Objective

The init_physics_transform hook can fail for scenes, because hierarchies may not be finalized in hooks (see bevyengine/bevy#18671). This normally doesn't actually cause problems, but in a very specific case where an entity has both a RigidBody and Collider (causing init_physics_transform to be called twice) in a hierarchy, and the insertion of one of the components is deferred such that the hierarchy is finalized for that one but not the other, the computed global transforms will end up being wrong. Yeah.

Solution

For now, just avoid calling init_physics_transform twice by checking if the entity has a RigidBody for colliders.

Additionally, only run transform_to_position logic for Position and Rotation if they were not just added, to avoid using the invalid values. Propagation will fix things up later.

Testing

The physics_avian example from bevy_trenchbroom, adding a RigidBody for the brushes.