From 109f1f990bc74da5dad8b9c250274f8a13be0a3f Mon Sep 17 00:00:00 2001
From: Andrewkydev <grusha.belaev@gmail.com>
Date: Wed, 25 Feb 2026 21:22:45 +0300
Subject: [PATCH] sync latest item entries for runtime-id remap stability

---
 legacyver/item_translator.go | 10 ++++++++++
 legacyver/protocol.go        | 24 ++++++++++++++++++++----
 mapping/item.go              | 24 ++++++++++++++++++++++++
 3 files changed, 54 insertions(+), 4 deletions(-)

diff --git a/legacyver/item_translator.go b/legacyver/item_translator.go
index 2062e56..fe50a59 100644
--- a/legacyver/item_translator.go
+++ b/legacyver/item_translator.go
@@ -63,6 +63,16 @@ type DefaultItemTranslator struct {
 	infoUpdateRID int32
 }
 
+func (t *DefaultItemTranslator) SyncLatestEntries(entries []protocol.ItemEntry) {
+	for _, entry := range entries {
+		version := uint8(protocol.ItemEntryVersionDataDriven)
+		if entry.Version >= 0 && entry.Version <= 255 {
+			version = uint8(entry.Version)
+		}
+		t.latest.UpsertEntryRID(entry.Name, int32(entry.RuntimeID), version, entry.Data)
+	}
+}
+
 func NewItemTranslator(mapping mapping.Item, latestMapping mapping.Item, blockMapping mapping.Block, blockMappingLatest mapping.Block) *DefaultItemTranslator {
 	infoUpdateRID, _ := mapping.ItemNameToRuntimeID("minecraft:info_update")
 	return &DefaultItemTranslator{mapping: mapping, latest: latestMapping, blockMapping: blockMapping, blockMappingLatest: blockMappingLatest,
diff --git a/legacyver/protocol.go b/legacyver/protocol.go
index 9533619..a44a2b6 100644
--- a/legacyver/protocol.go
+++ b/legacyver/protocol.go
@@ -193,6 +193,18 @@ func (p *Protocol) ConvertFromLatest(pk packet.Packet, conn *minecraft.Conn) []p
 }
 
 func (p *Protocol) downgradePackets(pks []packet.Packet, conn *minecraft.Conn) []packet.Packet {
+	if it, ok := p.itemTranslator.(*DefaultItemTranslator); ok {
+		if len(p.Items) > 0 {
+			it.SyncLatestEntries(p.Items)
+		}
+		if conn != nil {
+			gameItems := conn.GameData().Items
+			if len(gameItems) > 0 {
+				it.SyncLatestEntries(gameItems)
+			}
+		}
+	}
+
 	translator, ok := p.blockTranslator.(*DefaultBlockTranslator)
 	if !ok {
 		return pks
@@ -202,7 +214,7 @@ func (p *Protocol) downgradePackets(pks []packet.Packet, conn *minecraft.Conn) [
 		case *packet.DimensionData:
 			translator.dimensionDefinitions = pk.Definitions
 		case *packet.ClientCacheStatus:
-			// pk.Enabled = false // TODO: enable when chunk translation is not broken
+			//pk.Enabled = false // TODO: enable when chunk translation is not broken
 		case *packet.SetActorMotion:
 			pks[pkIndex] = &legacypacket.SetActorMotion{
 				EntityRuntimeID: pk.EntityRuntimeID,
@@ -534,8 +546,12 @@ func (p *Protocol) downgradePackets(pks []packet.Packet, conn *minecraft.Conn) [
 			pk.GameVersion = p.ver
 			pk.BaseGameVersion = p.ver
 
-			items := make([]proto.LegacyItemRegistryEntry, len(p.Items))
-			for i, it := range p.Items {
+			sourceItems := p.Items
+			if len(sourceItems) == 0 && conn != nil {
+				sourceItems = conn.GameData().Items
+			}
+			items := make([]proto.LegacyItemRegistryEntry, len(sourceItems))
+			for i, it := range sourceItems {
 				items[i] = (&proto.LegacyItemRegistryEntry{}).FromLatest(it)
 			}
 
@@ -844,7 +860,7 @@ func (p *Protocol) upgradePackets(pks []packet.Packet, conn *minecraft.Conn) []p
 	for pkIndex, pk := range pks {
 		switch pk := pk.(type) {
 		case *packet.ClientCacheStatus:
-			// pk.Enabled = false // TODO: enable when chunk translation is not broken
+			pk.Enabled = false
 		case *legacypacket.SetActorMotion:
 			pks[pkIndex] = &packet.SetActorMotion{
 				EntityRuntimeID: pk.EntityRuntimeID,
diff --git a/mapping/item.go b/mapping/item.go
index ffdcac6..81f8539 100644
--- a/mapping/item.go
+++ b/mapping/item.go
@@ -19,6 +19,7 @@ type Item interface {
 	ItemRuntimeIDToData(int32) (map[string]any, bool)
 	RegisterEntry(string) int32
 	RegisterEntryRID(string, int32, uint8, map[string]any)
+	UpsertEntryRID(string, int32, uint8, map[string]any)
 	Air() int32
 	ItemVersion() uint16
 	ItemEntries() []ItemEntry
@@ -159,6 +160,29 @@ func (m *DefaultItemMapping) RegisterEntryRID(name string, rid int32, version ui
 	}
 }
 
+func (m *DefaultItemMapping) UpsertEntryRID(name string, rid int32, version uint8, data map[string]any) {
+	defer m.mu.Unlock()
+	m.mu.Lock()
+
+	if oldRID, ok := m.itemNamesToRuntimeIDs[name]; ok && oldRID != rid {
+		delete(m.itemRuntimeIDsToNames, oldRID)
+		delete(m.itemRuntimeIDToVersion, oldRID)
+		delete(m.itemRuntimeIDToData, oldRID)
+	}
+	if oldName, ok := m.itemRuntimeIDsToNames[rid]; ok && oldName != name {
+		delete(m.itemNamesToRuntimeIDs, oldName)
+	}
+
+	m.itemNamesToRuntimeIDs[name] = rid
+	m.itemRuntimeIDsToNames[rid] = name
+	m.itemRuntimeIDToVersion[rid] = version
+	if data != nil {
+		m.itemRuntimeIDToData[rid] = data
+	} else {
+		delete(m.itemRuntimeIDToData, rid)
+	}
+}
+
 func (m *DefaultItemMapping) Air() int32 {
 	defer m.mu.Unlock()
 	m.mu.Lock()