Systems that are reported ambiguous seem to run deterministically | Bevy | Page 1

tall pendant May 14, 2024, 7:48 AM

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I am following the Getting Started tutorial in the bevy book (https://bevyengine.org/learn/quick-start/getting-started/ecs/). At this point, there are two systems using the Name component, and I have not yet called chain() on them, so they should be running non-deterministically.
My code is like this: add_systems(Update, (greet_people, update_people))
(fyi, if you can't be bothered to open the link, both systems access the same component, one mutably and the other immutably.)

However, they seem to always run in the same order, and it also seems to depend on the order I have written them down. I have turned on ambiguity detection and it does report the ambiguity, it just never seems to happen from the printlns. Why is that?

craggy pagoda May 14, 2024, 7:51 AM

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the ambiguity exists because bevy does not guarantee that this happens. So as you add more systems, it might randomly stop working.

tall pendant May 14, 2024, 7:52 AM

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ohh so it is more or less expected to run in the written order for something simple?

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thanks a lot by the way!

craggy pagoda May 14, 2024, 7:59 AM

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tall pendant ohh so it is more or less expected to run in the written order for something sim...

mostly yes, but its not reliable and you will shoot yourself in the foot if you try to rely on it

#Systems that are reported ambiguous seem to run deterministically