Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

[Merged by Bors] - Implement Clone for Fetches #2641

Closed
wants to merge 4 commits into from
Closed

[Merged by Bors] - Implement Clone for Fetches #2641

wants to merge 4 commits into from

Conversation

msvbg
Copy link
Contributor

@msvbg msvbg commented Aug 12, 2021 •
edited
Loading

Objective

This:

use bevy::prelude::*;

fn main() {
    App::new()
    .add_system(test)
    .run();
}

fn test(entities: Query<Entity>) {
    let mut combinations = entities.iter_combinations_mut();
    while let Some([e1, e2]) = combinations.fetch_next() {    
        dbg!(e1);
    }
}

fails with the message "the trait bound bevy::ecs::query::EntityFetch: std::clone::Clone is not satisfied".

Solution

It works after adding the naive clone implementation to EntityFetch. I'm not super familiar with ECS internals, so I'd appreciate input on this.

@github-actions github-actions bot added the S-Needs-Triage This issue needs to be labelled label Aug 12, 2021
@alice-i-cecile alice-i-cecile added A-ECS Entities, components, systems, and events C-Bug An unexpected or incorrect behavior E-Help-Wanted and removed S-Needs-Triage This issue needs to be labelled labels Aug 12, 2021
@alice-i-cecile
Copy link
Member

Since the access in EntityFetch is read-only, this should be safe. I don't think we've had any use for this before, but your example should definitely be supported.

@msvbg
Copy link
Contributor Author

msvbg commented Aug 12, 2021 •
edited
Loading

OptionFetch fails similarly, so I added an implementation for that and for ChangeTrackersFetch for good measure.

@msvbg msvbg changed the title Implement Clone for EntityFetch Implement Clone for Fetches Aug 12, 2021
cart
cart approved these changes Aug 13, 2021
View reviewed changes
Copy link
Member

@cart cart left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Nice catch! This is all safe. We could merge this as-is, but theres one place to improve flexibility (see comment).

crates/bevy_ecs/src/query/fetch.rs Outdated Show resolved Hide resolved
@cart
Copy link
Member

cart commented Aug 13, 2021

bors r+

bors bot pushed a commit that referenced this pull request Aug 13, 2021
@msvbg
Implement Clone for Fetches (#2641)
a21e646 
# Objective

This:

```rust
use bevy::prelude::*;

fn main() {
    App::new()
    .add_system(test)
    .run();
}

fn test(entities: Query<Entity>) {
    let mut combinations = entities.iter_combinations_mut();
    while let Some([e1, e2]) = combinations.fetch_next() {    
        dbg!(e1);
    }
}
```

fails with the message "the trait bound `bevy::ecs::query::EntityFetch: std::clone::Clone` is not satisfied". 


## Solution

It works after adding the naive clone implementation to EntityFetch. I'm not super familiar with ECS internals, so I'd appreciate input on this.
@bors
Copy link
Contributor

bors bot commented Aug 13, 2021

Build failed:

@cart
Copy link
Member

cart commented Aug 14, 2021

bors r+

bors bot pushed a commit that referenced this pull request Aug 14, 2021
@msvbg
Implement Clone for Fetches (#2641)
96f0e02 
# Objective

This:

```rust
use bevy::prelude::*;

fn main() {
    App::new()
    .add_system(test)
    .run();
}

fn test(entities: Query<Entity>) {
    let mut combinations = entities.iter_combinations_mut();
    while let Some([e1, e2]) = combinations.fetch_next() {    
        dbg!(e1);
    }
}
```

fails with the message "the trait bound `bevy::ecs::query::EntityFetch: std::clone::Clone` is not satisfied". 


## Solution

It works after adding the naive clone implementation to EntityFetch. I'm not super familiar with ECS internals, so I'd appreciate input on this.
@bors
Copy link
Contributor

bors bot commented Aug 14, 2021

Pull request successfully merged into main.

Build succeeded:

@bors bors bot changed the title Implement Clone for Fetches [Merged by Bors] - Implement Clone for Fetches Aug 14, 2021
@bors bors bot closed this Aug 14, 2021
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Reviewers

@cart cart cart approved these changes

Assignees
No one assigned
Labels
A-ECS Entities, components, systems, and events C-Bug An unexpected or incorrect behavior
Projects
None yet
Milestone
No milestone
Development

Successfully merging this pull request may close these issues.
3 participants
@msvbg @alice-i-cecile @cart