Root cause (pinned by the worktree investigation + verified against
source): CMotionInterp's dispatch tails strip link animations for
DETACHED objects only (retail `if (physics_obj->cell == 0)
RemoveLinkAnimations`, raw @305627, three ported sites:
DoInterpretedMotion / StopInterpretedMotion / StopCompletely). The R3
port proxied retail's cell pointer with CellPosition.ObjCellId == 0 -
but that #145 field is seeded ONLY by SnapToCell, whose single
production caller is the LOCAL PLAYER's SetPosition. Every REMOTE body
therefore read "detached" forever, and every dispatch stripped the
transition link the motion table had just appended: a used door's
swing link died the same tick (pose snapped closed<->open - the live
symptom), and remote walk<->run link poses have been silently eaten
since the guard landed (masked: locomotion cycles resemble each other;
a door's two poses don't). The dispatcher itself (GetObjectSequence
link path) was verified retail-verbatim end-to-end - not the bug.
Fix: PhysicsBody.InWorld - an explicit "placed in the world" flag
carrying exactly the guard's retail meaning (register row TS-40,
replacing the previously UNREGISTERED ObjCellId proxy). Set by
SnapToCell (retail: enter_world/set_cell assigns the cell) and by
RemoteMotion construction (a RemoteMotion exists only for a world
entity). All three guard sites now test !InWorld. Default false =
retail's pre-enter_world detached state, preserving the guard for
genuinely unplaced bodies (bare-harness interps unchanged).
Tests: InWorldLinkGuardTests pins the polarity at all guard classes
(in-world dispatch keeps links; detached strips; StopCompletely same).
Full suite green: 3,961.
If the door still snaps after this, the open question is DATA (does
the door's table author an On<->Off link at all) - next step per the
investigation: dump the real table's Links/StyleDefaults via a
DoorSetupGfxObjInspectionTests extension.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
350fb5e3a5