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144 Commits

Author SHA1 Message Date
Gino Valente
f5210c54d2
bevy_reflect: Reflection-based cloning (#13432)
# Objective

Using `Reflect::clone_value` can be somewhat confusing to those
unfamiliar with how Bevy's reflection crate works. For example take the
following code:

```rust
let value: usize = 123;
let clone: Box<dyn Reflect> = value.clone_value();
```

What can we expect to be the underlying type of `clone`? If you guessed
`usize`, then you're correct! Let's try another:

```rust
#[derive(Reflect, Clone)]
struct Foo(usize);

let value: Foo = Foo(123);
let clone: Box<dyn Reflect> = value.clone_value();
```

What about this code? What is the underlying type of `clone`? If you
guessed `Foo`, unfortunately you'd be wrong. It's actually
`DynamicStruct`.

It's not obvious that the generated `Reflect` impl actually calls
`Struct::clone_dynamic` under the hood, which always returns
`DynamicStruct`.

There are already some efforts to make this a bit more apparent to the
end-user: #7207 changes the signature of `Reflect::clone_value` to
instead return `Box<dyn PartialReflect>`, signaling that we're
potentially returning a dynamic type.

But why _can't_ we return `Foo`?

`Foo` can obviously be cloned— in fact, we already derived `Clone` on
it. But even without the derive, this seems like something `Reflect`
should be able to handle. Almost all types that implement `Reflect`
either contain no data (trivially clonable), they contain a
`#[reflect_value]` type (which, by definition, must implement `Clone`),
or they contain another `Reflect` type (which recursively fall into one
of these three categories).

This PR aims to enable true reflection-based cloning where you get back
exactly the type that you think you do.

## Solution

Add a `Reflect::reflect_clone` method which returns `Result<Box<dyn
Reflect>, ReflectCloneError>`, where the `Box<dyn Reflect>` is
guaranteed to be the same type as `Self`.

```rust
#[derive(Reflect)]
struct Foo(usize);

let value: Foo = Foo(123);
let clone: Box<dyn Reflect> = value.reflect_clone().unwrap();
assert!(clone.is::<Foo>());
```

Notice that we didn't even need to derive `Clone` for this to work: it's
entirely powered via reflection!

Under the hood, the macro generates something like this:

```rust
fn reflect_clone(&self) -> Result<Box<dyn Reflect>, ReflectCloneError> {
    Ok(Box::new(Self {
        // The `reflect_clone` impl for `usize` just makes use of its `Clone` impl
        0: Reflect::reflect_clone(&self.0)?.take().map_err(/* ... */)?,
    }))
}
```

If we did derive `Clone`, we can tell `Reflect` to rely on that instead:

```rust
#[derive(Reflect, Clone)]
#[reflect(Clone)]
struct Foo(usize);
```

<details>
<summary>Generated Code</summary>

```rust
fn reflect_clone(&self) -> Result<Box<dyn Reflect>, ReflectCloneError> {
    Ok(Box::new(Clone::clone(self)))
}
```

</details>

Or, we can specify our own cloning function:

```rust
#[derive(Reflect)]
#[reflect(Clone(incremental_clone))]
struct Foo(usize);

fn incremental_clone(value: &usize) -> usize {
  *value + 1
}
```

<details>
<summary>Generated Code</summary>

```rust
fn reflect_clone(&self) -> Result<Box<dyn Reflect>, ReflectCloneError> {
    Ok(Box::new(incremental_clone(self)))
}
```

</details>

Similarly, we can specify how fields should be cloned. This is important
for fields that are `#[reflect(ignore)]`'d as we otherwise have no way
to know how they should be cloned.

```rust
#[derive(Reflect)]
struct Foo {
 #[reflect(ignore, clone)]
  bar: usize,
  #[reflect(ignore, clone = "incremental_clone")]
  baz: usize,
}

fn incremental_clone(value: &usize) -> usize {
  *value + 1
}
```

<details>
<summary>Generated Code</summary>

```rust
fn reflect_clone(&self) -> Result<Box<dyn Reflect>, ReflectCloneError> {
    Ok(Box::new(Self {
        bar: Clone::clone(&self.bar),
        baz: incremental_clone(&self.baz),
    }))
}
```

</details>

If we don't supply a `clone` attribute for an ignored field, then the
method will automatically return
`Err(ReflectCloneError::FieldNotClonable {/* ... */})`.

`Err` values "bubble up" to the caller. So if `Foo` contains `Bar` and
the `reflect_clone` method for `Bar` returns `Err`, then the
`reflect_clone` method for `Foo` also returns `Err`.

### Attribute Syntax

You might have noticed the differing syntax between the container
attribute and the field attribute.

This was purely done for consistency with the current attributes. There
are PRs aimed at improving this. #7317 aims at making the
"special-cased" attributes more in line with the field attributes
syntactically. And #9323 aims at moving away from the stringified paths
in favor of just raw function paths.

### Compatibility with Unique Reflect

This PR was designed with Unique Reflect (#7207) in mind. This method
actually wouldn't change that much (if at all) under Unique Reflect. It
would still exist on `Reflect` and it would still `Option<Box<dyn
Reflect>>`. In fact, Unique Reflect would only _improve_ the user's
understanding of what this method returns.

We may consider moving what's currently `Reflect::clone_value` to
`PartialReflect` and possibly renaming it to `partial_reflect_clone` or
`clone_dynamic` to better indicate how it differs from `reflect_clone`.

## Testing

You can test locally by running the following command:

```
cargo test --package bevy_reflect
```

---

## Changelog

- Added `Reflect::reflect_clone` method
- Added `ReflectCloneError` error enum
- Added `#[reflect(Clone)]` container attribute
- Added `#[reflect(clone)]` field attribute
2025-03-11 06:02:59 +00:00
Zachary Harrold
5241e09671
Upgrade to Rust Edition 2024 (#17967)
# Objective

- Fixes #17960

## Solution

- Followed the [edition upgrade
guide](https://doc.rust-lang.org/edition-guide/editions/transitioning-an-existing-project-to-a-new-edition.html)

## Testing

- CI

---

## Summary of Changes

### Documentation Indentation

When using lists in documentation, proper indentation is now linted for.
This means subsequent lines within the same list item must start at the
same indentation level as the item.

```rust
/* Valid */
/// - Item 1
///   Run-on sentence.
/// - Item 2
struct Foo;

/* Invalid */
/// - Item 1
///     Run-on sentence.
/// - Item 2
struct Foo;
```

### Implicit `!` to `()` Conversion

`!` (the never return type, returned by `panic!`, etc.) no longer
implicitly converts to `()`. This is particularly painful for systems
with `todo!` or `panic!` statements, as they will no longer be functions
returning `()` (or `Result<()>`), making them invalid systems for
functions like `add_systems`. The ideal fix would be to accept functions
returning `!` (or rather, _not_ returning), but this is blocked on the
[stabilisation of the `!` type
itself](https://doc.rust-lang.org/std/primitive.never.html), which is
not done.

The "simple" fix would be to add an explicit `-> ()` to system
signatures (e.g., `|| { todo!() }` becomes `|| -> () { todo!() }`).
However, this is _also_ banned, as there is an existing lint which (IMO,
incorrectly) marks this as an unnecessary annotation.

So, the "fix" (read: workaround) is to put these kinds of `|| -> ! { ...
}` closuers into variables and give the variable an explicit type (e.g.,
`fn()`).

```rust
// Valid
let system: fn() = || todo!("Not implemented yet!");
app.add_systems(..., system);

// Invalid
app.add_systems(..., || todo!("Not implemented yet!"));
```

### Temporary Variable Lifetimes

The order in which temporary variables are dropped has changed. The
simple fix here is _usually_ to just assign temporaries to a named
variable before use.

### `gen` is a keyword

We can no longer use the name `gen` as it is reserved for a future
generator syntax. This involved replacing uses of the name `gen` with
`r#gen` (the raw-identifier syntax).

### Formatting has changed

Use statements have had the order of imports changed, causing a
substantial +/-3,000 diff when applied. For now, I have opted-out of
this change by amending `rustfmt.toml`

```toml
style_edition = "2021"
```

This preserves the original formatting for now, reducing the size of
this PR. It would be a simple followup to update this to 2024 and run
`cargo fmt`.

### New `use<>` Opt-Out Syntax

Lifetimes are now implicitly included in RPIT types. There was a handful
of instances where it needed to be added to satisfy the borrow checker,
but there may be more cases where it _should_ be added to avoid
breakages in user code.

### `MyUnitStruct { .. }` is an invalid pattern

Previously, you could match against unit structs (and unit enum
variants) with a `{ .. }` destructuring. This is no longer valid.

### Pretty much every use of `ref` and `mut` are gone

Pattern binding has changed to the point where these terms are largely
unused now. They still serve a purpose, but it is far more niche now.

### `iter::repeat(...).take(...)` is bad

New lint recommends using the more explicit `iter::repeat_n(..., ...)`
instead.

## Migration Guide

The lifetimes of functions using return-position impl-trait (RPIT) are
likely _more_ conservative than they had been previously. If you
encounter lifetime issues with such a function, please create an issue
to investigate the addition of `+ use<...>`.

## Notes

- Check the individual commits for a clearer breakdown for what
_actually_ changed.

---------

Co-authored-by: François Mockers <francois.mockers@vleue.com>
2025-02-24 03:54:47 +00:00
raldone01
1b7db895b7
Harden proc macro path resolution and add integration tests. (#17330)
This pr uses the `extern crate self as` trick to make proc macros behave
the same way inside and outside bevy.

# Objective

- Removes noise introduced by `crate as` in the whole bevy repo.
- Fixes #17004.
- Hardens proc macro path resolution.

## TODO

- [x] `BevyManifest` needs cleanup.
- [x] Cleanup remaining `crate as`.
- [x] Add proper integration tests to the ci.

## Notes

- `cargo-manifest-proc-macros` is written by me and based/inspired by
the old `BevyManifest` implementation and
[`bkchr/proc-macro-crate`](https://github.com/bkchr/proc-macro-crate).
- What do you think about the new integration test machinery I added to
the `ci`?
  More and better integration tests can be added at a later stage.
The goal of these integration tests is to simulate an actual separate
crate that uses bevy. Ideally they would lightly touch all bevy crates.

## Testing

- Needs RA test
- Needs testing from other users
- Others need to run at least `cargo run -p ci integration-test` and
verify that they work.

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
2025-02-09 19:45:45 +00:00
Zachary Harrold
9bc0ae33c3
Move hashbrown and foldhash out of bevy_utils (#17460)
# Objective

- Contributes to #16877

## Solution

- Moved `hashbrown`, `foldhash`, and related types out of `bevy_utils`
and into `bevy_platform_support`
- Refactored the above to match the layout of these types in `std`.
- Updated crates as required.

## Testing

- CI

---

## Migration Guide

- The following items were moved out of `bevy_utils` and into
`bevy_platform_support::hash`:
  - `FixedState`
  - `DefaultHasher`
  - `RandomState`
  - `FixedHasher`
  - `Hashed`
  - `PassHash`
  - `PassHasher`
  - `NoOpHash`
- The following items were moved out of `bevy_utils` and into
`bevy_platform_support::collections`:
  - `HashMap`
  - `HashSet`
- `bevy_utils::hashbrown` has been removed. Instead, import from
`bevy_platform_support::collections` _or_ take a dependency on
`hashbrown` directly.
- `bevy_utils::Entry` has been removed. Instead, import from
`bevy_platform_support::collections::hash_map` or
`bevy_platform_support::collections::hash_set` as appropriate.
- All of the above equally apply to `bevy::utils` and
`bevy::platform_support`.

## Notes

- I left `PreHashMap`, `PreHashMapExt`, and `TypeIdMap` in `bevy_utils`
as they might be candidates for micro-crating. They can always be moved
into `bevy_platform_support` at a later date if desired.
2025-01-23 16:46:08 +00:00
MichiRecRoom
26bb0b40d2
Move #![warn(clippy::allow_attributes, clippy::allow_attributes_without_reason)] to the workspace Cargo.toml (#17374)
# Objective
Fixes https://github.com/bevyengine/bevy/issues/17111

## Solution
Move `#![warn(clippy::allow_attributes,
clippy::allow_attributes_without_reason)]` to the workspace `Cargo.toml`

## Testing
Lots of CI testing, and local testing too.

---------

Co-authored-by: Benjamin Brienen <benjamin.brienen@outlook.com>
2025-01-15 01:14:58 +00:00
MichiRecRoom
447108b2a4
Downgrade clippy::allow_attributes and clippy::allow_attributes_without_reason to warn (#17320)
# Objective
I realized that setting these to `deny` may have been a little
aggressive - especially since we upgrade warnings to denies in CI.

## Solution
Downgrades these lints to `warn`, so that compiles can work locally. CI
will still treat these as denies.
2025-01-12 05:28:26 +00:00
MichiRecRoom
5f5876b1c9
Change bevy_reflect::RegisterForReflection::__register() to expect unused variables, rather than putting underscores on the parameter names (#17171)
# Objective
While checking over https://github.com/bevyengine/bevy/pull/17160, it
occurred to me that rust-analyzer will copy the method signature
exactly, when using tab completion trait methods. This includes provided
trait methods that use underscores to silence the `unused_variables`
lint. This probably isn't good for users, seeing as how they'll have to
remove the underscore if they want to use the parameters.

(I mean, they technically don't have to remove the underscore... but
usually you don't keep a leading underscore on parameters you're using.)

## Solution
Changes `bevy_reflect::RegisterForReflection::__register()` to
`#[expect(unused_variables)]`, and removes the underscores from its
parameter names.

## Testing
N/A
2025-01-05 20:27:20 +00:00
MichiRecRoom
120b733ab5
bevy_reflect: Apply #[deny(clippy::allow_attributes, clippy::allow_attributes_without_reason)] (#17092)
# Objective
We want to deny the following lints:
* `clippy::allow_attributes` - Because there's no reason to
`#[allow(...)]` an attribute if it wouldn't lint against anything; you
should always use `#[expect(...)]`
* `clippy::allow_attributes_without_reason` - Because documenting the
reason for allowing/expecting a lint is always good

## Solution
Set the `clippy::allow_attributes` and
`clippy::allow_attributes_without_reason` lints to `deny`, and bring
`bevy_reflect` in line with the new restrictions.

No code changes have been made - except if a lint that was previously
`allow(...)`'d could be removed via small code changes. For example,
`unused_variables` can be handled by adding a `_` to the beginning of a
field's name.

## Testing
I ran `cargo clippy`, and received no errors.
2025-01-03 22:22:34 +00:00
Zachary Harrold
0403948aa2
Remove Implicit std Prelude from no_std Crates (#17086)
# Background

In `no_std` compatible crates, there is often an `std` feature which
will allow access to the standard library. Currently, with the `std`
feature _enabled_, the
[`std::prelude`](https://doc.rust-lang.org/std/prelude/index.html) is
implicitly imported in all modules. With the feature _disabled_, instead
the [`core::prelude`](https://doc.rust-lang.org/core/prelude/index.html)
is implicitly imported. This creates a subtle and pervasive issue where
`alloc` items _may_ be implicitly included (if `std` is enabled), or
must be explicitly included (if `std` is not enabled).

# Objective

- Make the implicit imports for `no_std` crates consistent regardless of
what features are/not enabled.

## Solution

- Replace the `cfg_attr` "double negative" `no_std` attribute with
conditional compilation to _include_ `std` as an external crate.
```rust
// Before
#![cfg_attr(not(feature = "std"), no_std)]

// After
#![no_std]

#[cfg(feature = "std")]
extern crate std;
```
- Fix imports that are currently broken but are only now visible with
the above fix.

## Testing

- CI

## Notes

I had previously used the "double negative" version of `no_std` based on
general consensus that it was "cleaner" within the Rust embedded
community. However, this implicit prelude issue likely was considered
when forming this consensus. I believe the reason why is the items most
affected by this issue are provided by the `alloc` crate, which is
rarely used within embedded but extensively used within Bevy.
2025-01-03 01:58:43 +00:00
Rich Churcher
f2719f5470
Rust 1.83, allow -> expect (missing_docs) (#16561)
# Objective

We were waiting for 1.83 to address most of these, due to a bug with
`missing_docs` and `expect`. Relates to, but does not entirely complete,
#15059.

## Solution

- Upgrade to 1.83
- Switch `allow(missing_docs)` to `expect(missing_docs)`
- Remove a few now-unused `allow`s along the way, or convert to `expect`
2024-12-16 23:27:57 +00:00
Clar Fon
711246aa34
Update hashbrown to 0.15 (#15801)
Updating dependencies; adopted version of #15696. (Supercedes #15696.)

Long answer: hashbrown is no longer using ahash by default, meaning that
we can't use the default-hasher methods with ahasher. So, we have to use
the longer-winded versions instead. This takes the opportunity to also
switch our default hasher as well, but without actually enabling the
default-hasher feature for hashbrown, meaning that we'll be able to
change our hasher more easily at the cost of all of these method calls
being obnoxious forever.

One large change from 0.15 is that `insert_unique_unchecked` is now
`unsafe`, and for cases where unsafe code was denied at the crate level,
I replaced it with `insert`.

## Migration Guide

`bevy_utils` has updated its version of `hashbrown` to 0.15 and now
defaults to `foldhash` instead of `ahash`. This means that if you've
hard-coded your hasher to `bevy_utils::AHasher` or separately used the
`ahash` crate in your code, you may need to switch to `foldhash` to
ensure that everything works like it does in Bevy.
2024-12-10 19:45:50 +00:00
Zachary Harrold
bf765e61b5
Add no_std support to bevy_reflect (#16256)
# Objective

- Contributes to #15460

## Solution

- Added `std` feature (enabled by default)

## Testing

- CI
- `cargo check -p bevy_reflect --no-default-features --target
"x86_64-unknown-none"`
- UEFI demo application runs with this branch of `bevy_reflect`,
allowing `derive(Reflect)`

## Notes

- The [`spin`](https://crates.io/crates/spin) crate has been included to
provide `RwLock` and `Once` (as an alternative to `OnceLock`) when the
`std` feature is not enabled. Another alternative may be more desirable,
please provide feedback if you have a strong opinion here!
- Certain items (`Box`, `String`, `ToString`) provided by `alloc` have
been added to `__macro_exports` as a way to avoid `alloc` vs `std`
namespacing. I'm personally quite annoyed that we can't rely on `alloc`
as a crate name in `std` environments within macros. I'd love an
alternative to my approach here, but I suspect it's the least-bad
option.
- I would've liked to have an `alloc` feature (for allocation-free
`bevy_reflect`), unfortunately, `erased_serde` unconditionally requires
access to `Box`. Maybe one day we could design around this, but for now
it just means `bevy_reflect` requires `alloc`.

---------

Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
2024-12-05 21:15:21 +00:00
Arnav Mummineni
39842170a5
Update example link (#16581)
# Objective

Redirects broken example link to point to the most similar alternative
2024-12-01 09:47:22 +00:00
Rob Parrett
30d84519a2
Use en-us locale for typos (#16037)
# Objective

Bevy seems to want to standardize on "American English" spellings. Not
sure if this is laid out anywhere in writing, but see also #15947.

While perusing the docs for `typos`, I noticed that it has a `locale`
config option and tried it out.

## Solution

Switch to `en-us` locale in the `typos` config and run `typos -w`

## Migration Guide

The following methods or fields have been renamed from `*dependants*` to
`*dependents*`.

- `ProcessorAssetInfo::dependants`
- `ProcessorAssetInfos::add_dependant`
- `ProcessorAssetInfos::non_existent_dependants`
- `AssetInfo::dependants_waiting_on_load`
- `AssetInfo::dependants_waiting_on_recursive_dep_load`
- `AssetInfos::loader_dependants`
- `AssetInfos::remove_dependants_and_labels`
2024-10-20 18:55:17 +00:00
Torstein Grindvik
9f5f5d3d41
bevy_reflect: get_represented_kind_info APIs for reflected kinds (#14380)
# Objective

Fixes #14378

---------

Signed-off-by: Torstein Grindvik <torstein.grindvik@muybridge.com>
Co-authored-by: Torstein Grindvik <torstein.grindvik@muybridge.com>
Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
2024-10-15 02:08:31 +00:00
Nathan Lilienthal
0b2e0cfaca
bevy_reflect: Add crate level functions feature docs (#15086)
Adds the missing section for the `functions` cargo feature of the
`bevy_reflect` crate.
2024-10-09 18:06:56 +00:00
Benjamin Brienen
c841dd92a1
Documentation for variadics (#15387)
# Objective

Relevant: #15208

## Solution

I went ahead and added the variadics documentation in all applicable
locations.

## Testing

- I built the documentation and inspected it to see whether the feature
is there.
2024-10-02 12:48:36 +00:00
Gino Valente
397f20e835
bevy_reflect: Generic parameter info (#15475)
# Objective

Currently, reflecting a generic type provides no information about the
generic parameters. This means that you can't get access to the type of
`T` in `Foo<T>` without creating custom type data (we do this for
[`ReflectHandle`](https://docs.rs/bevy/0.14.2/bevy/asset/struct.ReflectHandle.html#method.asset_type_id)).

## Solution

This PR makes it so that generic type parameters and generic const
parameters are tracked in a `Generics` struct stored on the `TypeInfo`
for a type.

For example, `struct Foo<T, const N: usize>` will store `T` and `N` as a
`TypeParamInfo` and `ConstParamInfo`, respectively.

The stored information includes:

- The name of the generic parameter (i.e. `T`, `N`, etc.)
- The type of the generic parameter (remember that we're dealing with
monomorphized types, so this will actually be a concrete type)
- The default type/value, if any (e.g. `f32` in `T = f32` or `10` in
`const N: usize = 10`)

### Caveats

The only requirement for this to work is that the user does not opt-out
of the automatic `TypePath` derive with `#[reflect(type_path = false)]`.

Doing so prevents the macro code from 100% knowing that the generic type
implements `TypePath`. This in turn means the generated `Typed` impl
can't add generics to the type.

There are two solutions for this—both of which I think we should explore
in a future PR:

1. We could just not use `TypePath`. This would mean that we can't store
the `Type` of the generic, but we can at least store the `TypeId`.
2. We could provide a way to opt out of the automatic `Typed` derive
with a `#[reflect(typed = false)]` attribute. This would allow users to
manually implement `Typed` to add whatever generic information they need
(e.g. skipping a parameter that can't implement `TypePath` while the
rest can).

I originally thought about making `Generics` an enum with `Generic`,
`NonGeneric`, and `Unavailable` variants to signify whether there are
generics, no generics, or generics that cannot be added due to opting
out of `TypePath`. I ultimately decided against this as I think it adds
a bit too much complexity for such an uncommon problem.

Additionally, user's don't necessarily _have_ to know the generics of a
type, so just skipping them should generally be fine for now.

## Testing

You can test locally by running:

```
cargo test --package bevy_reflect
```

---

## Showcase

You can now access generic parameters via `TypeInfo`!

```rust
#[derive(Reflect)]
struct MyStruct<T, const N: usize>([T; N]);

let generics = MyStruct::<f32, 10>::type_info().generics();

// Get by index:
let t = generics.get(0).unwrap();
assert_eq!(t.name(), "T");
assert!(t.ty().is::<f32>());
assert!(!t.is_const());

// Or by name:
let n = generics.get_named("N").unwrap();
assert_eq!(n.name(), "N");
assert!(n.ty().is::<usize>());
assert!(n.is_const());
```

You can even access parameter defaults:

```rust
#[derive(Reflect)]
struct MyStruct<T = String, const N: usize = 10>([T; N]);

let generics = MyStruct::<f32, 5>::type_info().generics();

let GenericInfo::Type(info) = generics.get_named("T").unwrap() else {
    panic!("expected a type parameter");
};

let default = info.default().unwrap();

assert!(default.is::<String>());

let GenericInfo::Const(info) = generics.get_named("N").unwrap() else {
    panic!("expected a const parameter");
};

let default = info.default().unwrap();

assert_eq!(default.downcast_ref::<usize>().unwrap(), &10);
```
2024-09-30 17:58:37 +00:00
andriyDev
04d5685889
Make drain take a mutable borrow instead of Box<Self> for reflected Map, List, and Set. (#15406)
# Objective

Fixes #15185.

# Solution

Change `drain` to take a `&mut self` for most reflected types.

Some notable exceptions to this change are `Array` and `Tuple`. These
types don't make sense with `drain` taking a mutable borrow since they
can't get "smaller". Also `BTreeMap` doesn't have a `drain` function, so
we have to pop elements off one at a time.

## Testing

- The existing tests are sufficient.

---

## Migration Guide

- `reflect::Map`, `reflect::List`, and `reflect::Set` all now take a
`&mut self` instead of a `Box<Self>`. Callers of these traits should add
`&mut` before their boxes, and implementers of these traits should
update to match.
2024-09-30 17:19:13 +00:00
Zachary Harrold
d70595b667
Add core and alloc over std Lints (#15281)
# Objective

- Fixes #6370
- Closes #6581

## Solution

- Added the following lints to the workspace:
  - `std_instead_of_core`
  - `std_instead_of_alloc`
  - `alloc_instead_of_core`
- Used `cargo +nightly fmt` with [item level use
formatting](https://rust-lang.github.io/rustfmt/?version=v1.6.0&search=#Item%5C%3A)
to split all `use` statements into single items.
- Used `cargo clippy --workspace --all-targets --all-features --fix
--allow-dirty` to _attempt_ to resolve the new linting issues, and
intervened where the lint was unable to resolve the issue automatically
(usually due to needing an `extern crate alloc;` statement in a crate
root).
- Manually removed certain uses of `std` where negative feature gating
prevented `--all-features` from finding the offending uses.
- Used `cargo +nightly fmt` with [crate level use
formatting](https://rust-lang.github.io/rustfmt/?version=v1.6.0&search=#Crate%5C%3A)
to re-merge all `use` statements matching Bevy's previous styling.
- Manually fixed cases where the `fmt` tool could not re-merge `use`
statements due to conditional compilation attributes.

## Testing

- Ran CI locally

## Migration Guide

The MSRV is now 1.81. Please update to this version or higher.

## Notes

- This is a _massive_ change to try and push through, which is why I've
outlined the semi-automatic steps I used to create this PR, in case this
fails and someone else tries again in the future.
- Making this change has no impact on user code, but does mean Bevy
contributors will be warned to use `core` and `alloc` instead of `std`
where possible.
- This lint is a critical first step towards investigating `no_std`
options for Bevy.

---------

Co-authored-by: François Mockers <francois.mockers@vleue.com>
2024-09-27 00:59:59 +00:00
Clar Fon
efda7f3f9c
Simpler lint fixes: makes ci lints work but disables a lint for now (#15376)
Takes the first two commits from #15375 and adds suggestions from this
comment:
https://github.com/bevyengine/bevy/pull/15375#issuecomment-2366968300

See #15375 for more reasoning/motivation.

## Rebasing (rerunning)

```rust
git switch simpler-lint-fixes
git reset --hard main
cargo fmt --all -- --unstable-features --config normalize_comments=true,imports_granularity=Crate
cargo fmt --all
git add --update
git commit --message "rustfmt"
cargo clippy --workspace --all-targets --all-features --fix
cargo fmt --all -- --unstable-features --config normalize_comments=true,imports_granularity=Crate
cargo fmt --all
git add --update
git commit --message "clippy"
git cherry-pick e6c0b94f6795222310fb812fa5c4512661fc7887
```
2024-09-24 11:42:59 +00:00
Gino Valente
83356b12c9
bevy_reflect: Replace "value" terminology with "opaque" (#15240)
# Objective

Currently, the term "value" in the context of reflection is a bit
overloaded.

For one, it can be used synonymously with "data" or "variable". An
example sentence would be "this function takes a reflected value".

However, it is also used to refer to reflected types which are
`ReflectKind::Value`. These types are usually either primitives, opaque
types, or types that don't fall into any other `ReflectKind` (or perhaps
could, but don't due to some limitation/difficulty). An example sentence
would be "this function takes a reflected value type".

This makes it difficult to write good documentation or other learning
material without causing some amount of confusion to readers. Ideally,
we'd be able to move away from the `ReflectKind::Value` usage and come
up with a better term.

## Solution

This PR replaces the terminology of "value" with "opaque" across
`bevy_reflect`. This includes in documentation, type names, variant
names, and macros.

The term "opaque" was chosen because that's essentially how the type is
treated within the reflection API. In other words, its internal
structure is hidden. All we can do is work with the type itself.

### Primitives

While primitives are not technically opaque types, I think it's still
clearer to refer to them as "opaque" rather than keep the confusing
"value" terminology.

We could consider adding another concept for primitives (e.g.
`ReflectKind::Primitive`), but I'm not sure that provides a lot of
benefit right now. In most circumstances, they'll be treated just like
an opaque type. They would also likely use the same macro (or two copies
of the same macro but with different names).

## Testing

You can test locally by running:

```
cargo test --package bevy_reflect --all-features
```

---

## Migration Guide

The reflection concept of "value type" has been replaced with a clearer
"opaque type". The following renames have been made to account for this:

- `ReflectKind::Value` → `ReflectKind::Opaque`
- `ReflectRef::Value` → `ReflectRef::Opaque`
- `ReflectMut::Value` → `ReflectMut::Opaque`
- `ReflectOwned::Value` → `ReflectOwned::Opaque`
- `TypeInfo::Value` → `TypeInfo::Opaque`
- `ValueInfo` → `OpaqueInfo`
- `impl_reflect_value!` → `impl_reflect_opaque!`
- `impl_from_reflect_value!` → `impl_from_reflect_opaque!`

Additionally, declaring your own opaque types no longer uses
`#[reflect_value]`. This attribute has been replaced by
`#[reflect(opaque)]`:

```rust
// BEFORE
#[derive(Reflect)]
#[reflect_value(Default)]
struct MyOpaqueType(u32);

// AFTER
#[derive(Reflect)]
#[reflect(opaque)]
#[reflect(Default)]
struct MyOpaqueType(u32);
```

Note that the order in which `#[reflect(opaque)]` appears does not
matter.
2024-09-23 18:04:57 +00:00
Benjamin Brienen
8a6d0b063c
Use crate: disqualified (#15372)
# Objective

Fixes #15351 

## Solution

- Created new external crate and ported over the code

## Testing

- CI

## Migration guide

Replace references to `bevy_utils::ShortName` with
`disqualified::ShortName`.
2024-09-23 17:34:17 +00:00
Clar Fon
2c5be2ef4c
Reflect for TextureFormat (#15355)
# Objective

In order to derive `Reflect`, all of a struct's fields must implement
`FromReflect`. [As part of looking into some of the work mentioned
here](https://github.com/bevyengine/bevy/issues/13713#issuecomment-2364786694),
I noticed that `TextureFormat` doesn't implement `Reflect`, and decided
to split that into a separate PR.

## Solution

I decided that `TextureFormat` should be a `reflect_value` since,
although one variant has fields, most users will treat this as an opaque
value set explicitly. It also substantially reduces the complexity of
the implementation.

For now, this implementation isn't actually used by any crates, so, I
decided to not preemptively enable the feature on anything. But it's
technically an option, now, and more `wgpu` types can be added in the
future.

## Testing

Everything compiles okay, and I can't really see how this could be done
incorrectly given the above constraints.
2024-09-23 17:26:12 +00:00
Gino Valente
4d0961cc8a
bevy_reflect: Add ReflectRef/ReflectMut/ReflectOwned convenience casting methods (#15235)
# Objective

#13320 added convenience methods for casting a `TypeInfo` into its
respective variant:

```rust
let info: &TypeInfo = <Vec<i32> as Typed>::type_info();

// We know `info` contains a `ListInfo`, so we can simply cast it:
let list_info: &ListInfo = info.as_list().unwrap();
```

This is especially helpful when you have already verified a type is a
certain kind via `ReflectRef`, `ReflectMut`, `ReflectOwned`, or
`ReflectKind`.

As mentioned in that PR, though, it would be useful to add similar
convenience methods to those types as well.

## Solution

Added convenience casting methods to `ReflectRef`, `ReflectMut`, and
`ReflectOwned`.

With these methods, I was able to reduce our nesting in certain places
throughout the crate.

Additionally, I took this opportunity to move these types (and
`ReflectKind`) to their own module to help clean up the `reflect`
module.

## Testing

You can test locally by running:

```
cargo test --package bevy_reflect --all-features
```

---

## Showcase

Convenience methods for casting `ReflectRef`, `ReflectMut`, and
`ReflectOwned` into their respective variants has been added! This
allows you to write cleaner code if you already know the kind of your
reflected data:

```rust
// BEFORE
let ReflectRef::List(list) = list.reflect_ref() else {
    panic!("expected list");
};

// AFTER
let list = list.reflect_ref().as_list().unwrap();
```

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Pablo Reinhardt <126117294+pablo-lua@users.noreply.github.com>
2024-09-23 16:50:46 +00:00
Gino Valente
59c0521690
bevy_reflect: Add Function trait (#15205)
# Objective

While #13152 added function reflection, it didn't really make functions
reflectable. Instead, it made it so that they can be called with
reflected arguments and return reflected data. But functions themselves
cannot be reflected.

In other words, we can't go from `DynamicFunction` to `dyn
PartialReflect`.

## Solution

Allow `DynamicFunction` to actually be reflected.

This PR adds the `Function` reflection subtrait (and corresponding
`ReflectRef`, `ReflectKind`, etc.). With this new trait, we're able to
implement `PartialReflect` on `DynamicFunction`.

### Implementors

`Function` is currently only implemented for `DynamicFunction<'static>`.
This is because we can't implement it generically over all
functions—even those that implement `IntoFunction`.

What about `DynamicFunctionMut`? Well, this PR does **not** implement
`Function` for `DynamicFunctionMut`.

The reasons for this are a little complicated, but it boils down to
mutability. `DynamicFunctionMut` requires `&mut self` to be invoked
since it wraps a `FnMut`. However, we can't really model this well with
`Function`. And if we make `DynamicFunctionMut` wrap its internal
`FnMut` in a `Mutex` to allow for `&self` invocations, then we run into
either concurrency issues or recursion issues (or, in the worst case,
both).

So for the time-being, we won't implement `Function` for
`DynamicFunctionMut`. It will be better to evaluate it on its own. And
we may even consider the possibility of removing it altogether if it
adds too much complexity to the crate.

### Dynamic vs Concrete

One of the issues with `DynamicFunction` is the fact that it's both a
dynamic representation (like `DynamicStruct` or `DynamicList`) and the
only way to represent a function.

Because of this, it's in a weird middle ground where we can't easily
implement full-on `Reflect`. That would require `Typed`, but what static
`TypeInfo` could it provide? Just that it's a `DynamicFunction`? None of
the other dynamic types implement `Typed`.

However, by not implementing `Reflect`, we lose the ability to downcast
back to our `DynamicStruct`. Our only option is to call
`Function::clone_dynamic`, which clones the data rather than by simply
downcasting. This works in favor of the `PartialReflect::try_apply`
implementation since it would have to clone anyways, but is definitely
not ideal. This is also the reason I had to add `Debug` as a supertrait
on `Function`.

For now, this PR chooses not to implement `Reflect` for
`DynamicFunction`. We may want to explore this in a followup PR (or even
this one if people feel strongly that it's strictly required).

The same is true for `FromReflect`. We may decide to add an
implementation there as well, but it's likely out-of-scope of this PR.

## Testing

You can test locally by running:

```
cargo test --package bevy_reflect --all-features
```

---

## Showcase

You can now pass around a `DynamicFunction` as a `dyn PartialReflect`!
This also means you can use it as a field on a reflected type without
having to ignore it (though you do need to opt out of `FromReflect`).

```rust
#[derive(Reflect)]
#[reflect(from_reflect = false)]
struct ClickEvent {
    callback: DynamicFunction<'static>,
}

let event: Box<dyn Struct> = Box::new(ClickEvent {
    callback: (|| println!("Clicked!")).into_function(),
});

// We can access our `DynamicFunction` as a `dyn PartialReflect`
let callback: &dyn PartialReflect = event.field("callback").unwrap();

// And access function-related methods via the new `Function` trait
let ReflectRef::Function(callback) = callback.reflect_ref() else {
    unreachable!()
};

// Including calling the function
callback.reflect_call(ArgList::new()).unwrap(); // Prints: Clicked!
```
2024-09-22 14:19:12 +00:00
Benjamin Brienen
02a9ed4b0b
move ShortName to bevy_reflect (#15340)
# Objective

- Goal is to minimize bevy_utils #11478

## Solution

- Move the file short_name wholesale into bevy_reflect

## Testing

- Unit tests
- CI

## Migration Guide

- References to `bevy_utils::ShortName` should instead now be
`bevy_reflect::ShortName`.

---------

Co-authored-by: François Mockers <francois.mockers@vleue.com>
2024-09-21 20:52:46 +00:00
Rich Churcher
fd329c0426
Allow to expect (adopted) (#15301)
# Objective

> Rust 1.81 released the #[expect(...)] attribute, which works like
#[allow(...)] but throws a warning if the lint isn't raised. This is
preferred to #[allow(...)] because it tells us when it can be removed.

- Adopts the parts of #15118 that are complete, and updates the branch
so it can be merged.
- There were a few conflicts, let me know if I misjudged any of 'em.

Alice's
[recommendation](https://github.com/bevyengine/bevy/issues/15059#issuecomment-2349263900)
seems well-taken, let's do this crate by crate now that @BD103 has done
the lion's share of this!

(Relates to, but doesn't yet completely finish #15059.)

Crates this _doesn't_ cover:

- bevy_input
- bevy_gilrs
- bevy_window
- bevy_winit
- bevy_state
- bevy_render
- bevy_picking
- bevy_core_pipeline
- bevy_sprite
- bevy_text
- bevy_pbr
- bevy_ui
- bevy_gltf
- bevy_gizmos
- bevy_dev_tools
- bevy_internal
- bevy_dylib

---------

Co-authored-by: BD103 <59022059+BD103@users.noreply.github.com>
Co-authored-by: Ben Frankel <ben.frankel7@gmail.com>
Co-authored-by: Antony <antony.m.3012@gmail.com>
2024-09-20 19:16:42 +00:00
Zachary Harrold
fcfa60844a
Remove allocation in get_short_name (#15294)
`ShortName` is lazily evaluated and does not allocate, instead providing
`Display` and `Debug` implementations which write directly to a
formatter using the original algorithm. When using `ShortName` in format
strings (`panic`, `dbg`, `format`, etc.) you can directly use the
`ShortName` type. If you require a `String`, simply call
`ShortName(...).to_string()`.

# Objective

- Remove the requirement for allocation when using `get_short_name`

## Solution

- Added new type `ShortName` which wraps a name and provides its own
`Debug` and `Display` implementations, using the original
`get_short_name` algorithm without the need for allocating.
- Removed `get_short_name`, as `ShortName(...)` is more performant and
ergonomic.
- Added `ShortName::of::<T>` method to streamline the common use-case
for name shortening.

## Testing

- CI

## Migration Guide

### For `format!`, `dbg!`, `panic!`, etc.

```rust
// Before
panic!("{} is too short!", get_short_name(name));

// After
panic!("{} is too short!", ShortName(name));
```

### Need a `String` Value

```rust
// Before
let short: String = get_short_name(name);

// After
let short: String = ShortName(name).to_string();
```

## Notes

`ShortName` lazily evaluates, and directly writes to a formatter via
`Debug` and `Display`, which removes the need to allocate a `String`
when printing a shortened type name. Because the implementation has been
moved into the `fmt` method, repeated printing of the `ShortName` type
may be less performant than converting it into a `String`. However, no
instances of this are present in Bevy, and the user can get the original
behaviour by calling `.to_string()` at no extra cost.

---------

Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2024-09-19 15:34:03 +00:00
Gino Valente
69541462c5
bevy_reflect: Add Reflectable trait (#5772)
# Objective

When deriving `Reflect`, users will notice that their generic arguments
also need to implement `Reflect`:

```rust
#[derive(Reflect)]
struct Foo<T: Reflect> {
  value: T
}
```

This works well for now. However, as we want to do more with `Reflect`,
these bounds might need to change. For example, to get #4154 working, we
likely need to enforce the `GetTypeRegistration` trait. So now we have:

```rust
#[derive(Reflect)]
struct Foo<T: Reflect + GetTypeRegistration> {
  value: T
}
```

Not great, but not horrible. However, we might then want to do something
as suggested in
[this](https://github.com/bevyengine/bevy/issues/5745#issuecomment-1221389131)
comment and add a `ReflectTypeName` trait for stable type name support.
Well now we have:

```rust
#[derive(Reflect)]
struct Foo<T: Reflect + GetTypeRegistration + ReflectTypeName> {
  value: T
}
```

Now imagine that for even two or three generic types. Yikes!

As the API changes it would be nice if users didn't need to manually
migrate their generic type bounds like this.

A lot of these traits are (or will/might be) core to the entire
reflection API. And although `Reflect` can't add them as supertraits for
object-safety reasons, they are still indirectly required for things to
function properly (manual implementors will know how easy it is to
forget to implement `GetTypeRegistration`). And they should all be
automatically implemented for user types anyways as long they're using
`#[derive(Reflect)]`.

## Solution

Add a "catch-all" trait called `Reflectable` whose supertraits are a
select handful of core reflection traits.

This allows us to consolidate all the examples above into this:

```rust
#[derive(Reflect)]
struct Foo<T: Reflectable> {
  value: T
}
```

And as we experiment with the API, users can rest easy knowing they
don't need to migrate dozens upon dozens of types. It should all be
automatic!

## Discussion

1. Thoughts on the name `Reflectable`? Is it too easily confused with
`Reflect`? Or does it at least accurately describe that this contains
the core traits? If not, maybe `BaseReflect`?

---

## Changelog

- Added the `Reflectable` trait

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
2024-09-18 00:36:41 +00:00
Al M.
2ea51fc60f
Use FromReflect when extracting entities in dynamic scenes (#15174)
# Objective

Fix #10284.

## Solution

When `DynamicSceneBuilder` extracts entities, they are cloned via
`PartialReflect::clone_value`, making them into dynamic versions of the
original components. This loses any custom `ReflectSerialize` type data.
Dynamic scenes are deserialized with the original types, not the dynamic
versions, and so any component with a custom serialize may fail. In this
case `Rect` and `Vec2`. The dynamic version includes the field names 'x'
and 'y' but the `Serialize` impl doesn't, hence the "expect float"
error.

The solution here: Instead of using `clone_value` to clone the
components, `FromReflect` clones and retains the original information
needed to serialize with any custom `Serialize` impls. I think using
something like `reflect_clone` from
(https://github.com/bevyengine/bevy/pull/13432) might make this more
efficient.

I also did the same when deserializing dynamic scenes to appease some of
the round-trip tests which use `ReflectPartialEq`, which requires the
types be the same and not a unique/proxy pair. I'm not sure it's
otherwise necessary. Maybe this would also be more efficient when
spawning dynamic scenes with `reflect_clone` instead of `FromReflect`
again?

An alternative solution would be to fall back to the dynamic version
when deserializing `DynamicScene`s if the custom version fails. I think
that's possible. Or maybe simply always deserializing via the dynamic
route for dynamic scenes?

## Testing

This example is similar to the original test case in #10284:

``` rust
#![allow(missing_docs)]

use bevy::{prelude::*, scene::SceneInstanceReady};

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_systems(Startup, (save, load).chain())
        .observe(check)
        .run();
}

static SAVEGAME_SAVE_PATH: &str = "savegame.scn.ron";

fn save(world: &mut World) {
    let entity = world.spawn(OrthographicProjection::default()).id();

    let scene = DynamicSceneBuilder::from_world(world)
        .extract_entity(entity)
        .build();

    if let Some(registry) = world.get_resource::<AppTypeRegistry>() {
        let registry = registry.read();
        let serialized_scene = scene.serialize(&registry).unwrap();
        // println!("{}", serialized_scene);
        std::fs::write(format!("assets/{SAVEGAME_SAVE_PATH}"), serialized_scene).unwrap();
    }

    world.entity_mut(entity).despawn_recursive();
}

fn load(mut commands: Commands, asset_server: Res<AssetServer>) {
    commands.spawn(DynamicSceneBundle {
        scene: asset_server.load(SAVEGAME_SAVE_PATH),
        ..default()
    });
}

fn check(_trigger: Trigger<SceneInstanceReady>, query: Query<&OrthographicProjection>) {
    dbg!(query.single());
}
```


## Migration Guide

The `DynamicScene` format is changed to use custom serialize impls so
old scene files will need updating:

Old: 

```ron
(
  resources: {},
  entities: {
    4294967299: (
      components: {
        "bevy_render:📷:projection::OrthographicProjection": (
          near: 0.0,
          far: 1000.0,
          viewport_origin: (
            x: 0.5,
            y: 0.5,
          ),
          scaling_mode: WindowSize(1.0),
          scale: 1.0,
          area: (
            min: (
              x: -1.0,
              y: -1.0,
            ),
            max: (
              x: 1.0,
              y: 1.0,
            ),
          ),
        ),
      },
    ),
  },
)
```

New:

```ron
(
  resources: {},
  entities: {
    4294967299: (
      components: {
        "bevy_render:📷:projection::OrthographicProjection": (
          near: 0.0,
          far: 1000.0,
          viewport_origin: (0.5, 0.5),
          scaling_mode: WindowSize(1.0),
          scale: 1.0,
          area: (
            min: (-1.0, -1.0),
            max: (1.0, 1.0),
          ),
        ),
      },
    ),
  },
)
```

---------

Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2024-09-15 14:33:39 +00:00
Gino Valente
37443e0f3f
bevy_reflect: Add DynamicTyped trait (#15108)
# Objective

Thanks to #7207, we now have a way to validate at the type-level that a
reflected value is actually the type it says it is and not just a
dynamic representation of that type.

`dyn PartialReflect` values _might_ be a dynamic type, but `dyn Reflect`
values are guaranteed to _not_ be a dynamic type.

Therefore, we can start to add methods to `Reflect` that weren't really
possible before. For example, we should now be able to always get a
`&'static TypeInfo`, and not just an `Option<&'static TypeInfo>`.

## Solution

Add the `DynamicTyped` trait.

This trait is similar to `DynamicTypePath` in that it provides a way to
use the non-object-safe `Typed` trait in an object-safe way.

And since all types that derive `Reflect` will also derive `Typed`, we
can safely add `DynamicTyped` as a supertrait of `Reflect`. This allows
us to use it when just given a `dyn Reflect` trait object.

## Testing

You can test locally by running:

```
cargo test --package bevy_reflect
```

---

## Showcase

`Reflect` now has a supertrait of `DynamicTyped`, allowing `TypeInfo` to
be retrieved from a `dyn Reflect` trait object without having to unwrap
anything!

```rust
let value: Box<dyn Reflect> = Box::new(String::from("Hello!"));

// BEFORE
let info: &'static TypeInfo = value.get_represented_type_info().unwrap();

// AFTER
let info: &'static TypeInfo = value.reflect_type_info();
```

## Migration Guide

`Reflect` now has a supertrait of `DynamicTyped`. If you were manually
implementing `Reflect` and did not implement `Typed`, you will now need
to do so.
2024-09-13 17:17:10 +00:00
Gino Valente
90bb1adeb2
bevy_reflect: Contextual serialization error messages (#13888)
# Objective

Reflection serialization can be difficult to debug. A lot of times a
type fails to be serialized and the user is left wondering where that
type came from.

This is most often encountered with Bevy's scenes. Attempting to
serialize all resources in the world will fail because some resources
can't be serialized.

For example, users will often get complaints about `bevy_utils::Instant`
not registering `ReflectSerialize`. Well, `Instant` can't be serialized,
so the only other option is to exclude the resource that contains it.
But what resource contains it? This is where reflection serialization
can get a little tricky (it's `Time<Real>` btw).

## Solution

Add the `debug_stack` feature to `bevy_reflect`. When enabled, the
reflection serializers and deserializers will keep track of the current
type stack. And this stack will be used in error messages to help with
debugging.

Now, if we unknowingly try to serialize `Time<Real>`, we'll get the
following error:

```
type `bevy_utils::Instant` did not register the `ReflectSerialize` type data. For certain types, this may need to be registered manually using `register_type_data` (stack: `bevy_time::time::Time<bevy_time::real::Real>` -> `bevy_time::real::Real` -> `bevy_utils::Instant`)
```

### Implementation

This makes use of `thread_local!` to manage an internal `TypeInfoStack`
which holds a stack of `&'static TypeInfo`. We push to the stack before
a type is (de)serialized and pop from the stack afterwards.

Using a thread-local should be fine since we know two (de)serializers
can't be running at the same time (and if they're running on separate
threads, then we're still good).

The only potential issue would be if a user went through one of the
sub-serializers, like `StructSerializer`. However, I don't think many
users are going through these types (I don't even know if we necessarily
want to keep those public either, but we'll save that for a different
PR). Additionally, this is just a debug feature that only affects error
messages, so it wouldn't have any drastically negative effect. It would
just result in the stack not being cleared properly if there were any
errors.

Lastly, this is not the most performant implementation since we now
fetch the `TypeInfo` an extra time. But I figured that for a debug tool,
it wouldn't matter too much.

### Feature

This also adds a `debug` feature, which enables the `debug_stack`
feature.

I added it because I think we may want to potentially add more debug
tools in the future, and this gives us a good framework for adding
those. Users who want all debug features, present and future, can just
set `debug`. If they only want this feature, then they can just use
`debug_stack`.

I also made the `debug` feature default to help capture the widest
audience (i.e. the users who want this feature but don't know they do).
However, if we think it's better as a non-default feature, I can change
it!

And if there's any bikeshedding around the name `debug_stack`, let me
know!

## Testing

Run the following command:

```
cargo test --package bevy_reflect --features debug_stack
```

---

## Changelog

- Added the `debug` and `debug_stack` features to `bevy_reflect`
- Updated the error messages returned by the reflection serializers and
deserializers to include more contextual information when the
`debug_stack` or `debug` feature is enabled
2024-09-09 17:52:40 +00:00
Gino Valente
245d03a78a
bevy_reflect: Update on_unimplemented attributes (#15110)
# Objective

Some of the new compile error messages are a little unclear (at least to
me). For example:

```
error[E0277]: `tests::foo::Bar` can not be created through reflection
   --> crates/bevy_reflect/src/lib.rs:679:18
    |
679 |         #[derive(Reflect)]
    |                  ^^^^^^^ the trait `from_reflect::FromReflect` is not implemented for `tests::foo::Bar`
    |
    = note: consider annotating `tests::foo::Bar` with `#[derive(Reflect)]` or `#[derive(FromReflect)]`
```

While the annotation makes it clear that `FromReflect` is missing, it's
not very clear from the main error message.

My IDE lists errors with only their message immediately present:

<p align="center">
<img width="700" alt="Image of said IDE listing errors with only their
message immediately present. These errors are as follows:
\"`tests::foo::Bar` can not be created through reflection\", \"The trait
bound `tests::foo::Bar: RegisterForReflection` is not satisfied\", and
\"The trait bound `tests::foo::Bar: type_info::MaybeTyped` is not
satisfied\""
src="https://github.com/user-attachments/assets/42c24051-9e8e-4555-8477-51a9407446aa">
</p>

This makes it hard to tell at a glance why my code isn't compiling.

## Solution

Updated all `on_unimplemented` attributes in `bevy_reflect` to mention
the relevant trait—either the actual trait or the one users actually
need to implement—as well as a small snippet of what not implementing
them means.

For example, failing to implement `TypePath` now mentions missing a
`TypePath` implementation. And failing to implement `DynamicTypePath`
now also mentions missing a `TypePath` implementation, since that's the
actual trait users need to implement (i.e. they shouldn't implement
`DynamicTypePath` directly).

Lastly, I also added some missing `on_unimplemented` attributes for
`MaybeTyped` and `RegisterForReflection` (which you can see in the image
above).

Here's how this looks in my IDE now:

<p align="center">
<img width="700" alt="Similar image as before showing the errors listed
by the IDE. This time the errors read as follows: \"`tests::foo::Bar`
does not implement `FromReflect` so cannot be reified through
reflection\", \"`tests::foo::Bar` does not implement
`GetTypeRegistration` so cannot be registered for reflection\", and
\"`tests::foo::Bar` does not implement `Typed` so cannot provide static
type information\""
src="https://github.com/user-attachments/assets/f6f8501f-0450-4f78-b84f-00e7a18d0533">
</p>


## Testing

You can test by adding the following code and verifying the compile
errors are correct:

```rust
#[derive(Reflect)]
struct Foo(Bar);

struct Bar;
```
2024-09-09 16:26:17 +00:00
BD103
6ec6a55645
Unify crate-level preludes (#15080)
# Objective

- Crate-level prelude modules, such as `bevy_ecs::prelude`, are plagued
with inconsistency! Let's fix it!

## Solution

Format all preludes based on the following rules:

1. All preludes should have brief documentation in the format of:
   > The _name_ prelude.
   >
> This includes the most common types in this crate, re-exported for
your convenience.
2. All documentation should be outer, not inner. (`///` instead of
`//!`.)
3. No prelude modules should be annotated with `#[doc(hidden)]`. (Items
within them may, though I'm not sure why this was done.)

## Testing

- I manually searched for the term `mod prelude` and updated all
occurrences by hand. 🫠

---------

Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2024-09-08 17:10:57 +00:00
Gino Valente
3892adcb47
bevy_reflect: Add Type type (#14838)
# Objective

Closes #7622.

I was working on adding support for reflecting generic functions and
found that I wanted to use an argument's `TypeId` for hashing and
comparison, but its `TypePath` for debugging and error messaging.

While I could just keep them separate, place them in a tuple or a local
struct or something, I think I see an opportunity to make a dedicate
type for this.

Additionally, we can use this type to clean up some duplication amongst
the type info structs in a manner similar to #7622.

## Solution

Added the `Type` type. This should be seen as the most basic
representation of a type apart from `TypeId`. It stores both the
`TypeId` of the type as well as its `TypePathTable`.

The `Hash` and `PartialEq` implementations rely on the `TypeId`, while
the `Debug` implementation relies on the `TypePath`.

This makes it especially useful as a key in a `HashMap` since we get the
speed of the `TypeId` hashing/comparisons with the readability of
`TypePath`.

With this type, we're able to reduce the duplication across the type
info structs by removing individual fields for `TypeId` and
`TypePathTable`, replacing them with a single `Type` field. Similarly,
we can remove many duplicate methods and replace it with a macro that
delegates to the stored `Type`.

### Caveats

It should be noted that this type is currently 3x larger than `TypeId`.
On my machine, it's 48 bytes compared to `TypeId`'s 16. While this
doesn't matter for `TypeInfo` since it would contain that data
regardless, it is something to keep in mind when using elsewhere.

## Testing

All tests should pass as normal:

```
cargo test --package bevy_reflect
```

---

## Showcase

`bevy_reflect` now exports a `Type` struct. This type contains both the
`TypeId` and the `TypePathTable` of the given type, allowing it to be
used like `TypeId` but have the debuggability of `TypePath`.

```rust
// We can create this for any type implementing `TypePath`:
let ty = Type::of::<String>();

// It has `Hash` and `Eq` impls powered by `TypeId`, making it useful for maps:
let mut map = HashMap::<Type, i32>::new();
map.insert(ty, 25);

// And it has a human-readable `Debug` representation:
let debug = format!("{:?}", map);
assert_eq!(debug, "{alloc::string::String: 25}");
```

## Migration Guide

Certain type info structs now only return their item types as `Type`
instead of exposing direct methods on them.

The following methods have been removed:

- `ArrayInfo::item_type_path_table`
- `ArrayInfo::item_type_id`
- `ArrayInfo::item_is`
- `ListInfo::item_type_path_table`
- `ListInfo::item_type_id`
- `ListInfo::item_is`
- `SetInfo::value_type_path_table`
- `SetInfo::value_type_id`
- `SetInfo::value_is`
- `MapInfo::key_type_path_table`
- `MapInfo::key_type_id`
- `MapInfo::key_is`
- `MapInfo::value_type_path_table`
- `MapInfo::value_type_id`
- `MapInfo::value_is`

Instead, access the `Type` directly using one of the new methods:

- `ArrayInfo::item_ty`
- `ListInfo::item_ty`
- `SetInfo::value_ty`
- `MapInfo::key_ty`
- `MapInfo::value_ty`

For example:

```rust
// BEFORE
let type_id = array_info.item_type_id();

// AFTER
let type_id = array_info.item_ty().id();
```
2024-08-25 17:57:07 +00:00
Lubba64
f9fbd08f9f
Implement Reflect for std::ops::Bound (#14861)
# Objective

- Fixes #14844

## Solution

- implement reflect using the `impl_reflect_value` macro

## Testing

- I wrote a test locally to understand and learn how reflection worked
on a basic level and to confirm that yes indeed the bound struct could
use the reflection traits that have been implemented for it.

note: I did remove a line that asked for bound to not have reflect
implemented in a test, since that's the point of this PR and the test
worked without the line so I am not sure what that was about, not sure
if that uncovers a deeper issue or not.
2024-08-22 23:01:38 +00:00
Gino Valente
2b4180ca8f
bevy_reflect: Function reflection terminology refactor (#14813)
# Objective

One of the changes in #14704 made `DynamicFunction` effectively the same
as `DynamicClosure<'static>`. This change meant that the de facto
function type would likely be `DynamicClosure<'static>` instead of the
intended `DynamicFunction`, since the former is much more flexible.

We _could_ explore ways of making `DynamicFunction` implement `Copy`
using some unsafe code, but it likely wouldn't be worth it. And users
would likely still reach for the convenience of
`DynamicClosure<'static>` over the copy-ability of `DynamicFunction`.

The goal of this PR is to fix this confusion between the two types.

## Solution

Firstly, the `DynamicFunction` type was removed. Again, it was no
different than `DynamicClosure<'static>` so it wasn't a huge deal to
remove.

Secondly, `DynamicClosure<'env>` and `DynamicClosureMut<'env>` were
renamed to `DynamicFunction<'env>` and `DynamicFunctionMut<'env>`,
respectively.

Yes, we still ultimately kept the naming of `DynamicFunction`, but
changed its behavior to that of `DynamicClosure<'env>`. We need a term
to refer to both functions and closures, and "function" was the best
option.


[Originally](https://discord.com/channels/691052431525675048/1002362493634629796/1274091992162242710),
I was going to go with "callable" as the replacement term to encompass
both functions and closures (e.g. `DynamciCallable<'env>`). However, it
was
[suggested](https://discord.com/channels/691052431525675048/1002362493634629796/1274653581777047625)
by @SkiFire13 that the simpler "function" term could be used instead.

While "callable" is perhaps the better umbrella term—being truly
ambiguous over functions and closures— "function" is more familiar, used
more often, easier to discover, and is subjectively just
"better-sounding".

## Testing

Most changes are purely swapping type names or updating documentation,
but you can verify everything still works by running the following
command:

```
cargo test --package bevy_reflect
```
2024-08-19 21:52:36 +00:00
Gino Valente
6183b56b5d
bevy_reflect: Reflect remote types (#6042)
# Objective

The goal with this PR is to allow the use of types that don't implement
`Reflect` within the reflection API.

Rust's [orphan
rule](https://doc.rust-lang.org/book/ch10-02-traits.html#implementing-a-trait-on-a-type)
prevents implementing a trait on an external type when neither type nor
trait are owned by the implementor. This means that if a crate,
`cool_rust_lib`, defines a type, `Foo`, then a user cannot use it with
reflection. What this means is that we have to ignore it most of the
time:

```rust
#[derive(Reflect)]
struct SomeStruct {
  #[reflect(ignore)]
  data: cool_rust_lib::Foo
}
```

Obviously, it's impossible to implement `Reflect` on `Foo`. But does it
*have* to be?

Most of reflection doesn't deal with concrete types— it's almost all
using `dyn Reflect`. And being very metadata-driven, it should
theoretically be possible. I mean,
[`serde`](https://serde.rs/remote-derive.html) does it.

## Solution

> Special thanks to @danielhenrymantilla for their help reviewing this
PR and offering wisdom wrt safety.

Taking a page out of `serde`'s book, this PR adds the ability to easily
use "remote types" with reflection. In this context, a "remote type" is
the external type for which we have no ability to implement `Reflect`.

This adds the `#[reflect_remote(...)]` attribute macro, which is used to
generate "remote type wrappers". All you have to do is define the
wrapper exactly the same as the remote type's definition:

```rust
// Pretend this is our external crate
mod cool_rust_lib {
  #[derive(Default)]
  struct Foo {
    pub value: String
  }
}

#[reflect_remote(cool_rust_lib::Foo)]
struct FooWrapper {
  pub value: String
}
```

> **Note:** All fields in the external type *must* be public. This could
be addressed with a separate getter/setter attribute either in this PR
or in another one.

The macro takes this user-defined item and transforms it into a newtype
wrapper around the external type, marking it as `#[repr(transparent)]`.
The fields/variants defined by the user are simply used to build out the
reflection impls.

Additionally, it generates an implementation of the new trait,
`ReflectRemote`, which helps prevent accidental misuses of this API.

Therefore, the output generated by the macro would look something like:

```rust
#[repr(transparent)]
struct FooWrapper(pub cool_rust_lib::Foo);

impl ReflectRemote for FooWrapper {
  type Remote = cool_rust_lib::Foo;

  // transmutation methods...
}

// reflection impls...
// these will acknowledge and make use of the `value` field
```

Internally, the reflection API will pass around the `FooWrapper` and
[transmute](https://doc.rust-lang.org/std/mem/fn.transmute.html) it
where necessary. All we have to do is then tell `Reflect` to do that. So
rather than ignoring the field, we tell `Reflect` to use our wrapper
using the `#[reflect(remote = ...)]` field attribute:

```rust
#[derive(Reflect)]
struct SomeStruct {
  #[reflect(remote = FooWrapper)]
  data: cool_rust_lib::Foo
}
```

#### Other Macros & Type Data

Because this macro consumes the defined item and generates a new one, we
can't just put our macros anywhere. All macros that should be passed to
the generated struct need to come *below* this macro. For example, to
derive `Default` and register its associated type data:

```rust
//  GOOD
#[reflect_remote(cool_rust_lib::Foo)]
#[derive(Default)]
#[reflect(Default)]
struct FooWrapper {
  pub value: String
}

//  BAD
#[derive(Default)]
#[reflect_remote(cool_rust_lib::Foo)]
#[reflect(Default)]
struct FooWrapper {
  pub value: String
}
```

#### Generics

Generics are forwarded to the generated struct as well. They should also
be defined in the same order:

```rust
#[reflect_remote(RemoteGeneric<'a, T1, T2>)]
struct GenericWrapper<'a, T1, T2> {
  pub foo: &'a T1,
  pub bar: &'a T2,
}
```

> Naming does *not* need to match the original definition's. Only order
matters here.

> Also note that the code above is just a demonstration and doesn't
actually compile since we'd need to enforce certain bounds (e.g. `T1:
Reflect`, `'a: 'static`, etc.)

#### Nesting

And, yes, you can nest remote types:

```rust
#[reflect_remote(RemoteOuter)]
struct OuterWrapper {
  #[reflect(remote = InnerWrapper)]
  pub inner: RemoteInner
}

#[reflect_remote(RemoteInner)]
struct InnerWrapper(usize);
```

#### Assertions

This macro will also generate some compile-time assertions to ensure
that the correct types are used. It's important we catch this early so
users don't have to wait for something to panic. And it also helps keep
our `unsafe` a little safer.

For example, a wrapper definition that does not match its corresponding
remote type will result in an error:

```rust
mod external_crate {
  pub struct TheirStruct(pub u32);
}

#[reflect_remote(external_crate::TheirStruct)]
struct MyStruct(pub String); // ERROR: expected type `u32` but found `String`
```

<details>
<summary>Generated Assertion</summary>

```rust
const _: () = {
  #[allow(non_snake_case)]
  #[allow(unused_variables)]
  #[allow(unused_assignments)]
  #[allow(unreachable_patterns)]
  #[allow(clippy::multiple_bound_locations)]
  fn assert_wrapper_definition_matches_remote_type(
    mut __remote__: external_crate::TheirStruct,
  ) {
    __remote__.0 = (|| -> ::core::option::Option<String> { None })().unwrap();
  }
};
```

</details>

Additionally, using the incorrect type in a `#[reflect(remote = ...)]`
attribute should result in an error:

```rust
mod external_crate {
  pub struct TheirFoo(pub u32);
  pub struct TheirBar(pub i32);
}

#[reflect_remote(external_crate::TheirFoo)]
struct MyFoo(pub u32);

#[reflect_remote(external_crate::TheirBar)]
struct MyBar(pub i32);

#[derive(Reflect)]
struct MyStruct {
  #[reflect(remote = MyBar)] // ERROR: expected type `TheirFoo` but found struct `TheirBar`
  foo: external_crate::TheirFoo
}
```

<details>
<summary>Generated Assertion</summary>

```rust
const _: () = {
    struct RemoteFieldAssertions;
    impl RemoteFieldAssertions {
        #[allow(non_snake_case)]
        #[allow(clippy::multiple_bound_locations)]
        fn assert__foo__is_valid_remote() {
            let _: <MyBar as bevy_reflect::ReflectRemote>::Remote = (|| -> ::core::option::Option<external_crate::TheirFoo> {
              None
            })().unwrap();
        }
    }
};
```

</details>

### Discussion

There are a couple points that I think still need discussion or
validation.

- [x] 1. `Any` shenanigans

~~If we wanted to downcast our remote type from a `dyn Reflect`, we'd
have to first downcast to the wrapper then extract the inner type. This
PR has a [commit](b840db9f74cb6d357f951cb11b150d46bac89ee2) that
addresses this by making all the `Reflect::*any` methods return the
inner type rather than the wrapper type. This allows us to downcast
directly to our remote type.~~

~~However, I'm not sure if this is something we want to do. For
unknowing users, it could be confusing and seemingly inconsistent. Is it
worth keeping? Or should this behavior be removed?~~

I think this should be fine. The remote wrapper is an implementation
detail and users should not need to downcast to the wrapper type. Feel
free to let me know if there are other opinions on this though!

- [x] 2. Implementing `Deref/DerefMut` and `From`

~~We don't currently do this, but should we implement other traits on
the generated transparent struct? We could implement `Deref`/`DerefMut`
to easily access the inner type. And we could implement `From` for
easier conversion between the two types (e.g. `T: Into<Foo>`).~~ As
mentioned in the comments, we probably don't need to do this. Again, the
remote wrapper is an implementation detail, and should generally not be
used directly.
     
- [x] 3. ~~Should we define a getter/setter field attribute in this PR
as well or leave it for a future one?~~ I think this should be saved for
a future PR

- [ ] 4. Any foreseeable issues with this implementation?

#### Alternatives

One alternative to defining our own `ReflectRemote` would be to use
[bytemuck's
`TransparentWrapper`](https://docs.rs/bytemuck/1.13.1/bytemuck/trait.TransparentWrapper.html)
(as suggested by @danielhenrymantilla).

This is definitely a viable option, as `ReflectRemote` is pretty much
the same thing as `TransparentWrapper`. However, the cost would be
bringing in a new crate— though, it is already in use in a few other
sub-crates like bevy_render.

I think we're okay just defining `ReflectRemote` ourselves, but we can
go the bytemuck route if we'd prefer offloading that work to another
crate.

---

## Changelog

* Added the `#[reflect_remote(...)]` attribute macro to allow `Reflect`
to be used on remote types
* Added `ReflectRemote` trait for ensuring proper remote wrapper usage
2024-08-12 19:12:53 +00:00
Tau Gärtli
aab1f8e435
Use #[doc(fake_variadic)] to improve docs readability (#14703)
# Objective

- Fixes #14697

## Solution

This PR modifies the existing `all_tuples!` macro to optionally accept a
`#[doc(fake_variadic)]` attribute in its input. If the attribute is
present, each invocation of the impl macro gets the correct attributes
(i.e. the first impl receives `#[doc(fake_variadic)]` while the other
impls are hidden using `#[doc(hidden)]`.
Impls for the empty tuple (unit type) are left untouched (that's what
the [standard
library](https://doc.rust-lang.org/std/cmp/trait.PartialEq.html#impl-PartialEq-for-())
and
[serde](https://docs.rs/serde/latest/serde/trait.Serialize.html#impl-Serialize-for-())
do).

To work around https://github.com/rust-lang/cargo/issues/8811 and to get
impls on re-exports to correctly show up as variadic, `--cfg docsrs_dep`
is passed when building the docs for the toplevel `bevy` crate.

`#[doc(fake_variadic)]` only works on tuples and fn pointers, so impls
for structs like `AnyOf<(T1, T2, ..., Tn)>` are unchanged.

## Testing

I built the docs locally using `RUSTDOCFLAGS='--cfg docsrs'
RUSTFLAGS='--cfg docsrs_dep' cargo +nightly doc --no-deps --workspace`
and checked the documentation page of a trait both in its original crate
and the re-exported version in `bevy`.
The description should correctly mention for how many tuple items the
trait is implemented.

I added `rustc-args` for docs.rs to the `bevy` crate, I hope there
aren't any other notable crates that re-export `#[doc(fake_variadic)]`
traits.

---

## Showcase

`bevy_ecs::query::QueryData`:
<img width="1015" alt="Screenshot 2024-08-12 at 16 41 28"
src="https://github.com/user-attachments/assets/d40136ed-6731-475f-91a0-9df255cd24e3">

`bevy::ecs::query::QueryData` (re-export):
<img width="1005" alt="Screenshot 2024-08-12 at 16 42 57"
src="https://github.com/user-attachments/assets/71d44cf0-0ab0-48b0-9a51-5ce332594e12">

## Original Description

<details>

Resolves #14697

Submitting as a draft for now, very WIP.

Unfortunately, the docs don't show the variadics nicely when looking at
reexported items.
For example:

`bevy_ecs::bundle::Bundle` correctly shows the variadic impl:

![image](https://github.com/user-attachments/assets/90bf8af1-1d1f-4714-9143-cdd3d0199998)

while `bevy::ecs::bundle::Bundle` (the reexport) shows all the impls
(not good):

![image](https://github.com/user-attachments/assets/439c428e-f712-465b-bec2-481f7bf5870b)

Built using `RUSTDOCFLAGS='--cfg docsrs' cargo +nightly doc --workspace
--no-deps` (`--no-deps` because of wgpu-core).

Maybe I missed something or this is a limitation in the *totally not
private* `#[doc(fake_variadic)]` thingy. In any case I desperately need
some sleep now :))

</details>
2024-08-12 18:54:33 +00:00
radiish
6ab8767d3b
reflect: implement the unique reflect rfc (#7207)
# Objective

- Implements the [Unique Reflect
RFC](https://github.com/nicopap/rfcs/blob/bevy-reflect-api/rfcs/56-better-reflect.md).

## Solution

- Implements the RFC.
- This implementation differs in some ways from the RFC:
- In the RFC, it was suggested `Reflect: Any` but `PartialReflect:
?Any`. During initial implementation I tried this, but we assume the
`PartialReflect: 'static` in a lot of places and the changes required
crept out of the scope of this PR.
- `PartialReflect::try_into_reflect` originally returned `Option<Box<dyn
Reflect>>` but i changed this to `Result<Box<dyn Reflect>, Box<dyn
PartialReflect>>` since the method takes by value and otherwise there
would be no way to recover the type. `as_full` and `as_full_mut` both
still return `Option<&(mut) dyn Reflect>`.

---

## Changelog

- Added `PartialReflect`.
- `Reflect` is now a subtrait of `PartialReflect`.
- Moved most methods on `Reflect` to the new `PartialReflect`.
- Added `PartialReflect::{as_partial_reflect, as_partial_reflect_mut,
into_partial_reflect}`.
- Added `PartialReflect::{try_as_reflect, try_as_reflect_mut,
try_into_reflect}`.
- Added `<dyn PartialReflect>::{try_downcast_ref, try_downcast_mut,
try_downcast, try_take}` supplementing the methods on `dyn Reflect`.

## Migration Guide

- Most instances of `dyn Reflect` should be changed to `dyn
PartialReflect` which is less restrictive, however trait bounds should
generally stay as `T: Reflect`.
- The new `PartialReflect::{as_partial_reflect, as_partial_reflect_mut,
into_partial_reflect, try_as_reflect, try_as_reflect_mut,
try_into_reflect}` methods as well as `Reflect::{as_reflect,
as_reflect_mut, into_reflect}` will need to be implemented for manual
implementors of `Reflect`.

## Future Work

- This PR is designed to be followed up by another "Unique Reflect Phase
2" that addresses the following points:
- Investigate making serialization revolve around `Reflect` instead of
`PartialReflect`.
- [Remove the `try_*` methods on `dyn PartialReflect` since they are
stop
gaps](https://github.com/bevyengine/bevy/pull/7207#discussion_r1083476050).
- Investigate usages like `ReflectComponent`. In the places they
currently use `PartialReflect`, should they be changed to use `Reflect`?
- Merging this opens the door to lots of reflection features we haven't
been able to implement.
- We could re-add [the `Reflectable`
trait](8e3488c880/crates/bevy_reflect/src/reflect.rs (L337-L342))
and make `FromReflect` a requirement to improve [`FromReflect`
ergonomics](https://github.com/bevyengine/rfcs/pull/59). This is
currently not possible because dynamic types cannot sensibly be
`FromReflect`.
  - Since this is an alternative to #5772, #5781 would be made cleaner.

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2024-08-12 17:01:41 +00:00
Robert Walter
52a2a3b146
Dedicated Reflect implementation for Set-like things (#13014)
# Objective

I just wanted to inspect `HashSet`s in `bevy-inspector-egui` but I
noticed that it didn't work for some reason. A few minutes later I found
myself looking into the bevy reflect impls noticing that `HashSet`s have
been covered only rudimentary up until now.

## Solution

I'm not sure if this is overkill (especially the first bullet), but
here's a list of the changes:

- created a whole new trait and enum variants for `ReflectRef` and the
like called `Set`
- mostly oriented myself at the `Map` trait and made the necessary
changes until RA was happy
- create macro `impl_reflect_for_hashset!` and call it on `std::HashSet`
and `hashbrown::HashSet`

Extra notes:

- no `get_mut` or `get_mut_at` mirroring the `std::HashSet`
- `insert[_boxed]` and `remove` return `bool` mirroring `std::HashSet`,
additionally that bool is reflect as I thought that would be how we
handle things in bevy reflect, but I'm not sure on this
- ser/de are handled via `SeqAccess`
- I'm not sure about the general deduplication property of this impl of
`Set` that is generally expected? I'm also not sure yet if `Map` does
provide this. This mainly refers to the `Dynamic[...]` structs
- I'm not sure if there are other methods missing from the `trait`, I
felt like `contains` or the set-operations (union/diff/...) could've
been helpful, but I wanted to get out the bare minimum for feedback
first

---

## Changelog

### Added
- `Set` trait for `bevy_reflect`

### Changed
- `std::collections::HashSet` and `bevy_utils::hashbrown::HashSet` now
implement a more complete set of reflect functionalities instead of
"just" `reflect_value`
- `TypeInfo` contains a new variant `Set` that contains `SetInfo`
- `ReflectKind` contains a new variant `Set`
- `ReflectRef` contains a new variant `Set`
- `ReflectMut` contains a new variant `Set`
- `ReflectOwned` contains a new variant `Set`

## Migration Guide

- The new `Set` variants on the enums listed in the change section
should probably be considered by people working with this level of the
lib
### Help wanted! 

I'm not sure if this change is able to break code. From my understanding
it shouldn't since we just add functionality but I'm not sure yet if
theres anything missing from my impl that would be normally provided by
`impl_reflect_value!`
2024-07-24 19:43:26 +00:00
SpecificProtagonist
ab255aefc6
Implement FromIterator/IntoIterator for dynamic types (#14250)
# Objective

Implement FromIterator/IntoIterator for dynamic types where missing

Note:
- can't impl `IntoIterator` for `&Array` & co because of orphan rules
- `into_iter().collect()` is a no-op for `Vec`s because of
specialization

---

## Migration Guide

- Change `DynamicArray::from_vec` to `DynamicArray::from_iter`
2024-07-15 15:38:11 +00:00
Gino Valente
aa241672e1
bevy_reflect: Nested TypeInfo getters (#13321)
# Objective

Right now, `TypeInfo` can be accessed directly from a type using either
`Typed::type_info` or `Reflect::get_represented_type_info`.

However, once that `TypeInfo` is accessed, any nested types must be
accessed via the `TypeRegistry`.

```rust
#[derive(Reflect)]
struct Foo {
  bar: usize
}

let registry = TypeRegistry::default();

let TypeInfo::Struct(type_info) = Foo::type_info() else {
  panic!("expected struct info");
};

let field = type_info.field("bar").unwrap();

let field_info = registry.get_type_info(field.type_id()).unwrap();
assert!(field_info.is::<usize>());;
```

## Solution

Enable nested types within a `TypeInfo` to be retrieved directly.

```rust
#[derive(Reflect)]
struct Foo {
  bar: usize
}

let TypeInfo::Struct(type_info) = Foo::type_info() else {
  panic!("expected struct info");
};

let field = type_info.field("bar").unwrap();

let field_info = field.type_info().unwrap();
assert!(field_info.is::<usize>());;
```

The particular implementation was chosen for two reasons.

Firstly, we can't just store `TypeInfo` inside another `TypeInfo`
directly. This is because some types are recursive and would result in a
deadlock when trying to create the `TypeInfo` (i.e. it has to create the
`TypeInfo` before it can use it, but it also needs the `TypeInfo` before
it can create it). Therefore, we must instead store the function so it
can be retrieved lazily.

I had considered also using a `OnceLock` or something to lazily cache
the info, but I figured we can look into optimizations later. The API
should remain the same with or without the `OnceLock`.

Secondly, a new wrapper trait had to be introduced: `MaybeTyped`. Like
`RegisterForReflection`, this trait is `#[doc(hidden)]` and only exists
so that we can properly handle dynamic type fields without requiring
them to implement `Typed`. We don't want dynamic types to implement
`Typed` due to the fact that it would make the return type
`Option<&'static TypeInfo>` for all types even though only the dynamic
types ever need to return `None` (see #6971 for details).

Users should never have to interact with this trait as it has a blanket
impl for all `Typed` types. And `Typed` is automatically implemented
when deriving `Reflect` (as it is required).

The one downside is we do need to return `Option<&'static TypeInfo>`
from all these new methods so that we can handle the dynamic cases. If
we didn't have to, we'd be able to get rid of the `Option` entirely. But
I think that's an okay tradeoff for this one part of the API, and keeps
the other APIs intact.

## Testing

This PR contains tests to verify everything works as expected. You can
test locally by running:

```
cargo test --package bevy_reflect
```

---

## Changelog

### Public Changes

- Added `ArrayInfo::item_info` method
- Added `NamedField::type_info` method
- Added `UnnamedField::type_info` method
- Added `ListInfo::item_info` method
- Added `MapInfo::key_info` method
- Added `MapInfo::value_info` method
- All active fields now have a `Typed` bound (remember that this is
automatically satisfied for all types that derive `Reflect`)

### Internal Changes

- Added `MaybeTyped` trait

## Migration Guide

All active fields for reflected types (including lists, maps, tuples,
etc.), must implement `Typed`. For the majority of users this won't have
any visible impact.

However, users implementing `Reflect` manually may need to update their
types to implement `Typed` if they weren't already.

Additionally, custom dynamic types will need to implement the new hidden
`MaybeTyped` trait.
2024-07-15 00:40:07 +00:00
Gino Valente
e512cb602c
bevy_reflect: TypeInfo casting methods (#13320)
# Objective

There are times when we might know the type of a `TypeInfo` ahead of
time. Or we may have already checked it one way or another.

In such cases, it's a bit cumbersome to have to pattern match every time
we want to access the nested info:

```rust
if let TypeInfo::List(info) = <Vec<i32>>::type_info() {
  // ...
} else {
  panic!("expected list info");
}
```

Ideally, there would be a way to simply perform the cast down to
`ListInfo` since we already know it will succeed.

Or even if we don't, perhaps we just want a cleaner way of exiting a
function early (i.e. with the `?` operator).

## Solution

Taking a bit from
[`mirror-mirror`](https://docs.rs/mirror-mirror/latest/mirror_mirror/struct.TypeDescriptor.html#implementations),
`TypeInfo` now has methods for attempting a cast into the variant's info
type.

```rust
let info = <Vec<i32>>::type_info().as_list().unwrap();
// ...
```

These new conversion methods return a `Result` where the error type is a
new `TypeInfoError` enum.

A `Result` was chosen as the return type over `Option` because if we do
choose to `unwrap` it, the error message will give us some indication of
what went wrong. In other words, it can truly replace those instances
where we were panicking in the `else` case.

### Open Questions

1. Should the error types instead be a struct? I chose an enum for
future-proofing, but right now it only has one error state.
Alternatively, we could make it a reflect-wide casting error so it could
be used for similar methods on `ReflectRef` and friends.
2. I was going to do it in a separate PR but should I just go ahead and
add similar methods to `ReflectRef`, `ReflectMut`, and `ReflectOwned`? 🤔
3. Should we name these `try_as_***` instead of `as_***` since they
return a `Result`?

## Testing

You can test locally by running:

```
cargo test --package bevy_reflect
```

---

## Changelog

### Added

- `TypeInfoError` enum
- `TypeInfo::kind` method
- `TypeInfo::as_struct` method
- `TypeInfo::as_tuple_struct` method
- `TypeInfo::as_tuple` method
- `TypeInfo::as_list` method
- `TypeInfo::as_array` method
- `TypeInfo::as_map` method
- `TypeInfo::as_enum` method
- `TypeInfo::as_value` method
- `VariantInfoError` enum
- `VariantInfo::variant_type` method
- `VariantInfo::as_unit_variant` method
- `VariantInfo::as_tuple_variant` method
- `VariantInfo::as_struct_variant` method
2024-07-14 20:10:31 +00:00
Gino Valente
99c9218b56
bevy_reflect: Feature-gate function reflection (#14174)
# Objective

Function reflection requires a lot of macro code generation in the form
of several `all_tuples!` invocations, as well as impls generated in the
`Reflect` derive macro.

Seeing as function reflection is currently a bit more niche, it makes
sense to gate it all behind a feature.

## Solution

Add a `functions` feature to `bevy_reflect`, which can be enabled in
Bevy using the `reflect_functions` feature.

## Testing

You can test locally by running:

```
cargo test --package bevy_reflect
```

That should ensure that everything still works with the feature
disabled.

To test with the feature on, you can run:

```
cargo test --package bevy_reflect --features functions
```

---

## Changelog

- Moved function reflection behind a Cargo feature
(`bevy/reflect_functions` and `bevy_reflect/functions`)
- Add `IntoFunction` export in `bevy_reflect::prelude`

## Internal Migration Guide

> [!important]
> Function reflection was introduced as part of the 0.15 dev cycle. This
migration guide was written for developers relying on `main` during this
cycle, and is not a breaking change coming from 0.14.

Function reflection is now gated behind a feature. To use function
reflection, enable the feature:
- If using `bevy_reflect` directly, enable the `functions` feature
- If using `bevy`, enable the `reflect_functions` feature
2024-07-14 15:55:31 +00:00
Gino Valente
276dd04001
bevy_reflect: Function reflection (#13152)
# Objective

We're able to reflect types sooooooo... why not functions?

The goal of this PR is to make functions callable within a dynamic
context, where type information is not readily available at compile
time.

For example, if we have a function:

```rust
fn add(left: i32, right: i32) -> i32 {
  left + right
}
```

And two `Reflect` values we've already validated are `i32` types:

```rust
let left: Box<dyn Reflect> = Box::new(2_i32);
let right: Box<dyn Reflect> = Box::new(2_i32);
```

We should be able to call `add` with these values:

```rust
// ?????
let result: Box<dyn Reflect> = add.call_dynamic(left, right);
```

And ideally this wouldn't just work for functions, but methods and
closures too!

Right now, users have two options:

1. Manually parse the reflected data and call the function themselves
2. Rely on registered type data to handle the conversions for them

For a small function like `add`, this isn't too bad. But what about for
more complex functions? What about for many functions?

At worst, this process is error-prone. At best, it's simply tedious.

And this is assuming we know the function at compile time. What if we
want to accept a function dynamically and call it with our own
arguments?

It would be much nicer if `bevy_reflect` could alleviate some of the
problems here.

## Solution

Added function reflection!

This adds a `DynamicFunction` type to wrap a function dynamically. This
can be called with an `ArgList`, which is a dynamic list of
`Reflect`-containing `Arg` arguments. It returns a `FunctionResult`
which indicates whether or not the function call succeeded, returning a
`Reflect`-containing `Return` type if it did succeed.

Many functions can be converted into this `DynamicFunction` type thanks
to the `IntoFunction` trait.

Taking our previous `add` example, this might look something like
(explicit types added for readability):

```rust
fn add(left: i32, right: i32) -> i32 {
  left + right
}

let mut function: DynamicFunction = add.into_function();
let args: ArgList = ArgList::new().push_owned(2_i32).push_owned(2_i32);
let result: Return = function.call(args).unwrap();
let value: Box<dyn Reflect> = result.unwrap_owned();
assert_eq!(value.take::<i32>().unwrap(), 4);
```

And it also works on closures:

```rust
let add = |left: i32, right: i32| left + right;

let mut function: DynamicFunction = add.into_function();
let args: ArgList = ArgList::new().push_owned(2_i32).push_owned(2_i32);
let result: Return = function.call(args).unwrap();
let value: Box<dyn Reflect> = result.unwrap_owned();
assert_eq!(value.take::<i32>().unwrap(), 4);
```

As well as methods:

```rust
#[derive(Reflect)]
struct Foo(i32);

impl Foo {
  fn add(&mut self, value: i32) {
    self.0 += value;
  }
}

let mut foo = Foo(2);

let mut function: DynamicFunction = Foo::add.into_function();
let args: ArgList = ArgList::new().push_mut(&mut foo).push_owned(2_i32);
function.call(args).unwrap();
assert_eq!(foo.0, 4);
```

### Limitations

While this does cover many functions, it is far from a perfect system
and has quite a few limitations. Here are a few of the limitations when
using `IntoFunction`:

1. The lifetime of the return value is only tied to the lifetime of the
first argument (useful for methods). This means you can't have a
function like `(a: i32, b: &i32) -> &i32` without creating the
`DynamicFunction` manually.
2. Only 15 arguments are currently supported. If the first argument is a
(mutable) reference, this number increases to 16.
3. Manual implementations of `Reflect` will need to implement the new
`FromArg`, `GetOwnership`, and `IntoReturn` traits in order to be used
as arguments/return types.

And some limitations of `DynamicFunction` itself:

1. All arguments share the same lifetime, or rather, they will shrink to
the shortest lifetime.
2. Closures that capture their environment may need to have their
`DynamicFunction` dropped before accessing those variables again (there
is a `DynamicFunction::call_once` to make this a bit easier)
3. All arguments and return types must implement `Reflect`. While not a
big surprise coming from `bevy_reflect`, this implementation could
actually still work by swapping `Reflect` out with `Any`. Of course,
that makes working with the arguments and return values a bit harder.
4. Generic functions are not supported (unless they have been manually
monomorphized)

And general, reflection gotchas:

1. `&str` does not implement `Reflect`. Rather, `&'static str`
implements `Reflect` (the same is true for `&Path` and similar types).
This means that `&'static str` is considered an "owned" value for the
sake of generating arguments. Additionally, arguments and return types
containing `&str` will assume it's `&'static str`, which is almost never
the desired behavior. In these cases, the only solution (I believe) is
to use `&String` instead.

### Followup Work

This PR is the first of two PRs I intend to work on. The second PR will
aim to integrate this new function reflection system into the existing
reflection traits and `TypeInfo`. The goal would be to register and call
a reflected type's methods dynamically.

I chose not to do that in this PR since the diff is already quite large.
I also want the discussion for both PRs to be focused on their own
implementation.

Another followup I'd like to do is investigate allowing common container
types as a return type, such as `Option<&[mut] T>` and `Result<&[mut] T,
E>`. This would allow even more functions to opt into this system. I
chose to not include it in this one, though, for the same reasoning as
previously mentioned.

### Alternatives

One alternative I had considered was adding a macro to convert any
function into a reflection-based counterpart. The idea would be that a
struct that wraps the function would be created and users could specify
which arguments and return values should be `Reflect`. It could then be
called via a new `Function` trait.

I think that could still work, but it will be a fair bit more involved,
requiring some slightly more complex parsing. And it of course is a bit
more work for the user, since they need to create the type via macro
invocation.

It also makes registering these functions onto a type a bit more
complicated (depending on how it's implemented).

For now, I think this is a fairly simple, yet powerful solution that
provides the least amount of friction for users.

---

## Showcase

Bevy now adds support for storing and calling functions dynamically
using reflection!

```rust
// 1. Take a standard Rust function
fn add(left: i32, right: i32) -> i32 {
  left + right
}

// 2. Convert it into a type-erased `DynamicFunction` using the `IntoFunction` trait
let mut function: DynamicFunction = add.into_function();
// 3. Define your arguments from reflected values
let args: ArgList = ArgList::new().push_owned(2_i32).push_owned(2_i32);
// 4. Call the function with your arguments
let result: Return = function.call(args).unwrap();
// 5. Extract the return value
let value: Box<dyn Reflect> = result.unwrap_owned();
assert_eq!(value.take::<i32>().unwrap(), 4);
```

## Changelog

#### TL;DR

- Added support for function reflection
- Added a new `Function Reflection` example:
ba727898f2/examples/reflection/function_reflection.rs (L1-L157)

#### Details

Added the following items:

- `ArgError` enum
- `ArgId` enum
- `ArgInfo` struct
- `ArgList` struct
- `Arg` enum
- `DynamicFunction` struct
- `FromArg` trait (derived with `derive(Reflect)`)
- `FunctionError` enum
- `FunctionInfo` struct
- `FunctionResult` alias
- `GetOwnership` trait (derived with `derive(Reflect)`)
- `IntoFunction` trait (with blanket implementation)
- `IntoReturn` trait (derived with `derive(Reflect)`)
- `Ownership` enum
- `ReturnInfo` struct
- `Return` enum

---------

Co-authored-by: Periwink <charlesbour@gmail.com>
2024-07-01 13:49:08 +00:00
Jan Hohenheim
6273227e09
Fix lints introduced in Rust beta 1.80 (#13899)
Resolves #13895

Mostly just involves being more explicit about which parts of the docs
belong to a list and which begin a new paragraph.
- found a few docs that were malformed because of exactly this, so I
fixed that by introducing a paragraph
- added indentation to nearly all multiline lists
- fixed a few minor typos
- added `#[allow(dead_code)]` to types that are needed to test
annotations but are never constructed
([here](https://github.com/bevyengine/bevy/pull/13899/files#diff-b02b63604e569c8577c491e7a2030d456886d8f6716eeccd46b11df8aac75dafR1514)
and
[here](https://github.com/bevyengine/bevy/pull/13899/files#diff-b02b63604e569c8577c491e7a2030d456886d8f6716eeccd46b11df8aac75dafR1523))
- verified that  `cargo +beta run -p ci -- lints` passes
- verified that `cargo +beta run -p ci -- test` passes
2024-06-17 17:22:01 +00:00
Wuketuke
d45bcfd043
improved the error message by insert_boxed (issue #13646) (again) (#13706)
previously I worked on fixing issue #13646, back when the error message
did not include the type at all.
But that error message had room for improvement, so I included the
feedback of @alice-i-cecile and @MrGVSV.
The error message will now read `the given key (of type
bevy_reflect::tests::Foo) does not support hashing` or 'the given key
(of type bevy_reflect::DynamicStruct) does not support hashing' in case
of a dynamic struct that represents a hashable struct

i also added a new unit test for this new behaviour
(`reflect_map_no_hash_dynamic`).
Fixes #13646 (again)

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2024-06-07 20:56:16 +00:00
Wuketuke
2eb9d5cc38
hashing error in bevy_reflect now includes the type (bevyengine#13646) (#13691)
# Objective
If you try to add an object to the hashmap that is not capable of
hashing, the program panics. For easier debugging, the type for that
object should be included in the error message.

Fixes #13646.

## Solution
initially i tried calling std::any::type_name_of_val. this had the
problem that it would print something like dyn Box<dyn Reflect>, not
helpful. But since these objects all implement Reflect, i used
Reflect::type_path() instead. Previously, the error message was part of
a constant called HASH_ERROR. i changed that to a macro called
hash_error to print the type of that object more easily

## Testing
i adapted the unit test reflect_map_no_hash to expect the type in that
panic aswell

since this is my first contribution, please let me know if i have done
everything properly
2024-06-05 19:41:23 +00:00