Avoid unwraps in winit fullscreen handling code

[Friz64]

Objective

• Get rid of unwraps in winit fullscreen handling code, which are the source of some crashes.
• Fix Wayland panic and crash #11275

Solution

• Replace the unwraps with warnings. Ignore the fullscreen request, do nothing instead.

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[alice-i-cecile]

I'd definitely like to avoid panicking here, but I don't love the nested options in an already dense area of code. Is there another way to express this control flow?

[BD103]

I'd definitely like to avoid panicking here, but I don't love the nested options in an already dense area of code. Is there another way to express this control flow?

I believe this is probably the best it can be. if let is about as concise you can get when matching a single pattern. If there was a method on Result such as result.run_if_err(|| warn!(...)) this could be shortened, but no such function exists in the standard library. (Nor does this warrant creating our own.) It's not pretty, but it's safer handling errors explicitly than panicking.

On the other hand, this line can be shortened to a let else:

bevy/crates/bevy_winit/src/system.rs

Line 124 in e42dacd

if let Some(winit_window) = winit_windows.get_window(entity) {

let Some(winit_window) = winit_windows.get_window(entity) else {
    continue;
};

@Friz64, could you implement that change in your PR?

[Friz64]

@Friz64, could you implement that change in your PR?

Good suggestion, done.

[pablo-lua]

Simplified the code in some areas and avoided the unwrap with warnings, all good!