# Objective
A `RawWindowHandle` is only valid as long as the window it was retrieved
from is alive. Extend the lifetime of the window, so that the
`RawWindowHandle` doesn't outlive it, and bevy doesn't crash when
closing a window a pipelined renderer is drawing to.
- Fix#11236
- Fix#11150
- Fix#11734
- Alternative to / Closes#12524
## Solution
Introduce a `WindowWrapper` that takes ownership of the window. Require
it to be used when constructing a `RawHandleWrapper`. This forces
windowing backends to store their window in this wrapper.
The `WindowWrapper` is implemented by storing the window in an `Arc<dyn
Any + Send + Sync>`.
We use dynamic dispatch here because we later want the
`RawHandleWrapper` to be able dynamically hold a reference to any
windowing backend's window.
But alas, the `WindowWrapper` itself is still practically invisible to
windowing backends, because it implements `Deref` to the underlying
window, by storing its type in a `PhantomData`.
---
## Changelog
### Added
- Added `WindowWrapper`, which windowing backends are now required to
use to store their underlying window.
### Fixed
- Fixed a safety problem which caused crashes when closing bevy windows
when using pipelined rendering.
## Migration Guide
- Windowing backends now need to store their window in the new
`WindowWrapper`.
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