Fix unsoundness in QueryState::is_empty
#9463
Merged
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Objective
QueryState::is_empty
is unsound, as it does not validate the world. If a mismatched world is passed in, then the query filter may cast a component to an incorrect type, causing undefined behavior.Solution
Add world validation. To prevent a performance regression in
Query
(whose world does not need to be validated), the unchecked functionis_empty_unsafe_world_cell
has been added. This also allows us to remove one of the last usages of the private functionUnsafeWorldCell::unsafe_world
, which takes us a step towards being able to remove that method entirely.