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fix(D.2b): harden optimistic-move pending map (Opus review I1+I2)

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I2 (real bug): Clear() (teleport/logoff) and Remove() (item destroyed) now drop
the item's _pendingMoves entry — a stale snapshot on a recycled guid could
otherwise mis-rollback a different future item.
I1 (race): track an OUTSTANDING count per item so an early ConfirmMove (0x0022)
for the first of several in-flight moves of the SAME item can't clear the
snapshot while a later move is unconfirmed — a later reject can still roll back
to the original instead of stranding the item at the rejected position.
Both with regression tests; full suite green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
This commit is contained in:
Erik 2026-06-22 20:12:54 +02:00
parent 8df395894e
commit 975f89c870
2 changed files with 49 additions and 8 deletions
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31
src/AcDream.Core/Items/ClientObjectTable.cs
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@ -47,7 +47,7 @@ public sealed class ClientObjectTable
// B-Drag: pre-move snapshots for optimistic inventory moves. itemId → (container, slot) BEFORE
// the optimistic MoveItem; restored by RollbackMove on InventoryServerSaveFailed (0x00A0),
// cleared by ConfirmMove on the InventoryPutObjInContainer (0x0022) echo.
private readonly Dictionary<uint, (uint container, int slot)> _pendingMoves = new();
private readonly Dictionary<uint, (uint container, int slot, int outstanding)> _pendingMoves = new();
/// <summary>Fires when an object is first added to the session.</summary>
public event Action<ClientObject>? ObjectAdded;
@ -144,17 +144,30 @@ public sealed class ClientObjectTable
public bool MoveItemOptimistic(uint itemId, uint newContainerId, int newSlot)
{
if (!_objects.TryGetValue(itemId, out var item)) return false;
if (!_pendingMoves.ContainsKey(itemId))
_pendingMoves[itemId] = (item.ContainerId, item.ContainerSlot); // snapshot the ORIGINAL once
// Snapshot the ORIGINAL position once + count OUTSTANDING optimistic moves of this item. The
// count stops an early confirm (0x0022) for the first of several in-flight moves of the SAME
// item from clearing the snapshot while a later move is still unconfirmed — else a later
// reject would find nothing pending and strand the item at the rejected position.
if (_pendingMoves.TryGetValue(itemId, out var p))
_pendingMoves[itemId] = (p.container, p.slot, p.outstanding + 1);
else
_pendingMoves[itemId] = (item.ContainerId, item.ContainerSlot, 1);
return MoveItem(itemId, newContainerId, newSlot);
}
/// <summary>The server confirmed the move (InventoryPutObjInContainer 0x0022 echo) — drop the
/// pending snapshot. No-op for a server-initiated move we never tracked.</summary>
public void ConfirmMove(uint itemId) => _pendingMoves.Remove(itemId);
/// <summary>The server confirmed a move (InventoryPutObjInContainer 0x0022 echo) — decrement the
/// outstanding count; drop the snapshot only once no optimistic moves of this item remain. No-op
/// for a server-initiated move we never tracked.</summary>
public void ConfirmMove(uint itemId)
{
if (!_pendingMoves.TryGetValue(itemId, out var p)) return;
if (p.outstanding <= 1) _pendingMoves.Remove(itemId);
else _pendingMoves[itemId] = (p.container, p.slot, p.outstanding - 1);
}
/// <summary>The server rejected the move (InventoryServerSaveFailed 0x00A0) — restore the item to
/// its pre-move (container, slot) and drop the snapshot. False if nothing was pending.</summary>
/// <summary>The server rejected a move (InventoryServerSaveFailed 0x00A0) — restore the item to its
/// pre-move (container, slot) and drop the snapshot entirely (the server's next snapshot reconciles
/// any still-outstanding moves). False if nothing was pending.</summary>
public bool RollbackMove(uint itemId)
{
if (!_pendingMoves.TryGetValue(itemId, out var pre)) return false;
@ -171,6 +184,7 @@ public sealed class ClientObjectTable
if (!_objects.TryRemove(itemId, out var item)) return false;
if (item.ContainerId != 0 && _containerIndex.TryGetValue(item.ContainerId, out var l))
l.Remove(itemId);
_pendingMoves.Remove(itemId); // a destroyed item must not leave a snapshot that mis-rolls-back a recycled guid
ObjectRemoved?.Invoke(item);
return true;
}
@ -430,5 +444,6 @@ public sealed class ClientObjectTable
_objects.Clear();
_containers.Clear();
_containerIndex.Clear();
_pendingMoves.Clear(); // B-Drag: drop in-flight optimistic snapshots (a recycled guid must not mis-rollback)
}
}