Unexpected SystemInMultipleBaseSets panic due to on_update

[NiklasEi]

Bevy version

main branch a1e4114

What you did

I am trying to order an exclusive system in a pretty standard way for Plugins using states:

1. The system should run early in every frame (before any "normal" user systems)
2. The system should only run in the given state

            .add_system(
                exclusive_system
                    .in_base_set(CoreSet::PreUpdate)
                    .in_set(MySet::Label)
                    .on_update(MyStates::State)

What went wrong

This triggers the unexpected panic SystemInMultipleBaseSets { system: "Some(System exclusive_system: {is_exclusive})", first_set: "StateTransitions", second_set: "PreUpdate" }'

Additional information

• The fact that this is an exclusive system seems irrelevant; the same panic happens with a normal system
• replacing on_update with run_if(state_equals(MyStates::State)) removes the panic, but is the exact behaviour I would have expected from on_update

[lewiszlw]

Agree. Current behaviour is weird, we can't choose to put in which base set when using .on_update(MyStates::State).