectComponentFns without World][7206] ### ~~AsBindGroup Improvements (claimed by @cart)~~ * [Support storage buffers in derive `AsBindGroup`][6129] * [Support raw buffers in AsBindGroup][7701] ### ~~Cylinder Shape (claimed by @cart)~~ * [Add cylinder shape][6809] ### ~~Subdividable Plane Shape (claimed by @cart)~~ * [added subdivisions to shape::Plane][7546] ### ~~StandardMaterial Blend Modes (claimed by @coreh)~~ * [Standard Material Blend Modes][6644] ### ~~Configurable Visibility Component (claimed by @cart)~~ * [enum `Visibility` component][6320] ### Task Improvements (claimed by @cart) * [Fix panicking on another scope][6524] * [Add thread create/destroy callbacks to TaskPool][6561] * [Thread executor for running tasks on specific threads.][7087] * [await tasks to cancel][6696] * [Stageless: move MainThreadExecutor to schedule_v3][7444] * [Stageless: close the finish channel so executor doesn't deadlock][7448] ### ~~Upgrade to wgpu 0.15 (claimed by @cart)~~ * [Wgpu 0.15][7356] ### ~~Expose Bindless / Non-uniform Indexing Support (claimed by @cart)~~ * [Request WGPU Capabilities for Non-uniform Indexing][6995] ### ~~Cubic Spline (claimed by @aevyrie)~~ * [Bezier][7653] ### ~~Revamp Bloom (claimed by @JMS55)~~ * [Revamp bloom](bevyengine/bevy#6677) ### ~~Use Prepass Shaders for Shadows (claimed by @superdump)~~ * [use prepass shaders for shadows](bevyengine/bevy#7784) ### ~~AccessKit (claimed by @alice-i-cecile)~~ * [accesskit](bevyengine/bevy#6874) ### ~~Camera Output Modes (claimed by @cart)~~ * [camera output modes](bevyengine/bevy#7671) ### ~~SystemParam Improvements (claimed by @JoJoJet)~~ * [Make the `SystemParam` derive macro more flexible][6694] * [Add a `SystemParam` primitive for deferred mutations; allow `#[derive]`ing more types of SystemParam][6817] ### ~~Gamepad Improvements (claimed by @cart)~~ * [Gamepad events refactor][6965] * [add `Axis::devices` to get all the input devices][5400] ### ~~Input Methods (claimed by @cart)~~ * [add Input Method Editor support][7325] ### ~~Color Improvements (claimed by @cart)~~ * [Add LCH(ab) color space to `bevy_render::color::Color`][7483] * [Add a more familiar hex color entry][7060] ### ~~Split Up CorePlugin (claimed by @cart)~~ * [Break `CorePlugin` into `TaskPoolPlugin`, `TypeRegistrationPlugin`, `FrameCountPlugin`.][7083] ### ~~ExtractComponent Derive (claimed by @cart)~~ * [Extract component derive][7399] ### ~~Added OpenGL and DX11 Backends By Default (claimed by @cart)~~ * [add OpenGL and DX11 backends][7481] ### ~~UnsafeWorldCell (claimed by @BoxyUwU)~~ * [Move all logic to `UnsafeWorldCell`][7381] * [Rename `UnsafeWorldCellEntityRef` to `UnsafeEntityCell`][7568] ### ~~Entity Commands (claimed by @cart)~~ * [Add a trait for commands that run for a given `Entity`][7015] * [Add an extension trait to `EntityCommands` to update hierarchy while preserving `GlobalTransform`][7024] * [Add ReplaceChildren and ClearChildren EntityCommands][6035] ### ~~Iterate EntityRef (claimed by @james7132)~~ * [Allow iterating over with EntityRef over the entire World][6843] ### ~~Ref Queries (@JoJoJet)~~ * [Added Ref to allow immutable access with change detection][7097] ### ~~Taffy Upgrade (claimed by @cart)~~ * [Upgrade to Taffy 0.2][6743] ### ~~Relative Cursor Position (claimed by @cart)~~ * [Relative cursor position][7199] ### ~~Const UI Config (claimed by @cart)~~ * [Add const to methods and const defaults to bevy_ui][5542] ### ~~Examples (claimed by @cart)~~ * [Add pixelated Bevy to assets and an example][6408] * [Organized scene_viewer into plugins for reuse and organization][6936] ### ~~CI Improvements (claimed by @cart)~~ * [add rust-version for MSRV and CI job to check][6852] * [msrv: only send a message on failure during the actual msrv part][7532] * [Make CI friendlier][7398] * [Fix CI welcome message][7428] * [add an action to ask for a migration guide when one is missing][7507] ### ~~SMEs (@cart)~~ This was already covered in another blog post. Just briefly call out what they are and that this is the first release that used them. Link to the other blog post. * [Subject Matter Experts and new Bevy Org docs][7185] [4775]: bevyengine/bevy#4775 [4777]: bevyengine/bevy#4777 [4853]: bevyengine/bevy#4853 [4927]: bevyengine/bevy#4927 [4928]: bevyengine/bevy#4928 [5400]: bevyengine/bevy#5400 [5428]: bevyengine/bevy#5428 [5542]: bevyengine/bevy#5542 [5589]: bevyengine/bevy#5589 [5900]: bevyengine/bevy#5900 [5950]: bevyengine/bevy#5950 [6028]: bevyengine/bevy#6028 [6035]: bevyengine/bevy#6035 [6129]: bevyengine/bevy#6129 [6179]: bevyengine/bevy#6179 [6245]: bevyengine/bevy#6245 [6284]: bevyengine/bevy#6284 [6305]: bevyengine/bevy#6305 [6320]: bevyengine/bevy#6320 [6391]: bevyengine/bevy#6391 [6408]: bevyengine/bevy#6408 [6412]: bevyengine/bevy#6412 [6503]: bevyengine/bevy#6503 [6524]: bevyengine/bevy#6524 [6547]: bevyengine/bevy#6547 [6557]: bevyengine/bevy#6557 [6560]: bevyengine/bevy#6560 [6561]: bevyengine/bevy#6561 [6564]: bevyengine/bevy#6564 [6587]: bevyengine/bevy#6587 [6644]: bevyengine/bevy#6644 [6649]: bevyengine/bevy#6649 [6681]: bevyengine/bevy#6681 [6694]: bevyengine/bevy#6694 [6696]: bevyengine/bevy#6696 [6722]: bevyengine/bevy#6722 [6743]: bevyengine/bevy#6743 [6785]: bevyengine/bevy#6785 [6800]: bevyengine/bevy#6800 [6802]: bevyengine/bevy#6802 [6809]: bevyengine/bevy#6809 [6817]: bevyengine/bevy#6817 [6831]: bevyengine/bevy#6831 [6833]: bevyengine/bevy#6833 [6843]: bevyengine/bevy#6843 [6852]: bevyengine/bevy#6852 [6885]: bevyengine/bevy#6885 [6900]: bevyengine/bevy#6900 [6902]: bevyengine/bevy#6902 [6922]: bevyengine/bevy#6922 [6926]: bevyengine/bevy#6926 [6936]: bevyengine/bevy#6936 [6940]: bevyengine/bevy#6940 [6944]: bevyengine/bevy#6944 [6965]: bevyengine/bevy#6965 [6988]: bevyengine/bevy#6988 [6995]: bevyengine/bevy#6995 [7015]: bevyengine/bevy#7015 [7023]: bevyengine/bevy#7023 [7024]: bevyengine/bevy#7024 [7046]: bevyengine/bevy#7046 [7051]: bevyengine/bevy#7051 [7053]: bevyengine/bevy#7053 [7060]: bevyengine/bevy#7060 [7063]: bevyengine/bevy#7063 [7064]: bevyengine/bevy#7064 [7069]: bevyengine/bevy#7069 [7083]: bevyengine/bevy#7083 [7084]: bevyengine/bevy#7084 [7087]: bevyengine/bevy#7087 [7094]: bevyengine/bevy#7094 [7097]: bevyengine/bevy#7097 [7185]: bevyengine/bevy#7185 [7199]: bevyengine/bevy#7199 [7205]: bevyengine/bevy#7205 [7206]: bevyengine/bevy#7206 [7248]: bevyengine/bevy#7248 [7267]: bevyengine/bevy#7267 [7298]: bevyengine/bevy#7298 [7311]: bevyengine/bevy#7311 [7321]: bevyengine/bevy#7321 [7324]: bevyengine/bevy#7324 [7325]: bevyengine/bevy#7325 [7354]: bevyengine/bevy#7354 [7356]: bevyengine/bevy#7356 [7364]: bevyengine/bevy#7364 [7381]: bevyengine/bevy#7381 [7398]: bevyengine/bevy#7398 [7399]: bevyengine/bevy#7399 [7415]: bevyengine/bevy#7415 [7428]: bevyengine/bevy#7428 [7431]: bevyengine/bevy#7431 [7444]: bevyengine/bevy#7444 [7445]: bevyengine/bevy#7445 [7446]: bevyengine/bevy#7446 [7448]: bevyengine/bevy#7448 [7456]: bevyengine/bevy#7456 [7463]: bevyengine/bevy#7463 [7466]: bevyengine/bevy#7466 [7481]: bevyengine/bevy#7481 [7483]: bevyengine/bevy#7483 [7493]: bevyengine/bevy#7493 [7507]: bevyengine/bevy#7507 [7510]: bevyengine/bevy#7510 [7512]: bevyengine/bevy#7512 [7517]: bevyengine/bevy#7517 [7518]: bevyengine/bevy#7518 [7532]: bevyengine/bevy#7532 [7535]: bevyengine/bevy#7535 [7546]: bevyengine/bevy#7546 [7547]: bevyengine/bevy#7547 [7559]: bevyengine/bevy#7559 [7568]: bevyengine/bevy#7568 [7579]: bevyengine/bevy#7579 [7594]: bevyengine/bevy#7594 [7605]: bevyengine/bevy#7605 [7639]: bevyengine/bevy#7639 [7642]: bevyengine/bevy#7642 [7653]: bevyengine/bevy#7653 [7701]: bevyengine/bevy#7701 [7737]: bevyengine/bevy#7737 [7756]: bevyengine/bevy#7756 Co-authored-by: François <mockersf@gmail.com> Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com> Co-authored-by: Mike <mike.hsu@gmail.com> Co-authored-by: Boxy <supbscripter@gmail.com> Co-authored-by: IceSentry <c.giguere42@gmail.com> Co-authored-by: JoJoJet <21144246+JoJoJet@users.noreply.github.com> Co-authored-by: Aevyrie <aevyrie@gmail.com> Co-authored-by: James Liu <contact@jamessliu.com> Co-authored-by: Marco Buono <thecoreh@gmail.com> Co-authored-by: Aceeri <conmcclusk@gmail.com>
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# Objective **This implementation is based on bevyengine/rfcs#59 --- Resolves #4597 Full details and motivation can be found in the RFC, but here's a brief summary. `FromReflect` is a very powerful and important trait within the reflection API. It allows Dynamic types (e.g., `DynamicList`, etc.) to be formed into Real ones (e.g., `Vec<i32>`, etc.). This mainly comes into play concerning deserialization, where the reflection deserializers both return a `Box<dyn Reflect>` that almost always contain one of these Dynamic representations of a Real type. To convert this to our Real type, we need to use `FromReflect`. It also sneaks up in other ways. For example, it's a required bound for `T` in `Vec<T>` so that `Vec<T>` as a whole can be made `FromReflect`. It's also required by all fields of an enum as it's used as part of the `Reflect::apply` implementation. So in other words, much like `GetTypeRegistration` and `Typed`, it is very much a core reflection trait. The problem is that it is not currently treated like a core trait and is not automatically derived alongside `Reflect`. This makes using it a bit cumbersome and easy to forget. ## Solution Automatically derive `FromReflect` when deriving `Reflect`. Users can then choose to opt-out if needed using the `#[reflect(from_reflect = false)]` attribute. ```rust #[derive(Reflect)] struct Foo; #[derive(Reflect)] #[reflect(from_reflect = false)] struct Bar; fn test<T: FromReflect>(value: T) {} test(Foo); // <-- OK test(Bar); // <-- Panic! Bar does not implement trait `FromReflect` ``` #### `ReflectFromReflect` This PR also automatically adds the `ReflectFromReflect` (introduced in #6245) registration to the derived `GetTypeRegistration` impl— if the type hasn't opted out of `FromReflect` of course. <details> <summary><h4>Improved Deserialization</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. And since we can do all the above, we might as well improve deserialization. We can now choose to deserialize into a Dynamic type or automatically convert it using `FromReflect` under the hood. `[Un]TypedReflectDeserializer::new` will now perform the conversion and return the `Box`'d Real type. `[Un]TypedReflectDeserializer::new_dynamic` will work like what we have now and simply return the `Box`'d Dynamic type. ```rust // Returns the Real type let reflect_deserializer = UntypedReflectDeserializer::new(®istry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // Returns the Dynamic type let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(®istry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` </details> --- ## Changelog * `FromReflect` is now automatically derived within the `Reflect` derive macro * This includes auto-registering `ReflectFromReflect` in the derived `GetTypeRegistration` impl * ~~Renamed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic`, respectively~~ **Descoped** * ~~Changed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to automatically convert the deserialized output using `FromReflect`~~ **Descoped** ## Migration Guide * `FromReflect` is now automatically derived within the `Reflect` derive macro. Items with both derives will need to remove the `FromReflect` one. ```rust // OLD #[derive(Reflect, FromReflect)] struct Foo; // NEW #[derive(Reflect)] struct Foo; ``` If using a manual implementation of `FromReflect` and the `Reflect` derive, users will need to opt-out of the automatic implementation. ```rust // OLD #[derive(Reflect)] struct Foo; impl FromReflect for Foo {/* ... */} // NEW #[derive(Reflect)] #[reflect(from_reflect = false)] struct Foo; impl FromReflect for Foo {/* ... */} ``` <details> <summary><h4>Removed Migrations</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. * The reflect deserializers now perform a `FromReflect` conversion internally. The expected output of `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` is no longer a Dynamic (e.g., `DynamicList`), but its Real counterpart (e.g., `Vec<i32>`). ```rust let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(®istry); let mut deserializer = ron::de::Deserializer::from_str(input)?; // OLD let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // NEW let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` Alternatively, if this behavior isn't desired, use the `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic` methods instead: ```rust // OLD let reflect_deserializer = UntypedReflectDeserializer::new(®istry); // NEW let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(®istry); ``` </details> --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
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Objective
Resolves #4597 (based on the work from #6056 and a refresh of #4147)
When using reflection, we may often end up in a scenario where we have a Dynamic representing a certain type. Unfortunately, we can't just call
MyType::from_reflectas we do not have knowledge of the concrete type (MyType) at runtime.Such scenarios happen when we call
Reflect::clone_value, use the reflection deserializers, or create the Dynamic type ourselves.Solution
Add a
ReflectFromReflecttype data struct.This struct allows us to easily convert Dynamic representations of our types into their respective concrete instances.
Why this PR?
Why now?
The three main reasons I closed #4147 were that:
ReflectFromReflectis clunky (derivingFromReflectand registeringReflectFromReflect)FromReflectHowever, as time has passed it seems 2 and 3 are not really true anymore. Bevy is internally adding lots more
FromReflectderives, which should make this feature all the more useful. Additionally, I have seen a growing number of people look for something likeReflectFromReflect.I think 1 is still an issue, but not a horrible one. Plus it could be made much, much better using #6056. And I think splitting this feature out of #6056 could lead to #6056 being adopted sooner (or at least make the need more clear to users).
Why not just re-open #4147?
The main reason is so that this PR can garner more attention than simply re-opening the old one. This helps bring fresh eyes to the PR for potentially more perspectives/reviews.
Changelog
ReflectFromReflect