When rendering animation without baking dynamics first, rigid body
objects/shapes might be set up for the fist time (see
`rigidbody_update_simulation`).
Here is my take on what happens when we run into the reported crash:
In `rigidbody_validate_sim_object`, `rigidbody_validate_sim_shape` can
be called (which -- amongst other things -- can call `RB_shape_delete`).
It does not set `RBO_FLAG_NEEDS_RESHAPE` nor calls
`RB_body_set_collision_shape`. It only sets `rbo->shared->physics_shape`
(which only seems to to update the "blender side of things", but not the
"bullet side of things").
Then later (still in `rigidbody_validate_sim_object`),
`RB_dworld_add_body`/ `btDiscreteDynamicsWorld::addRigidBody`>
`btCollisionWorld::addCollisionObject` > collisionObject->getCollisionShape()
is called, but confused because we called `RB_shape_delete` before.
Also see the TODO(Sybren) comment from 98a0bcd425 (which might even be
removed with this PR, but not I havent verified "collision shape being
created twice" is now not happening anymore).
One might think that flagging `RBO_FLAG_NEEDS_RESHAPE` might be enough,
but reacting on that only happens later in `rigidbody_update_simulation`
(so not early enough to not run into the issues of `RB_dworld_add_body`
above).
So to resolve, call `RB_body_set_collision_shape` in
`rigidbody_validate_sim_shape` if we actually made a new one.
Fixes#130991
Pull Request: https://projects.blender.org/blender/blender/pulls/131039
566a38ffee