Observers causes a panic in scenes

[s-puig]

Bevy version

e155fe1

What you did

Create a simple scene with an observer.

What went wrong

Scene spawn system causes a crash caused by the observer.

Additional information

Observers are a component that doesn't implement Reflect, thus causing the crash.

PS: Scene spawning should never cause a crash in the first place, either building the scene should be fallible or the scene spawning ignored with a warning.

[BenjaminBrienen]

Do you have a preferred solution? Maybe Observer implementing Reflect, or is the build-time failure optimal?

[s-puig]

Do you have a preferred solution? Maybe Observer implementing Reflect, or is the build-time failure optimal?

I think its three different issues:

• Observers need to implement Reflect or the use-case for scenes becomes very limited.
• Building scenes should be a fallible method. Right now it doesn't seem to check anything, it only stores a world.
• Avoid panicking at all costs. If scene spawning goes wrong it should send a warning and/or event so it can be handled.