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feat(physics): C4 route 4b-3 — remote teleport + cell-less through the canonical placement

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Flips the last remote classification (SetPosition: teleport-advanced and
cell-less) onto 4b-1's RuntimeRemotePlacementDriveController, runs retail's
teleport_hook before the placement, and deletes the legacy remote-teleport
machinery. Contract: docs/research/2026-08-04-c4-route-4b-3-contract.md.

Retail: MoveOrTeleport @0x00516330's branch @0x00516386 -> teleport_hook
@0x005163EF -> SetFlags(0x1012) @0x00516414 -> SetPosition @0x00516420 ->
return 1 @0x00516438. The hook @0x00514ED0 runs BEFORE the placement and
regardless of its outcome. Retail places this branch unconditionally, at any
distance and any contact state (arg4 is read only @0x0051638E, after the
branch) — which is what retires AP-137's cell-less enqueue-vs-place delta.

D1 — the classifier's cell-less input is now the PRE-merge committed cell.
Retail's predicate is `this_1->cell == 0`, the BODY's own cell at
MoveOrTeleport entry (this_1 is assigned from this @0x00516334). acdream fed
the POST-merge canonical.FullCellId, which RefreshSnapshot ->
RefreshDerivedState -> SetFullCell has already stamped with the accepted wire
cell; a zero wire cell fails validation into RejectedData first. The shipped
remote cell-less predicate was therefore dead code, not merely different from
remotePlacementRequired. Threaded via a builder overload; route 1's overload
is untouched. The graphical !IsSpatiallyVisible arm of
projectionRequiresTeleportHook is deleted — a presentation predicate with no
retail analogue that fired the teleport machinery on a routine hot path.

Deleted: RemoteTeleportController (605), RemoteTeleportPlacement (85),
RemoteShadowPlacementSynchronizer (49), their 1,709 lines of tests, the
remotePlacementRequired predicate, the TeleportHookRequired plumbing, the
legacy pre-operation ConstrainTo fallback, and the player arm's legacy
!IsGrounded fallback. Net -2,030 lines.

Structural fix (two independent Opus reviews, round 1 FAIL/FAIL): three of the
four MAJORs were one defect — OnPosition carried two parallel inline copies of
the routing tail (player-guid, NPC-guid) that had drifted. Extracted
RunRemoteArmTail (3 call sites) and ApplyWireAirborneLeftoverBookkeeping (2),
both branches now share one implementation.

  A1  ToConstraintArm mapped AirborneSnap -> AirborneNoOperation, so the NPC
      arm armed ConstrainTo ZERO times for an out-of-contact wire-grounded
      creature — a regression this slice introduced while closing a
      structurally identical hole. Now maps to NearInterpolate; switch made
      total with a throwing default proven unreachable.
  R1  D2's write-nothing shape existed on the player arm only; NPC packets
      fell through and wrote the body. Retail makes no player/NPC distinction.
  R2  report_collision_end(this,1) @0x00514F31 was bound to
      ShadowObjects.Suspend, a port of a DIFFERENT retail function
      (remove_shadows_from_cells) that teleport_hook never calls. Now routes
      to RuntimeCollisionReportingState.LeaveWorld, which wraps the private
      ForceEnd in an admission-blocking transaction so a DoCollisionEnd
      callback cannot recreate the contact table.
  R3/A2 A teleported NPC synthesized ServerVelocity from the teleport distance
      (~1,000+ m/s) and planned a run cycle from it. Both the install and
      RemoteServerControlledVelocityCycle.Apply now gate on !isTeleportRoute.

BISECT HAZARD — A1's fix is correct only BECAUSE R1 landed. AirborneSnap is
reachable wire-airborne on the NPC arm only while D2's shape is missing there.
Reverting R1 alone silently inverts A1 into the opposite divergence: arming
where retail returns 0. Revert both or neither.

Also in the velocity hunk: the NPC block's two !IsPlayerGuid(update.Guid)
guards were dropped when it was wrapped in `if (!isTeleportRoute)`. Safe — all
five exit paths of the enclosing IsPlayerGuid block return, so the predicate is
unconditionally false below it — but it was unremarked by both reviews.

Register: AP-137 REWRITTEN (not deleted) to the surviving acdream-only
divergences — null classification during the login window and Rejected*
through UnroutedCatchUp keep a row. AD-42's RemoteTeleportController citation
retired; AP-136/AP-138 writer lists corrected to the two surviving non-Position
rebucket writers; AP-138 gains the teleport arm as a second producer of the
visible-without-collision residual (retirement path remains #309). AP-135 is
untouched and its two airborne bookkeeping writes are preserved on both arms.
AP-131 does not retire; #276 does not close.

Proof obligation 1: ParkCollisionResidents' overlap throw stays unreachable —
the teleport arm adds packets to the same TryBeginExclusiveAuthoredPlacement
one-operation-per-key machinery the far arm uses, opens no new operation shape,
and every DeferredCell outcome cancels synchronously with
restoreCancelledPark: true. The guarded property remains
HasOldPrefixPlacementDebt's stall, not a throw (4b-1's B2 caveat stands).

Correction to an earlier claim: LiveEntityPresentationController's
_activePlacementOwners was NOT write-never at HEAD —
remotePlacementRequired -> BeginPlacement -> Begin -> BeginAuthoritativePlacement
was a live writer chain. It becomes write-never BECAUSE this slice deletes that
chain, which is why deleting the dead half is behaviour-preserving.

Probe: ACDREAM_PROBE_REMOTE_TELEPORT=1 emits one [remote-teleport] line per
routed arm (guid, cause, hook-ran, placement status). TEMPORARY, strip with the
probe family.

Carried, disclosed not fixed: no dedicated bidirectional collision-partner test
for R2 (the wiring, not LeaveWorld itself, is what lacks coverage); the
stress test's teleport step drives hand-written field assignments rather than
the canonical arm; the per-packet runTeleportHook closure allocation (network
path, not the resolve path Slice I's 0 B discipline governs — file before
route 5 adds a fourth call site). B2: IRuntimeCollisionReportObserver has zero
production implementations, so retail's bidirectional DoCollisionEnd half still
reaches no gameplay consumer — this fix closes the wrong-function binding, not
that nobody listens.

Complete Release suite MEASURED at 11,013 passed / 4 skipped / 0 failed
(baseline 11,027/4/0; net -14 = ~33 deleted test cases against ~19 added).
Neither known flake fired (#302 PortalProjectionTests GC-allocation, #308
NakEmissionTests wall-clock).

STILL OWED: the two-client connected gate, which MUST use an NPC/creature
teleport target. Both round-1 MAJORs lived on the NPC arm and the velocity
cycle early-returns for 0x50xxxxxx guids, so a player target structurally
cannot observe A1, A2, or R3.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
This commit is contained in:
Erik 2026-08-04 16:00:10 +02:00
parent 3e002993dd
commit 6dc7ba51ee
53 changed files with 2980 additions and 3372 deletions
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67
src/AcDream.Runtime/Physics/RuntimeRemoteSteadyStatePosition.cs
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@ -196,7 +196,7 @@ internal static class RuntimeRemoteSteadyStatePosition
}
/// <summary>
/// D2: retail arms <c>CPhysicsObj::ConstrainTo</c> strictly AFTER
/// D2/D4: retail arms <c>CPhysicsObj::ConstrainTo</c> strictly AFTER
/// <c>MoveOrTeleport</c> returns nonzero, anchored to the object's own
/// CURRENT (i.e. post-move) position — <c>SmartBox::HandleReceivedPosition</c>
/// 0x00453FD0 reads <c>&amp;arg2-&gt;m_position</c> at 0x00454272, inside
@ -204,38 +204,55 @@ internal static class RuntimeRemoteSteadyStatePosition
/// does NOT run on the airborne no-op.
///
/// <para>
/// Route-gated by
/// <see cref="RuntimeRemoteFarSnapPosition.OwnsAfterOperationConstraint"/>
/// — route 4a's two dispositions plus (C4 route 4b-2) the far snap. Every
/// other classification still arms the leash through the legacy
/// pre-operation call site, unchanged, until 4b-3 moves them too. The
/// legacy site reads the SAME predicate, so no classification can be
/// armed twice or left unarmed.
/// </para>
///
/// <para>
/// This deliberately does not consult the outcome of the operation it
/// follows. Retail's far branch returns 1 @0x005163E8 unconditionally —
/// <c>MoveOrTeleport</c> discards <c>SetPositionSimple</c>'s
/// <c>enum SetPositionError</c> return entirely — so
/// <c>HandleReceivedPosition</c> arms the leash even when the placement
/// FAILED. "Arm only on commit" is the natural misreading and is the same
/// shape as the already-recorded unarmed-leash bug.
/// C4 route 4b-3 (D4): this is now the ONLY arming site — the legacy
/// pre-operation call is deleted, matching retail's single
/// @0x00454272. <paramref name="arm"/> is the routing outcome (which arm
/// actually claimed the packet), NOT the raw classification, because
/// that is the only input that correctly distinguishes a GROUNDED
/// <see cref="RuntimeRemoteAcceptedPositionArm.UnroutedCatchUp"/> (arms —
/// retail has no state here, but the analogue of "MoveOrTeleport returned
/// nonzero" is true) from the wire-airborne leftover shape (D2's
/// return-0 replacement, which never reaches this call at all — see the
/// caller). The complete partition:
/// </para>
/// <list type="bullet">
/// <item><description><see cref="RuntimeRemoteAcceptedPositionArm.TeleportPlacement"/>
/// — arms on EVERY placement outcome (retail discards
/// <c>SetPosition</c>'s error and returns 1 unconditionally
/// @0x00516438).</description></item>
/// <item><description><see cref="RuntimeRemoteAcceptedPositionArm.FarSnapPlacement"/>
/// — arms unconditionally, same reason
/// (@0x005163E8).</description></item>
/// <item><description><see cref="RuntimeRemoteAcceptedPositionArm.NearInterpolate"/>
/// — arms; retail's InterpolateTo branch returns 1
/// (@0x005163BE).</description></item>
/// <item><description><see cref="RuntimeRemoteAcceptedPositionArm.UnroutedCatchUp"/>
/// — arms; only reachable here when the body is already known to be in
/// contact (the caller's free-flight carve-out already
/// returned).</description></item>
/// <item><description><see cref="RuntimeRemoteAcceptedPositionArm.AirborneNoOperation"/>
/// — never arms; retail's <c>arg4 == 0</c> branch returns 0
/// (@0x0051636D). Both production callers already early-return on this
/// classification before reaching any arming call, so this case is
/// defensive.</description></item>
/// </list>
/// </summary>
internal static bool TryArmConstraintAfterOperation(
RuntimeAuthoritativePositionRoute? route,
RuntimeRemoteAcceptedPositionArm arm,
RemoteMotion remote)
{
ArgumentNullException.ThrowIfNull(remote);
if (route is not { } selected
|| !RuntimeRemoteFarSnapPosition.OwnsAfterOperationConstraint(
selected)
|| !selected.ConstrainAfterRouting
|| remote.Host is not { } host)
bool arms = arm switch
{
RuntimeRemoteAcceptedPositionArm.TeleportPlacement => true,
RuntimeRemoteAcceptedPositionArm.FarSnapPlacement => true,
RuntimeRemoteAcceptedPositionArm.NearInterpolate => true,
RuntimeRemoteAcceptedPositionArm.UnroutedCatchUp => true,
RuntimeRemoteAcceptedPositionArm.AirborneNoOperation => false,
_ => false,
};
if (!arms || remote.Host is not { } host)
return false;
}
ArmConstraintAfterOperation(host);
return true;