Fix bevymark crash

[opstic]

Objective

Fixes #7403

Solution

• Replace windows.single() with windows.get_single()? then use system piping to return early.

[alice-i-cecile]

I would use if let Some(window) instead here: it's generally clearer IMO.

[alice-i-cecile]

You could also use the new pipe adaptors and ?: I'd be happy with either option.

[opstic]

@alice-i-cecile Done, it's now using if let to set the window variable.

[alice-i-cecile]

Ah: I meant to wrap the entire block below that relies on window existing into the if let statement :)

In rust, I would use the ? operator (and return a Result) to convey that early return pattern more idiomatically.

[opstic]

@alice-i-cecile Done, now it's using system piping.

[alice-i-cecile]

Very nice! It's good to demo this pattern in more examples too.

[mockersf]

That should not happen, the system you fixed is in stage Update and getting the window in that stage should not panic (unless the developer willingly made a way to not have windows). Ignoring that failure is not the right fix, we should find the root cause. Maybe an interaction with the fact that the system is in a time step.

I would wait for the new scheduler PR (#7267) to be merged (which changes a lot of that), and then try to reproduce the crash with it, and if that's still present try to find the root cause

[opstic]

Alright, so should I close this?

[alice-i-cecile]

Yeah, let's close this out for now and leave the issue open :)