MP task #47: DISPROVE the Entity-layout root cause; correct the record

The prior commit (c78662a) filed cross-pod damage failure under a
"cross-TU Entity/EntityID layout divergence" (and the P5 base-region
audit). A compile-time offsetof probe injected into BOTH translation
units disproves that: game/reconstructed AND engine/MUNGA compute an
IDENTICAL Entity layout --

  sizeof(Entity)=444  offsetof(entityID)=380 (0x17C)
  offsetof(ownerID)=388  offsetof(simulationFlags)=32
  offsetof(Mech,entityID)=380  (Entity subobject at 0)

So Entity::Dispatch reads this->entityID at the SAME offset mech4's
GetEntityID() does -- there is no per-TU read difference, and the
logged 3:22 (mech4 candidate) vs 3:19 (engine Dispatch) cannot be one
object read two ways. Those lines were different objects/messages,
mis-correlated. The distinct, REAL P5 "base-region layout divergence"
(HARD_PROBLEMS.md) is about raw-offset stomps at this+0x2d4..0x2f0 --
far above entityID -- and is unrelated to #47.

Changes:
- Revert the committed BT_MP_NET engine diagnostics (ENTITY/EVENT/
  NTTMGR/RECEIVER/L4NET) to the clean a9c3e96 baseline -- those are
  the very instruments that produced the mis-correlated data.
- mech4 BT_MP_FORCE_DMG hook: dispatch via the real m->Dispatch(&td)
  path (no false id stamping); comment records the offsetof finding.
- context/multiplayer.md: layout-divergence RULED OUT; 3:22/3:19 marked
  unconfirmed; leading hypotheses reframed as H2 (wire host-relative
  (de)serialization) vs H3 (replicant id != master's registered key),
  to be distinguished by a 2-node run with per-message correlation.

Solo un-regressed (mech walks + targets, 0 faults). Cross-pod delivery
remains open, but the investigation is redirected off the wrong (large,
structural) layout-audit path onto the EntityID wire/id-assignment path.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

This commit is contained in:

arcattack

2026-07-09 12:09:50 -05:00

co-authored by

Claude Fable 5

parent c78662a0f1

commit 04a2049ce2

7 changed files with 55 additions and 75 deletions

									
										engine/MUNGA/RECEIVER.cpp
									
		-6
	
												View File
												
				@@ -98,12 +98,6 @@ void

					//

					Receiver::SharedData *sharedData = GetSharedData();

					Handler handler = sharedData->activeMessageHandlers->Find(what->messageID);

					// MP DIAGNOSTIC (task #47): for a TakeDamage (msgID 21), report whether a

					// handler is found on this receiver (the cross-pod delivery endpoint).

					if (what->messageID == 21 && getenv("BT_MP_NET"))

						DEBUG_STREAM << "[mp-recv2] Receive TakeDamage this=" << (void*)this

							<< " handler=" << (handler != Receiver::NullHandler ? "FOUND" : "NULL")

							<< "\n" << std::flush;

					if (handler != Receiver::NullHandler)

					{

						(this->*handler)(what);