bevy/crates/bevy_ptr
James Liu 4cd53cc7e1
Clean up pointer use in BundleSpawner/BundleInserter (#12269)
# Objective
Following #10756, we're now using raw pointers in BundleInserter and
BundleSpawner. This is primarily to get around the need to split the
borrow on the World, but it leaves a lot to be desired in terms of
safety guarantees. There's no type level guarantee the code can't
dereference a null pointer, and it's restoring them to borrows fairly
liberally within the associated functions.

## Solution

* Replace the pointers with `NonNull` and a new `bevy_ptr::ConstNonNull`
that only allows conversion back to read-only borrows
* Remove the closure to avoid potentially aliasing through the closure
by restructuring the match expression.
* Move all conversions back into borrows as far up as possible to ensure
that the borrow checker is at least locally followed.
2024-03-06 05:52:18 +00:00
..
src Clean up pointer use in BundleSpawner/BundleInserter (#12269) 2024-03-06 05:52:18 +00:00
Cargo.toml Bump Version after Release (#12020) 2024-02-21 20:58:59 +00:00
README.md add and fix shields in Readmes (#9993) 2023-10-15 00:52:31 +00:00

Bevy Ptr

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The bevy_ptr crate provides low-level abstractions for working with pointers in a more safe way than using rust's raw pointers.

Rust has lifetimed and typed references (&'a T), unlifetimed and typed references (*const T), but no lifetimed but untyped references. bevy_ptr adds them, called Ptr<'a>, PtrMut<'a> and OwningPtr<'a>. These types are lifetime-checked so can never lead to problems like use-after-frees and must always point to valid data.