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# Objective Found while working on #7385. The struct `EntityMut` has the safety invariant that it's cached `EntityLocation` must always accurately specify where the entity is stored. Thus, any time its location might be invalidated (such as by calling `EntityMut::world_mut` and moving archetypes), the cached location *must* be updated by calling `EntityMut::update_location`. The method `world_scope` encapsulates this pattern in safe API by requiring world mutations to be done in a closure, after which `update_location` will automatically be called. However, this method has a soundness hole: if a panic occurs within the closure, then `update_location` will never get called. If the panic is caught in an outer scope, then the `EntityMut` will be left with an outdated location, which is undefined behavior. An example of this can be seen in the unit test `entity_mut_world_scope_panic`, which has been added to this PR as a regression test. Without the other changes in this PR, that test will invoke undefined behavior in safe code. ## Solution Call `EntityMut::update_location()` from within a `Drop` impl, which ensures that it will get executed even if `EntityMut::world_scope` unwinds. |
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| bevy_animation | ||
| bevy_app | ||
| bevy_asset | ||
| bevy_audio | ||
| bevy_core | ||
| bevy_core_pipeline | ||
| bevy_derive | ||
| bevy_diagnostic | ||
| bevy_dylib | ||
| bevy_dynamic_plugin | ||
| bevy_ecs | ||
| bevy_ecs_compile_fail_tests | ||
| bevy_encase_derive | ||
| bevy_gilrs | ||
| bevy_gltf | ||
| bevy_hierarchy | ||
| bevy_input | ||
| bevy_internal | ||
| bevy_log | ||
| bevy_macro_utils | ||
| bevy_math | ||
| bevy_mikktspace | ||
| bevy_pbr | ||
| bevy_ptr | ||
| bevy_reflect | ||
| bevy_reflect_compile_fail_tests | ||
| bevy_render | ||
| bevy_scene | ||
| bevy_sprite | ||
| bevy_tasks | ||
| bevy_text | ||
| bevy_time | ||
| bevy_transform | ||
| bevy_ui | ||
| bevy_utils | ||
| bevy_window | ||
| bevy_winit | ||