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unique_components allows read access to !Sync resources from any thread #6282

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james7132 opened this issue Oct 17, 2022 · 1 comment
Closed

unique_components allows read access to !Sync resources from any thread #6282

james7132 opened this issue Oct 17, 2022 · 1 comment
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A-ECS Entities, components, systems, and events C-Bug An unexpected or incorrect behavior P-Unsound A bug that results in undefined compiler behavior

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@james7132
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Archetype::unique_components allows access to read any !Sync resource from any arbitrary thread. This allows for aliasing accesses to these resources given a &World. This is unsound.
@james7132 james7132 added C-Bug An unexpected or incorrect behavior A-ECS Entities, components, systems, and events P-Unsound A bug that results in undefined compiler behavior labels Oct 17, 2022
@james7132 james7132 mentioned this issue Oct 18, 2022
Closed
bors bot pushed a commit that referenced this issue Oct 24, 2022
@james7132
Extract Resources into their own dedicated storage (#4809)
2b96530 
# Objective
At least partially addresses #6282.

Resources are currently stored as a dedicated Resource archetype (ID 1). This allows for easy code reusability, but unnecessarily adds 72 bytes (on 64-bit systems) to the struct that is only used for that one archetype. It also requires several fields to be `pub(crate)` which isn't ideal.

This should also remove one sparse-set lookup from fetching, inserting, and removing resources from a `World`.

## Solution

- Add `Resources` parallel to `Tables` and `SparseSets` and extract the functionality used by `Archetype` in it.
- Remove `unique_components` from `Archetype`
- Remove the `pub(crate)` on `Archetype::components`.
- Remove `ArchetypeId::RESOURCE`
- Remove `Archetypes::resource` and `Archetypes::resource_mut`

---

## Changelog
Added: `Resources` type to store resources.
Added: `Storages::resource`
Removed: `ArchetypeId::RESOURCE`
Removed: `Archetypes::resource` and `Archetypes::resources`
Removed: `Archetype::unique_components` and `Archetypes::unique_components_mut`

## Migration Guide
Resources have been moved to `Resources` under `Storages` in `World`. All code dependent on `Archetype::unique_components(_mut)` should access it via `world.storages().resources()` instead.

All APIs accessing the raw data of individual resources (mutable *and* read-only) have been removed as these APIs allowed for unsound unsafe code. All usages of these APIs should be changed to use `World::{get, insert, remove}_resource`.
@james7132
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After #4809, this seems to be mitigated from a user-facing perspective, but otherwise remains untouched from an internal perspective.

james7132 added a commit to james7132/bevy that referenced this issue Oct 28, 2022
@james7132
Extract Resources into their own dedicated storage (bevyengine#4809)
abf817f 
At least partially addresses bevyengine#6282.

Resources are currently stored as a dedicated Resource archetype (ID 1). This allows for easy code reusability, but unnecessarily adds 72 bytes (on 64-bit systems) to the struct that is only used for that one archetype. It also requires several fields to be `pub(crate)` which isn't ideal.

This should also remove one sparse-set lookup from fetching, inserting, and removing resources from a `World`.

- Add `Resources` parallel to `Tables` and `SparseSets` and extract the functionality used by `Archetype` in it.
- Remove `unique_components` from `Archetype`
- Remove the `pub(crate)` on `Archetype::components`.
- Remove `ArchetypeId::RESOURCE`
- Remove `Archetypes::resource` and `Archetypes::resource_mut`

---

Added: `Resources` type to store resources.
Added: `Storages::resource`
Removed: `ArchetypeId::RESOURCE`
Removed: `Archetypes::resource` and `Archetypes::resources`
Removed: `Archetype::unique_components` and `Archetypes::unique_components_mut`

Resources have been moved to `Resources` under `Storages` in `World`. All code dependent on `Archetype::unique_components(_mut)` should access it via `world.storages().resources()` instead.

All APIs accessing the raw data of individual resources (mutable *and* read-only) have been removed as these APIs allowed for unsound unsafe code. All usages of these APIs should be changed to use `World::{get, insert, remove}_resource`.
@james7132 james7132 mentioned this issue Dec 3, 2022
Closed
Pietrek14 pushed a commit to Pietrek14/bevy that referenced this issue Dec 17, 2022
@james7132 @Pietrek14
Extract Resources into their own dedicated storage (bevyengine#4809)
84de928 
# Objective
At least partially addresses bevyengine#6282.

Resources are currently stored as a dedicated Resource archetype (ID 1). This allows for easy code reusability, but unnecessarily adds 72 bytes (on 64-bit systems) to the struct that is only used for that one archetype. It also requires several fields to be `pub(crate)` which isn't ideal.

This should also remove one sparse-set lookup from fetching, inserting, and removing resources from a `World`.

## Solution

- Add `Resources` parallel to `Tables` and `SparseSets` and extract the functionality used by `Archetype` in it.
- Remove `unique_components` from `Archetype`
- Remove the `pub(crate)` on `Archetype::components`.
- Remove `ArchetypeId::RESOURCE`
- Remove `Archetypes::resource` and `Archetypes::resource_mut`

---

## Changelog
Added: `Resources` type to store resources.
Added: `Storages::resource`
Removed: `ArchetypeId::RESOURCE`
Removed: `Archetypes::resource` and `Archetypes::resources`
Removed: `Archetype::unique_components` and `Archetypes::unique_components_mut`

## Migration Guide
Resources have been moved to `Resources` under `Storages` in `World`. All code dependent on `Archetype::unique_components(_mut)` should access it via `world.storages().resources()` instead.

All APIs accessing the raw data of individual resources (mutable *and* read-only) have been removed as these APIs allowed for unsound unsafe code. All usages of these APIs should be changed to use `World::{get, insert, remove}_resource`.
@bors bors bot closed this as completed in aaf384a Jan 9, 2023
james7132 added a commit to james7132/bevy that referenced this issue Jan 21, 2023
@james7132
Panic on dropping NonSend in non-origin thread. (bevyengine#6534)
845b956 
# Objective

Fixes bevyengine#3310. Fixes bevyengine#6282. Fixes bevyengine#6278. Fixes bevyengine#3666.

## Solution
Split out `!Send` resources into `NonSendResources`. Add a `origin_thread_id` to all `!Send` Resources, check it on dropping `NonSendResourceData`, if there's a mismatch, panic. Moved all of the checks that `MainThreadValidator` would do into `NonSendResources` instead.

All `!Send` resources now individually track which thread they were inserted from. This is validated against for every access, mutation, and drop that could be done against the value. 

A regression test using an altered version of the example from bevyengine#3310 has been added.

This is a stopgap solution for the current status quo. A full solution may involve fully removing `!Send` resources/components from `World`, which will likely require a much more thorough design on how to handle the existing in-engine and ecosystem use cases.

This PR also introduces another breaking change:

```rust
    use bevy_ecs::prelude::*;

    #[derive(Resource)]
    struct Resource(u32);

    fn main() {
        let mut world = World::new();
        world.insert_resource(Resource(1));
        world.insert_non_send_resource(Resource(2));
        let res = world.get_resource_mut::<Resource>().unwrap();
        assert_eq!(res.0, 2);
    }
```

This code will run correctly on 0.9.1 but not with this PR, since NonSend resources and normal resources have become actual distinct concepts storage wise.

## Changelog
Changed: Fix soundness bug with `World: Send`. Dropping a `World` that contains a `!Send` resource on the wrong thread will now panic.

## Migration Guide
Normal resources and `NonSend` resources no longer share the same backing storage. If `R: Resource`, then `NonSend<R>` and `Res<R>` will return different instances from each other. If you are using both `Res<T>` and `NonSend<T>` (or their mutable variants), to fetch the same resources, it's strongly advised to use `Res<T>`.
alradish pushed a commit to alradish/bevy that referenced this issue Jan 22, 2023
@james7132 @alradish
Panic on dropping NonSend in non-origin thread. (bevyengine#6534)
9f66db7 
# Objective

Fixes bevyengine#3310. Fixes bevyengine#6282. Fixes bevyengine#6278. Fixes bevyengine#3666.

## Solution
Split out `!Send` resources into `NonSendResources`. Add a `origin_thread_id` to all `!Send` Resources, check it on dropping `NonSendResourceData`, if there's a mismatch, panic. Moved all of the checks that `MainThreadValidator` would do into `NonSendResources` instead.

All `!Send` resources now individually track which thread they were inserted from. This is validated against for every access, mutation, and drop that could be done against the value. 

A regression test using an altered version of the example from bevyengine#3310 has been added.

This is a stopgap solution for the current status quo. A full solution may involve fully removing `!Send` resources/components from `World`, which will likely require a much more thorough design on how to handle the existing in-engine and ecosystem use cases.

This PR also introduces another breaking change:

```rust
    use bevy_ecs::prelude::*;

    #[derive(Resource)]
    struct Resource(u32);

    fn main() {
        let mut world = World::new();
        world.insert_resource(Resource(1));
        world.insert_non_send_resource(Resource(2));
        let res = world.get_resource_mut::<Resource>().unwrap();
        assert_eq!(res.0, 2);
    }
```

This code will run correctly on 0.9.1 but not with this PR, since NonSend resources and normal resources have become actual distinct concepts storage wise.

## Changelog
Changed: Fix soundness bug with `World: Send`. Dropping a `World` that contains a `!Send` resource on the wrong thread will now panic.

## Migration Guide
Normal resources and `NonSend` resources no longer share the same backing storage. If `R: Resource`, then `NonSend<R>` and `Res<R>` will return different instances from each other. If you are using both `Res<T>` and `NonSend<T>` (or their mutable variants), to fetch the same resources, it's strongly advised to use `Res<T>`.
ItsDoot pushed a commit to ItsDoot/bevy that referenced this issue Feb 1, 2023
@james7132 @ItsDoot
Extract Resources into their own dedicated storage (bevyengine#4809)
acae887 
# Objective
At least partially addresses bevyengine#6282.

Resources are currently stored as a dedicated Resource archetype (ID 1). This allows for easy code reusability, but unnecessarily adds 72 bytes (on 64-bit systems) to the struct that is only used for that one archetype. It also requires several fields to be `pub(crate)` which isn't ideal.

This should also remove one sparse-set lookup from fetching, inserting, and removing resources from a `World`.

## Solution

- Add `Resources` parallel to `Tables` and `SparseSets` and extract the functionality used by `Archetype` in it.
- Remove `unique_components` from `Archetype`
- Remove the `pub(crate)` on `Archetype::components`.
- Remove `ArchetypeId::RESOURCE`
- Remove `Archetypes::resource` and `Archetypes::resource_mut`

---

## Changelog
Added: `Resources` type to store resources.
Added: `Storages::resource`
Removed: `ArchetypeId::RESOURCE`
Removed: `Archetypes::resource` and `Archetypes::resources`
Removed: `Archetype::unique_components` and `Archetypes::unique_components_mut`

## Migration Guide
Resources have been moved to `Resources` under `Storages` in `World`. All code dependent on `Archetype::unique_components(_mut)` should access it via `world.storages().resources()` instead.

All APIs accessing the raw data of individual resources (mutable *and* read-only) have been removed as these APIs allowed for unsound unsafe code. All usages of these APIs should be changed to use `World::{get, insert, remove}_resource`.
ItsDoot pushed a commit to ItsDoot/bevy that referenced this issue Feb 1, 2023
@james7132 @ItsDoot
Panic on dropping NonSend in non-origin thread. (bevyengine#6534)
55201ae 
# Objective

Fixes bevyengine#3310. Fixes bevyengine#6282. Fixes bevyengine#6278. Fixes bevyengine#3666.

## Solution
Split out `!Send` resources into `NonSendResources`. Add a `origin_thread_id` to all `!Send` Resources, check it on dropping `NonSendResourceData`, if there's a mismatch, panic. Moved all of the checks that `MainThreadValidator` would do into `NonSendResources` instead.

All `!Send` resources now individually track which thread they were inserted from. This is validated against for every access, mutation, and drop that could be done against the value. 

A regression test using an altered version of the example from bevyengine#3310 has been added.

This is a stopgap solution for the current status quo. A full solution may involve fully removing `!Send` resources/components from `World`, which will likely require a much more thorough design on how to handle the existing in-engine and ecosystem use cases.

This PR also introduces another breaking change:

```rust
    use bevy_ecs::prelude::*;

    #[derive(Resource)]
    struct Resource(u32);

    fn main() {
        let mut world = World::new();
        world.insert_resource(Resource(1));
        world.insert_non_send_resource(Resource(2));
        let res = world.get_resource_mut::<Resource>().unwrap();
        assert_eq!(res.0, 2);
    }
```

This code will run correctly on 0.9.1 but not with this PR, since NonSend resources and normal resources have become actual distinct concepts storage wise.

## Changelog
Changed: Fix soundness bug with `World: Send`. Dropping a `World` that contains a `!Send` resource on the wrong thread will now panic.

## Migration Guide
Normal resources and `NonSend` resources no longer share the same backing storage. If `R: Resource`, then `NonSend<R>` and `Res<R>` will return different instances from each other. If you are using both `Res<T>` and `NonSend<T>` (or their mutable variants), to fetch the same resources, it's strongly advised to use `Res<T>`.
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[Merged by Bors] - Panic on dropping NonSend in non-origin thread. james7132/bevy
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